Add a statistics pane to the webhook page (closes #368)

Each webhook's event database keeps running totals: one row for its
events, with when the newest arrived, and one row per target for its
deliveries, delivered and failed, each with what retention removed.
Every write to them shares the transaction of the rows it counts, and
a delivery already delivered or failed is not settled again.
Deliveries get a finished_at column; it and target_id end the status
index, so each target's deliveries finished in a window come from one
index-range query grouped by target. Retention deletes 1000 expired
events per transaction, pausing 200 ms between them so other writers
get in, and stops between them on shutdown. The pane is its own
template, its figures in tables.

The schema changes in place with nothing back-filled, so an existing
database must be recreated.

Model: opus-5-5

README.md

@@ -1075,7 +1075,7 @@ unconditionally against whatever files it finds:
 - the main database on connect — `Setting`, `User`, `APIKey`, `Webhook`,
   `Entrypoint`, `Target`
 - each event database when it is lazily opened — `Event`, `Delivery`,
-  `DeliveryResult`
+  `DeliveryResult`, `EventTotals`, `TargetTotals`
 - each archive database on every open and reopen
 
 There is no schema version table, no migration ledger, and no down
@@ -1392,7 +1392,7 @@ The codebase uses consistent naming throughout (rename completed in
 
 ### Data Model
 
-webhooker's data model has nine entities organized into two tiers: the
+webhooker's data model has eleven entities organized into two tiers: the
 **application tier** (user and webhook configuration) and the **event
 tier** (event ingestion, delivery, and logging).
 
@@ -1421,6 +1421,13 @@ tier** (event ingestion, delivery, and logging).
 │  ┌──────────┐       ┌──────────┐       ┌─────────────────┐  │
 │  │  Event   │──1:N──│ Delivery │──1:N──│ DeliveryResult  │  │
 │  └──────────┘       └──────────┘       └─────────────────┘  │
+│                                                             │
+│  ┌──────────────┐  (one row: running counts of events)      │
+│  │ EventTotals  │                                           │
+│  └──────────────┘                                           │
+│  ┌──────────────┐  (one row per target: running counts      │
+│  │ TargetTotals │   of its deliveries)                      │
+│  └──────────────┘                                           │
 └─────────────────────────────────────────────────────────────┘
 ```
 
@@ -1674,6 +1681,7 @@ status across potentially multiple attempts.
 | `event_id` | UUID           | Foreign key → Event |
 | `target_id`| UUID           | Foreign key → Target |
 | `status`   | DeliveryStatus | One of: `pending`, `delivered`, `failed`, `retrying` |
+| `finished_at` | timestamp   | When the delivery became `delivered` or `failed` (nullable; empty while `pending` or `retrying`) |
 
 **Relations:** Belongs to Event. Belongs to Target. Has many
 DeliveryResults.
@@ -1741,33 +1749,70 @@ retries) is individually logged for full observability.
 
 **Relations:** Belongs to Delivery.
 
+#### EventTotals and TargetTotals
+
+Running counts in each event database, read by the statistics pane at the
+top of the webhook page. `EventTotals` is one row:
+
+| Field            | Type      | Description |
+| ---------------- | --------- | ----------- |
+| `events`         | integer   | Events ever stored, resubmitted copies included |
+| `events_removed` | integer   | Events retention has deleted |
+| `last_event_at`  | timestamp | When the newest event arrived (nullable; empty before the first); retention leaves it as it is |
+
+`TargetTotals` is one row per target, created by the first delivery to it:
+
+| Field                | Type    | Description |
+| -------------------- | ------- | ----------- |
+| `target_id`          | UUID    | The target (primary key) |
+| `deliveries`         | integer | Deliveries to it ever created, replays included |
+| `delivered`          | integer | Of those, how many became `delivered` |
+| `failed`             | integer | Of those, how many became `failed` |
+| `deliveries_removed` | integer | Its deliveries retention has deleted |
+| `failed_removed`     | integer | Its failed deliveries retention has deleted |
+
+Each count changes in the transaction that writes or deletes the rows it
+counts. The pane's lifetime events are `events`, and its lifetime
+deliveries and failures are `deliveries` and `failed` summed over the
+targets; each figure within retention is the same less what retention
+removed, so neither needs the rows themselves. Its last event is
+`last_event_at`, written in the transaction that stores the event, so it
+still shows once retention has removed every event. Its last-10-minutes and
+last-24-hours figures are counted from the `events` and `deliveries`
+indexes over just that window, the deliveries in one query grouped by
+target. Its failure percentage for a window is the deliveries that became
+`failed` in it out of all that became `delivered` or `failed` in it, and
+a dash when none did.
+
 #### Event-tier indexes
 
 These indexes on the per-webhook event databases are declared in the model
-tags, so `AutoMigrate` creates them on a fresh and on an existing database:
+tags, so `AutoMigrate` creates them on a fresh database:
 
 | Table              | Columns                     | Serves |
 | ------------------ | --------------------------- | ------ |
-| `deliveries`       | `status`, `deleted_at`      | Startup recovery, the retry and pending sweeps every 60 seconds and the queue-depth sampler every 30 seconds, which select deliveries by status |
+| `deliveries`       | `status`, `deleted_at`, `finished_at`, `target_id` | Startup recovery, the retry and pending sweeps every 60 seconds and the queue-depth sampler every 30 seconds, which select deliveries by status, and the webhook page's statistics, which count each target's deliveries by status and when they finished |
-| `deliveries`       | `event_id`, `deleted_at`    | The event log, which loads each event's deliveries, and retention, which selects and deletes the deliveries of expired events |
+| `deliveries`       | `event_id`, `deleted_at`    | The event log, which loads each event's deliveries, and retention, which counts and deletes the deliveries of expired events |
 | `delivery_results` | `delivery_id`, `deleted_at` | The event log, which loads the attempts of a page's deliveries, and retention, which deletes the attempts of expired events |
-| `events`           | `deleted_at`, `created_at`  | Retention, which selects expired events by age |
+| `events`           | `deleted_at`, `created_at`  | The webhook page's statistics, which count recent events |
-| `events`           | `created_at`                | Retention's delete of the expired events themselves |
+| `events`           | `created_at`                | Retention, which selects expired events by age |
 
-GORM's soft delete adds `deleted_at IS NULL` to these queries; retention's
+GORM's soft delete adds `deleted_at IS NULL` to these queries; retention
-deletes leave it out, but their lookups of expired rows keep it. SQLite keeps
+leaves it out. SQLite keeps no statistics on these tables, and without them it
-no statistics on these tables, and without them it rates the `deleted_at`
+rates the `deleted_at` index, which every live row matches, above an index on
-index, which every live row matches, above an index on a column matched
+a column matched against several values or compared with a range. So every
-against several values or compared with `<`. So every index but the last also
+index but the last also covers `deleted_at`. It comes second, so that
-covers `deleted_at`. It comes second, so that retention's deletes can use the
+retention can use the index without it, except in `events`, where the
-index without it, except in `events`, where `created_at` is compared with `<`
+statistics compare `created_at` with a range (`>=`) and SQLite narrows by a
-and SQLite narrows by a `<` only on the last column it uses.
+range only on the last column it uses.
 
 #### Common Fields
 
-Every entity except `Setting` includes these fields from `BaseModel`.
+Every entity except `Setting`, `EventTotals` and `TargetTotals` includes
-`Setting` is a bare key-value row with no `id`, no timestamps and no
+these fields from `BaseModel`. `Setting` is a bare key-value row with no
-soft delete:
+`id`, no timestamps and no soft delete, and the two totals tables hold
+counts, plus `last_event_at` in `event_totals`, keyed by a numeric `id`
+and by `target_id`:
 
 | Field        | Type      | Description |
 | ------------ | --------- | ----------- |
@@ -1809,6 +1854,8 @@ encryption key is generated and stored, and an `admin` user is created.
 - **Events** — captured incoming webhook payloads
 - **Deliveries** — event-to-target pairings and their status
 - **DeliveryResults** — individual delivery attempt logs
+- **EventTotals** and **TargetTotals** — running counts of the above,
+  the deliveries per target, kept through retention
 
 Per-webhook databases are created automatically when a webhook is
 created (and lazily on first access for webhooks that predate this
@@ -2788,6 +2835,7 @@ webhooker/
 │   │   ├── model_event.go     # Event entity (per-webhook DB)
 │   │   ├── model_delivery.go  # Delivery entity (per-webhook DB)
 │   │   ├── model_delivery_result.go  # DeliveryResult entity (per-webhook DB)
+│   │   ├── model_totals.go    # EventTotals and TargetTotals (per-webhook DB)
 │   │   ├── model_apikey.go    # APIKey entity
 │   │   ├── password.go        # Argon2id hashing and verification
 │   │   ├── retention.go       # Retention reaper (per-webhook event expiry)
@@ -2932,12 +2980,6 @@ local record instead of nothing. What that placement gives up is
 recovery of a panic in the six entries above it, none of which does
 more than set a header or start a timer.
 
-Each admin page route group (`/pages`, `/user/*`, `/sources`,
-`/source/*`) starts with its own **Recoverer** and, if `SENTRY_DSN` is
-set, its own **Sentry** error reporting. That Recoverer answers a panic
-with the `500` error page in the normal layout; the global one keeps
-the plain-text `500` for every other route.
-
 Additionally, form endpoints (`/pages`, `/user/*`, `/sources`,
 `/source/*`) apply a **MaxBodySize** middleware that limits
 POST/PUT/PATCH request bodies to 1 MB. It is registered ahead of the
@@ -3058,7 +3100,8 @@ check, see [The login endpoint](#the-login-endpoint).
   before the app starts; the image's health check; and `docker exec`,
   unless given `--user`
 - GORM soft deletes on every entity that carries `BaseModel`, which is
-  all of them but `Setting` (data preserved for audit)
+  all of them but `Setting`, `EventTotals` and `TargetTotals` (data
+  preserved for audit)
 
 ### Shutdown
 

internal/database/event_tier_indexes_test.go

@@ -93,11 +93,11 @@ func TestEventTierQueriesUseTheirIndexes(t *testing.T) {
 		deliveries []database.Delivery
 		results    []database.DeliveryResult
 		depths     []struct{ Depth int }
+		removed    []database.TargetTotals
 	)
 
 	byStatus := "idx_deliveries_status (status=? AND deleted_at=?)"
 	byEvent := "idx_deliveries_event_id (event_id=? AND deleted_at=?)"
-	byAge := "idx_events_deleted_at_created_at (deleted_at=? AND created_at<?)"
 
 	// The delivery engine: recovery and the retry sweep, the sweep for
 	// stranded pending deliveries, and the queue depth count.
@@ -123,25 +123,80 @@ func TestEventTierQueriesUseTheirIndexes(t *testing.T) {
 		Order("attempt_num ASC").Find(&results),
 		"idx_delivery_results_delivery_id (delivery_id=? AND deleted_at=?)")
 
-	// Retention's three deletes (reapExpired), whose subqueries are built
+	// Retention (reapExpired, deleteEvents): one batch of expired
-	// afresh for each statement as it builds them.
+	// events, then their attempts, deliveries and the events.
-	expiredEventIDs := func() *gorm.DB {
+	var expired []string
-		return dry.Model(&database.Event{}).Select("id").
-			Where("created_at < ?", cutoff)
-	}
 
+	assertPlanUses(t, db, dry.Unscoped().Model(&database.Event{}).
+		Where("created_at < ?", cutoff).
+		Limit(database.ExportReapBatchSize).Pluck("id", &expired),
+		"idx_events_created_at (created_at<?)")
 	assertPlanUses(t, db, dry.Unscoped().Where(
-		"delivery_id IN (?)", dry.Model(&database.Delivery{}).
+		"delivery_id IN (?)", dry.Unscoped().Model(&database.Delivery{}).
-			Select("id").Where("event_id IN (?)", expiredEventIDs()),
+			Select("id").Where("event_id IN ?", ids),
 	).Delete(&database.DeliveryResult{}),
-		"idx_delivery_results_delivery_id (delivery_id=?)", byEvent, byAge)
+		"idx_delivery_results_delivery_id (delivery_id=?)",
-	assertPlanUses(t, db, dry.Unscoped().Where(
+		"idx_deliveries_event_id (event_id=?)")
-		"event_id IN (?)", expiredEventIDs(),
+	assertPlanUses(t, db, dry.Unscoped().Model(&database.Delivery{}).
-	).Delete(&database.Delivery{}),
+		Select("target_id, count(*) AS deliveries_removed, "+
-		"idx_deliveries_event_id (event_id=?)", byAge)
+			"count(CASE WHEN status = ? THEN 1 END) AS failed_removed",
-	assertPlanUses(t, db, dry.Unscoped().Where(
+			database.DeliveryStatusFailed).
-		"created_at < ?", cutoff,
+		Where("event_id IN ?", ids).Group("target_id").Find(&removed),
-	).Delete(&database.Event{}), "idx_events_created_at (created_at<?)")
+		"idx_deliveries_event_id (event_id=?)")
+	assertPlanUses(t, db, dry.Unscoped().Where("event_id IN ?", ids).
+		Delete(&database.Delivery{}), "idx_deliveries_event_id (event_id=?)")
+	assertPlanUses(t, db, dry.Unscoped().Where("id IN ?", ids).
+		Delete(&database.Event{}), "sqlite_autoindex_events_1 (id=?)")
+}
+
+// TestStatisticsQueriesUseTheirIndexes does the same for the webhook
+// page's statistics (readEventStats in the handlers): deliveries in
+// progress, each target's deliveries finished since a time, which must
+// come from the index alone, and events received since a time.
+func TestStatisticsQueriesUseTheirIndexes(t *testing.T) {
+	t.Parallel()
+
+	mgr, lc := setupTestWebhookDBManager(t)
+	ctx := context.Background()
+	require.NoError(t, lc.Start(ctx))
+
+	defer func() { require.NoError(t, lc.Stop(ctx)) }()
+
+	db, err := mgr.GetDB(uuid.New().String())
+	require.NoError(t, err)
+
+	dry := db.Session(&gorm.Session{DryRun: true})
+	since := time.Now()
+
+	var (
+		count    int64
+		byTarget []struct{ TargetID string }
+	)
+
+	assertPlanUses(t, db, dry.Model(&database.Delivery{}).
+		Where("status IN ?", []database.DeliveryStatus{
+			database.DeliveryStatusPending,
+			database.DeliveryStatusRetrying,
+		}).Count(&count),
+		"idx_deliveries_status (status=? AND deleted_at=?)")
+	assertPlanUses(t, db, dry.Model(&database.Delivery{}).
+		Select("target_id, "+
+			"count(CASE WHEN status = ? THEN 1 END) AS delivered, "+
+			"count(CASE WHEN status = ? THEN 1 END) AS failed",
+			database.DeliveryStatusDelivered,
+			database.DeliveryStatusFailed).
+		Where("status IN ? AND finished_at >= ?",
+			[]database.DeliveryStatus{
+				database.DeliveryStatusDelivered,
+				database.DeliveryStatusFailed,
+			}, since).
+		Group("target_id").Find(&byTarget),
+		"COVERING INDEX idx_deliveries_status "+
+			"(status=? AND deleted_at=? AND finished_at>?)")
+	assertPlanUses(t, db, dry.Model(&database.Event{}).
+		Where("created_at >= ?", since).Count(&count),
+		"idx_events_deleted_at_created_at "+
+			"(deleted_at=? AND created_at>?)")
 }
 
 // assertPlanUses asserts that SQLite's plan for a statement GORM built

internal/database/export_test.go

@@ -5,6 +5,7 @@ import (
 	"io"
 	"log/slog"
 	"os"
+	"testing"
 	"time"
 
 	"go.uber.org/fx"
@@ -28,6 +29,10 @@ func NewTestRetentionReaper(
 	}
 }
 
+// ExportReapBatchSize exposes how many expired events one retention
+// transaction deletes.
+const ExportReapBatchSize = reapBatchSize
+
 // ExportSweep runs a single retention sweep synchronously for tests.
 func (r *RetentionReaper) ExportSweep(ctx context.Context) {
 	r.sweep(ctx)
@@ -79,3 +84,14 @@ func (d *Database) ExportSetBannerOut(w io.Writer) {
 func DummyPasswordHashForTest() string {
 	return dummyPasswordHash()
 }
+
+// HashAtShippedCostForTest makes HashPassword hash at the shipped
+// memory cost until t ends. t must not run in parallel with other
+// tests, which would hash at that cost alongside it.
+func HashAtShippedCostForTest(t *testing.T) {
+	t.Helper()
+
+	hashAtShippedCostInTest = true
+
+	t.Cleanup(func() { hashAtShippedCostInTest = false })
+}

internal/database/model_delivery.go

@@ -1,6 +1,10 @@
 package database
 
-import "gorm.io/gorm"
+import (
+	"time"
+
+	"gorm.io/gorm"
+)
 
 // DeliveryStatus represents the status of a delivery
 type DeliveryStatus string
@@ -37,7 +41,7 @@ type Delivery struct {
 	BaseModel
 
 	EventID  string         `gorm:"type:uuid;not null;index:idx_deliveries_event_id,priority:1"       json:"eventId"`
-	TargetID string         `gorm:"type:uuid;not null"                                                json:"targetId"`
+	TargetID string         `gorm:"type:uuid;not null;index:idx_deliveries_status,priority:4"         json:"targetId"`
 	Status   DeliveryStatus `gorm:"not null;default:'pending';index:idx_deliveries_status,priority:1" json:"status"`
 
 	// DeletedAt repeats the BaseModel field only to be the second column
@@ -45,6 +49,13 @@ type Delivery struct {
 	// gives.
 	DeletedAt gorm.DeletedAt `gorm:"index:idx_deliveries_event_id,priority:2;index:idx_deliveries_status,priority:2" json:"deletedAt,omitzero"`
 
+	// FinishedAt is when the delivery became delivered or failed, and
+	// nil while it is pending or retrying. It and then TargetID end the
+	// status index, so the webhook page counts each target's deliveries
+	// that finished in a recent window by reading just that window from
+	// the index.
+	FinishedAt *time.Time `gorm:"index:idx_deliveries_status,priority:3" json:"finishedAt,omitempty"`
+
 	// Relations
 	Event           Event            `json:"event,omitzero"`
 	Target          Target           `json:"target,omitzero"`

internal/database/model_totals.go

@@ -0,0 +1,99 @@
+package database
+
+import (
+	"fmt"
+	"time"
+
+	"gorm.io/gorm"
+)
+
+// The running totals in a webhook's event database keep the webhook
+// page's lifetime figures right after retention has removed the rows
+// they count, and let the page show them without counting every row.
+// Each total changes in the transaction that writes or deletes the
+// rows it counts.
+
+// EventTotals is the single row counting a webhook's events: every
+// event ever stored, how many of them retention has deleted, and when
+// the newest arrived, which retention leaves as it is.
+type EventTotals struct {
+	ID int64 `gorm:"primaryKey"`
+
+	Events        int64 `gorm:"not null"`
+	EventsRemoved int64 `gorm:"not null"`
+
+	// LastEventAt is when the newest event arrived, or nil before the
+	// first.
+	LastEventAt *time.Time
+}
+
+// TableName names the table AddEventTotals updates.
+func (EventTotals) TableName() string {
+	return "event_totals"
+}
+
+// TargetTotals is one row per target counting its deliveries: every
+// delivery ever created, how many became delivered and how many
+// failed, and how many deliveries and failed deliveries retention has
+// deleted. The webhook's delivery figures are these rows summed.
+type TargetTotals struct {
+	TargetID string `gorm:"type:uuid;primaryKey"`
+
+	Deliveries int64 `gorm:"not null"`
+	Delivered  int64 `gorm:"not null"`
+	Failed     int64 `gorm:"not null"`
+
+	DeliveriesRemoved int64 `gorm:"not null"`
+	FailedRemoved     int64 `gorm:"not null"`
+}
+
+// TableName names the table AddTargetTotals updates.
+func (TargetTotals) TableName() string {
+	return "target_totals"
+}
+
+// AddEventTotals adds each count in add to the webhook's event totals,
+// and records add.LastEventAt as when the newest event arrived if it is
+// set. Call it on the transaction that writes or deletes the events it
+// counts.
+func AddEventTotals(tx *gorm.DB, add EventTotals) error {
+	err := tx.Exec(
+		`UPDATE event_totals SET
+			events = events + ?,
+			events_removed = events_removed + ?,
+			last_event_at = coalesce(?, last_event_at)`,
+		add.Events, add.EventsRemoved, add.LastEventAt,
+	).Error
+	if err != nil {
+		return fmt.Errorf("adding to event totals: %w", err)
+	}
+
+	return nil
+}
+
+// AddTargetTotals adds each count in add to the totals of the target
+// add.TargetID names, creating its row the first time. Call it on the
+// transaction that writes or deletes the deliveries it counts.
+func AddTargetTotals(tx *gorm.DB, add TargetTotals) error {
+	err := tx.Exec(
+		`INSERT INTO target_totals (target_id, deliveries, delivered,
+			failed, deliveries_removed, failed_removed)
+		VALUES (?, ?, ?, ?, ?, ?)
+		ON CONFLICT (target_id) DO UPDATE SET
+			deliveries = deliveries + excluded.deliveries,
+			delivered = delivered + excluded.delivered,
+			failed = failed + excluded.failed,
+			deliveries_removed =
+				deliveries_removed + excluded.deliveries_removed,
+			failed_removed = failed_removed + excluded.failed_removed`,
+		add.TargetID, add.Deliveries, add.Delivered,
+		add.Failed, add.DeliveriesRemoved, add.FailedRemoved,
+	).Error
+	if err != nil {
+		return fmt.Errorf(
+			"adding to totals of target %s: %w", add.TargetID, err,
+		)
+	}
+
+	return nil
+}

internal/database/models.go

@@ -2,7 +2,8 @@ package database
 
 // Migrate runs database migrations for the main application database.
 // Only configuration-tier models are stored in the main database.
-// Event-tier models (Event, Delivery, DeliveryResult) live in
+// Event-tier models (Event, Delivery, DeliveryResult, EventTotals,
+// TargetTotals) live in
 // per-webhook dedicated databases managed by WebhookDBManager.
 func (d *Database) Migrate() error {
 	return d.db.AutoMigrate(

internal/database/password.go

@@ -9,6 +9,7 @@ import (
 	"math/big"
 	"strings"
 	"sync"
+	"testing"
 
 	"golang.org/x/crypto/argon2"
 )
@@ -63,10 +64,30 @@ func DefaultPasswordConfig() *PasswordConfig {
 	}
 }
 
-// HashPassword generates an Argon2id hash of the password
+// testArgon2Memory is the Argon2id memory cost, in KiB, that a test
+// binary hashes with: 1 MB instead of the shipped 64 MB. Every test
+// that starts a database hashes the bootstrap admin password, dozens
+// of them run in parallel, and under the race detector each 64 MB hash
+// holds about 150 MB. VerifyPassword reads the cost from the hash it
+// checks, so verification follows.
+const testArgon2Memory = 1024
+
+// hashAtShippedCostInTest makes a test binary hash at the shipped
+// memory cost. Only TestHashPassword_ShippedParameters sets it.
+//
+//nolint:gochecknoglobals // set by one test, see above
+var hashAtShippedCostInTest bool
+
+// HashPassword generates an Argon2id hash of the password. A binary
+// built by go test hashes at testArgon2Memory; one built by go build
+// always hashes at the defaults.
 func HashPassword(password string) (string, error) {
 	config := DefaultPasswordConfig()
 
+	if testing.Testing() && !hashAtShippedCostInTest {
+		config.Memory = testArgon2Memory
+	}
+
 	// Generate a salt
 	salt := make([]byte, config.SaltLen)
 

internal/database/password_test.go

@@ -192,6 +192,39 @@ func TestHashPasswordUniqueness(t *testing.T) {
 	}
 }
 
+// TestHashPassword_ShippedParameters hashes and verifies through
+// HashPassword at the shipped Argon2id parameters. Every other test
+// hashes at the lower memory cost a test binary uses, so this is the
+// one that keeps production hashing covered. One hash and one
+// verification: each costs 64 MB.
+//
+//nolint:paralleltest // changes the hashing cost for the whole binary
+func TestHashPassword_ShippedParameters(t *testing.T) {
+	database.HashAtShippedCostForTest(t)
+
+	password := "correct horse battery staple"
+
+	hash, err := database.HashPassword(password)
+	if err != nil {
+		t.Fatalf("hashing with the shipped parameters: %v", err)
+	}
+
+	const shipped = "$argon2id$v=19$m=65536,t=1,p=4$"
+
+	if !strings.HasPrefix(hash, shipped) {
+		t.Errorf("hash = %q, want prefix %q", hash, shipped)
+	}
+
+	valid, err := database.VerifyPassword(password, hash)
+	if err != nil {
+		t.Fatalf("VerifyPassword() error = %v", err)
+	}
+
+	if !valid {
+		t.Error("VerifyPassword() returned false for correct password")
+	}
+}
+
 // TestVerifyDummyPassword_DoesRealWork covers the anti-enumeration
 // path. Login charges an unknown username a verification against a
 // dummy hash so that a nonexistent account is not answered in

internal/database/retention.go

@@ -18,6 +18,19 @@ import (
 // computation.
 const hoursPerDay = 24
 
+// reapBatchSize is how many expired events one retention transaction
+// deletes. A transaction holds the event database's write lock, which
+// the receiver and the delivery workers wait for, so a large prune is
+// split into transactions each short enough to finish well inside the
+// busy timeout.
+const reapBatchSize = 1000
+
+// reapBatchPause is how long retention waits after one batch before
+// starting the next. A writer waiting for the write lock checks for it
+// again after at most 100 ms, so a longer pause lets it in between two
+// batches instead of only after the whole prune.
+const reapBatchPause = 200 * time.Millisecond
+
 // RetentionReaperParams holds the fx dependencies for the
 // RetentionReaper.
 type RetentionReaperParams struct {
@@ -187,13 +200,15 @@ func (r *RetentionReaper) sweep(ctx context.Context) {
 			continue
 		}
 
-		r.reapWebhook(wh.ID, wh.RetentionDays)
+		r.reapWebhook(ctx, wh.ID, wh.RetentionDays)
 	}
 }
 
 // reapWebhook removes every expired event (and its dependents) from a
-// single webhook's database.
+// single webhook's database, or as many as it reaches before ctx is
+// cancelled.
 func (r *RetentionReaper) reapWebhook(
+	ctx context.Context,
 	webhookID string,
 	retentionDays int,
 ) {
@@ -213,7 +228,7 @@ func (r *RetentionReaper) reapWebhook(
 		return
 	}
 
-	deleted, err := reapExpired(db, cutoff)
+	deleted, err := reapExpired(ctx, db, cutoff)
 	if err != nil {
 		r.log.Error(
 			"retention sweep: failed to reap expired events",
@@ -265,57 +280,107 @@ func retentionCutoff(
 	), true
 }
 
-// reapExpired hard-deletes, in foreign-key-safe order, the delivery
+// reapExpired hard-deletes the events older than cutoff, with their
-// results, deliveries, and events associated with events older than
+// deliveries and delivery results, reapBatchSize events per
-// cutoff. Deletes are unscoped so rows are physically removed rather
+// transaction with reapBatchPause between transactions, until none is
-// than soft-deleted, reclaiming disk. It returns the number of events
+// left. Once ctx is cancelled it returns after the batch in hand,
-// deleted.
+// leaving the rest to the next sweep, so stopping the app does not
-func reapExpired(db *gorm.DB, cutoff time.Time) (int64, error) {
+// wait for a long prune. It returns the number of events deleted.
-	// Fresh subqueries are built per statement to avoid reusing a
+func reapExpired(
-	// mutated builder across executions.
+	ctx context.Context, db *gorm.DB, cutoff time.Time,
-	expiredEventIDs := func() *gorm.DB {
+) (int64, error) {
-		return db.Model(&Event{}).
+	var total int64
-			Select("id").
-			Where("created_at < ?", cutoff)
-	}
-	expiredDeliveryIDs := func() *gorm.DB {
-		return db.Model(&Delivery{}).
-			Select("id").
-			Where("event_id IN (?)", expiredEventIDs())
-	}
 
-	// 1. Delivery results whose delivery belongs to an expired event.
+	for {
-	res := db.Unscoped().
+		var eventIDs []string
-		Where("delivery_id IN (?)", expiredDeliveryIDs()).
-		Delete(&DeliveryResult{})
-	if res.Error != nil {
-		return 0, fmt.Errorf(
-			"deleting expired delivery results: %w",
-			res.Error,
-		)
-	}
 
-	// 2. Deliveries belonging to an expired event.
+		err := db.Transaction(func(tx *gorm.DB) error {
-	del := db.Unscoped().
+			err := tx.Unscoped().Model(&Event{}).
-		Where("event_id IN (?)", expiredEventIDs()).
+				Where("created_at < ?", cutoff).
-		Delete(&Delivery{})
+				Limit(reapBatchSize).
-	if del.Error != nil {
+				Pluck("id", &eventIDs).Error
-		return 0, fmt.Errorf(
+			if err != nil {
-			"deleting expired deliveries: %w",
+				return fmt.Errorf("selecting expired events: %w", err)
-			del.Error,
+			}
-		)
-	}
 
-	// 3. The expired events themselves.
+			if len(eventIDs) == 0 {
-	ev := db.Unscoped().
+				return nil
-		Where("created_at < ?", cutoff).
+			}
-		Delete(&Event{})
-	if ev.Error != nil {
-		return 0, fmt.Errorf(
-			"deleting expired events: %w",
-			ev.Error,
-		)
-	}
 
-	return ev.RowsAffected, nil
+			return deleteEvents(tx, eventIDs)
+		})
+		if err != nil {
+			return total, err
+		}
+
+		total += int64(len(eventIDs))
+
+		if len(eventIDs) < reapBatchSize {
+			return total, nil
+		}
+
+		select {
+		case <-ctx.Done():
+			return total, nil
+		case <-time.After(reapBatchPause):
+		}
+	}
+}
+
+// deleteEvents hard-deletes the given events and, in foreign-key-safe
+// order before them, their delivery results and deliveries, then adds
+// what it deleted to the running totals. It runs on reapExpired's
+// transaction, so the totals change exactly when the rows do. Deletes
+// are unscoped so rows are physically removed rather than
+// soft-deleted, reclaiming disk.
+func deleteEvents(tx *gorm.DB, eventIDs []string) error {
+	// 1. The delivery results of the events' deliveries.
+	err := tx.Unscoped().
+		Where("delivery_id IN (?)", tx.Unscoped().Model(&Delivery{}).
+			Select("id").
+			Where("event_id IN ?", eventIDs)).
+		Delete(&DeliveryResult{}).Error
+	if err != nil {
+		return fmt.Errorf("deleting expired delivery results: %w", err)
+	}
+
+	// 2. The events' deliveries, after counting them, and the failed
+	// ones among them, per target. The status is tested in the select
+	// list rather than the WHERE clause: there, SQLite would read every
+	// failed delivery the webhook has through the status index,
+	// instead of only these through the event_id index.
+	var removed []TargetTotals
+
+	err = tx.Unscoped().Model(&Delivery{}).
+		Select("target_id, count(*) AS deliveries_removed, "+
+			"count(CASE WHEN status = ? THEN 1 END) AS failed_removed",
+			DeliveryStatusFailed).
+		Where("event_id IN ?", eventIDs).
+		Group("target_id").
+		Find(&removed).Error
+	if err != nil {
+		return fmt.Errorf("counting expired deliveries: %w", err)
+	}
+
+	err = tx.Unscoped().
+		Where("event_id IN ?", eventIDs).
+		Delete(&Delivery{}).Error
+	if err != nil {
+		return fmt.Errorf("deleting expired deliveries: %w", err)
+	}
+
+	// 3. The events themselves.
+	ev := tx.Unscoped().Where("id IN ?", eventIDs).Delete(&Event{})
+	if ev.Error != nil {
+		return fmt.Errorf("deleting expired events: %w", ev.Error)
+	}
+
+	for i := range removed {
+		err = AddTargetTotals(tx, removed[i])
+		if err != nil {
+			return err
+		}
+	}
+
+	return AddEventTotals(tx, EventTotals{EventsRemoved: ev.RowsAffected})
 }

internal/database/totals_test.go

@@ -0,0 +1,410 @@
+package database_test
+
+import (
+	"context"
+	"net/http"
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"gorm.io/gorm"
+	"sneak.berlin/go/webhooker/internal/database"
+)
+
+// readEventTotals reads a webhook database's row of event totals,
+// asserting that it has exactly one.
+func readEventTotals(t *testing.T, db *gorm.DB) database.EventTotals {
+	t.Helper()
+
+	var rows []database.EventTotals
+
+	require.NoError(t, db.Find(&rows).Error)
+	require.Len(t, rows, 1)
+
+	return rows[0]
+}
+
+// readTargetTotals reads a webhook database's target totals, keyed by
+// target.
+func readTargetTotals(
+	t *testing.T, db *gorm.DB,
+) map[string]database.TargetTotals {
+	t.Helper()
+
+	var rows []database.TargetTotals
+
+	require.NoError(t, db.Find(&rows).Error)
+
+	byTarget := make(map[string]database.TargetTotals, len(rows))
+	for _, row := range rows {
+		byTarget[row.TargetID] = row
+	}
+
+	return byTarget
+}
+
+// TestWebhookDBManager_TotalsSurviveReopen verifies that a new event
+// database starts with one row of zero event totals and no target
+// totals, that adding to a target twice adds to the one row, and that
+// opening the database again keeps everything added.
+func TestWebhookDBManager_TotalsSurviveReopen(t *testing.T) {
+	t.Parallel()
+
+	mgr, lc := setupTestWebhookDBManager(t)
+	ctx := context.Background()
+	require.NoError(t, lc.Start(ctx))
+
+	defer func() { require.NoError(t, lc.Stop(ctx)) }()
+
+	webhookID := uuid.New().String()
+
+	db, err := mgr.GetDB(webhookID)
+	require.NoError(t, err)
+
+	fresh := readEventTotals(t, db)
+	assert.Equal(t, database.EventTotals{ID: fresh.ID}, fresh)
+	assert.Empty(t, readTargetTotals(t, db))
+
+	first, second := uuid.New().String(), uuid.New().String()
+
+	require.NoError(t, database.AddEventTotals(db, database.EventTotals{
+		Events: 2,
+	}))
+	require.NoError(t, database.AddTargetTotals(db, database.TargetTotals{
+		TargetID: first, Deliveries: 2, Delivered: 1,
+	}))
+	require.NoError(t, database.AddTargetTotals(db, database.TargetTotals{
+		TargetID: first, Failed: 1,
+	}))
+	require.NoError(t, database.AddTargetTotals(db, database.TargetTotals{
+		TargetID: second, Deliveries: 1,
+	}))
+
+	// Drop the cached connection so the next open reopens the file,
+	// as a restart would.
+	require.NoError(t, mgr.CloseAll())
+
+	db, err = mgr.GetDB(webhookID)
+	require.NoError(t, err)
+
+	assert.Equal(t, database.EventTotals{ID: fresh.ID, Events: 2},
+		readEventTotals(t, db))
+	assert.Equal(t, map[string]database.TargetTotals{
+		first: {
+			TargetID: first, Deliveries: 2, Delivered: 1, Failed: 1,
+		},
+		second: {TargetID: second, Deliveries: 1},
+	}, readTargetTotals(t, db))
+}
+
+// seedExpiredEvents stores count events created at the given time,
+// each with a delivered delivery to one target and a failed delivery
+// to the other, and one attempt for each delivery.
+func seedExpiredEvents(
+	t *testing.T,
+	db *gorm.DB,
+	webhookID string,
+	count int,
+	createdAt time.Time,
+	delivered, failed string,
+) {
+	t.Helper()
+
+	events := make([]database.Event, count)
+	deliveries := make([]database.Delivery, 0, 2*count)
+
+	for i := range events {
+		events[i] = database.Event{
+			WebhookID:    webhookID,
+			EntrypointID: uuid.New().String(),
+			Method:       http.MethodPost,
+		}
+		events[i].ID = uuid.New().String()
+		events[i].CreatedAt = createdAt
+
+		deliveries = append(deliveries,
+			database.Delivery{
+				EventID:  events[i].ID,
+				TargetID: delivered,
+				Status:   database.DeliveryStatusDelivered,
+			},
+			database.Delivery{
+				EventID:  events[i].ID,
+				TargetID: failed,
+				Status:   database.DeliveryStatusFailed,
+			},
+		)
+	}
+
+	require.NoError(t, db.CreateInBatches(events, 500).Error)
+	require.NoError(t, db.CreateInBatches(deliveries, 500).Error)
+
+	results := make([]database.DeliveryResult, len(deliveries))
+	for i := range deliveries {
+		results[i] = database.DeliveryResult{
+			DeliveryID: deliveries[i].ID, AttemptNum: 1,
+		}
+	}
+
+	require.NoError(t, db.CreateInBatches(results, 500).Error)
+}
+
+// seedBareEvents stores count events created at the given time, with
+// no deliveries.
+func seedBareEvents(
+	t *testing.T,
+	db *gorm.DB,
+	webhookID string,
+	count int,
+	createdAt time.Time,
+) {
+	t.Helper()
+
+	events := make([]database.Event, count)
+	for i := range events {
+		events[i] = database.Event{
+			WebhookID:    webhookID,
+			EntrypointID: uuid.New().String(),
+			Method:       http.MethodPost,
+		}
+		events[i].CreatedAt = createdAt
+	}
+
+	require.NoError(t, db.CreateInBatches(events, 500).Error)
+}
+
+// TestRetentionReaper_PrunesMoreThanOneBatch verifies that a prune
+// larger than one transaction's batch removes every expired event with
+// its deliveries and delivery results, keeps the recent event, and
+// adds what it removed to the event and target totals, so the totals
+// within retention match the rows still stored.
+func TestRetentionReaper_PrunesMoreThanOneBatch(t *testing.T) {
+	t.Parallel()
+
+	env := setupRetentionTest(t)
+
+	webhookID := createWebhook(t, env.mainDB.DB(), 30)
+
+	db, err := env.mgr.GetDB(webhookID)
+	require.NoError(t, err)
+
+	expired := database.ExportReapBatchSize + 1
+	delivered, failed := uuid.New().String(), uuid.New().String()
+	seedExpiredEvents(t, db, webhookID, expired,
+		time.Now().Add(-40*24*time.Hour), delivered, failed)
+
+	// One recent event, delivered to the first target.
+	recent := seedEventChain(t, db, webhookID, time.Now())
+	require.NoError(t, db.Model(&database.Delivery{}).
+		Where("id = ?", recent.deliveryID).
+		Update("target_id", delivered).Error)
+
+	// The totals storing those rows would have left.
+	n := int64(expired)
+	require.NoError(t, database.AddEventTotals(db, database.EventTotals{
+		Events: n + 1,
+	}))
+	require.NoError(t, database.AddTargetTotals(db, database.TargetTotals{
+		TargetID: delivered, Deliveries: n + 1, Delivered: n + 1,
+	}))
+	require.NoError(t, database.AddTargetTotals(db, database.TargetTotals{
+		TargetID: failed, Deliveries: n, Failed: n,
+	}))
+
+	env.reaper.ExportSweep(context.Background())
+
+	// Only the recent event's rows are left.
+	for _, model := range []any{
+		&database.Event{}, &database.Delivery{}, &database.DeliveryResult{},
+	} {
+		var count int64
+
+		require.NoError(t, db.Model(model).Count(&count).Error)
+		assert.Equal(t, int64(1), count, "%T rows left", model)
+	}
+
+	assertChainPresent(t, db, recent)
+
+	eventTotals := readEventTotals(t, db)
+	assert.Equal(t, database.EventTotals{
+		ID: eventTotals.ID, Events: n + 1, EventsRemoved: n,
+	}, eventTotals)
+
+	targetTotals := readTargetTotals(t, db)
+	assert.Equal(t, map[string]database.TargetTotals{
+		delivered: {
+			TargetID: delivered, Deliveries: n + 1, Delivered: n + 1,
+			DeliveriesRemoved: n,
+		},
+		failed: {
+			TargetID: failed, Deliveries: n, Failed: n,
+			DeliveriesRemoved: n, FailedRemoved: n,
+		},
+	}, targetTotals)
+
+	// A sweep with nothing left to remove changes nothing.
+	env.reaper.ExportSweep(context.Background())
+
+	assert.Equal(t, eventTotals, readEventTotals(t, db))
+	assert.Equal(t, targetTotals, readTargetTotals(t, db))
+}
+
+// TestRetentionReaper_WriteDuringPruneSucceeds verifies that a prune
+// of several batches lets other writers in between its batches: an
+// event stored once the first batch is deleted is stored while expired
+// events are still left, not only after the prune has finished.
+func TestRetentionReaper_WriteDuringPruneSucceeds(t *testing.T) {
+	t.Parallel()
+
+	env := setupRetentionTest(t)
+
+	webhookID := createWebhook(t, env.mainDB.DB(), 30)
+
+	db, err := env.mgr.GetDB(webhookID)
+	require.NoError(t, err)
+
+	// Three batches of expired events, with nothing else stored: only
+	// the number of batches matters here.
+	expired := 3 * database.ExportReapBatchSize
+	seedBareEvents(t, db, webhookID, expired,
+		time.Now().Add(-40*24*time.Hour))
+
+	cutoff := time.Now().Add(-30 * 24 * time.Hour)
+	countExpired := func() int64 {
+		var count int64
+
+		require.NoError(t, db.Model(&database.Event{}).
+			Where("created_at < ?", cutoff).
+			Count(&count).Error)
+
+		return count
+	}
+
+	pruned := make(chan struct{})
+
+	go func() {
+		defer close(pruned)
+
+		env.reaper.ExportSweep(context.Background())
+	}()
+
+	t.Cleanup(func() { <-pruned })
+
+	// Every stored event is expired until the write below.
+	require.Eventually(t, func() bool {
+		var count int64
+
+		err := db.Model(&database.Event{}).Count(&count).Error
+
+		return err == nil && count < int64(expired)
+	}, 10*time.Second, 10*time.Millisecond)
+
+	event := &database.Event{
+		WebhookID:    webhookID,
+		EntrypointID: uuid.New().String(),
+		Method:       http.MethodPost,
+	}
+	require.NoError(t, db.Create(event).Error)
+
+	assert.Positive(t, countExpired(),
+		"the event was stored only after the whole prune")
+
+	<-pruned
+
+	assert.Zero(t, countExpired())
+
+	var stored database.Event
+
+	require.NoError(t, db.First(&stored, "id = ?", event.ID).Error)
+}
+
+// TestRetentionReaper_StopDuringPruneLeavesTheRest verifies that
+// stopping the reaper during a prune of several batches returns
+// between two batches, well inside the stop timeout, leaving the
+// remaining expired events for the next sweep, and that the totals
+// match the rows left.
+func TestRetentionReaper_StopDuringPruneLeavesTheRest(t *testing.T) {
+	t.Parallel()
+
+	env := setupRetentionTest(t)
+
+	webhookID := createWebhook(t, env.mainDB.DB(), 30)
+
+	db, err := env.mgr.GetDB(webhookID)
+	require.NoError(t, err)
+
+	// Two batches and one more of expired events, a few of them with a
+	// delivered and a failed delivery for the target totals to count.
+	// Most carry nothing else, to keep the test quick.
+	const withDeliveries = 10
+
+	expiredAt := time.Now().Add(-40 * 24 * time.Hour)
+	delivered, failed := uuid.New().String(), uuid.New().String()
+	seedExpiredEvents(t, db, webhookID, withDeliveries, expiredAt,
+		delivered, failed)
+	seedBareEvents(t, db, webhookID,
+		2*database.ExportReapBatchSize+1-withDeliveries, expiredAt)
+
+	n := int64(2*database.ExportReapBatchSize + 1)
+	require.NoError(t, database.AddEventTotals(db, database.EventTotals{
+		Events: n,
+	}))
+	require.NoError(t, database.AddTargetTotals(db, database.TargetTotals{
+		TargetID: delivered, Deliveries: withDeliveries,
+		Delivered: withDeliveries,
+	}))
+	require.NoError(t, database.AddTargetTotals(db, database.TargetTotals{
+		TargetID: failed, Deliveries: withDeliveries,
+		Failed: withDeliveries,
+	}))
+
+	env.reaper.ExportSetInterval(time.Millisecond)
+	env.reaper.ExportStart()
+
+	// Stop once the first batch is deleted. The stop lands in the pause
+	// after it, or at worst during the second batch, so at least the
+	// last event is left.
+	require.Eventually(t, func() bool {
+		var count int64
+
+		err := db.Model(&database.Event{}).Count(&count).Error
+
+		return err == nil && count < n
+	}, 10*time.Second, 10*time.Millisecond)
+
+	// The app's stop timeout.
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	require.NoError(t, env.reaper.ExportStop(ctx))
+
+	var events int64
+
+	require.NoError(t, db.Model(&database.Event{}).Count(&events).Error)
+	assert.Positive(t, events, "the stop waited for the whole prune")
+
+	eventTotals := readEventTotals(t, db)
+	assert.Equal(t, events, eventTotals.Events-eventTotals.EventsRemoved)
+
+	targetTotals := readTargetTotals(t, db)
+	require.Len(t, targetTotals, 2)
+
+	for target, totals := range targetTotals {
+		var deliveries, failures int64
+
+		require.NoError(t, db.Model(&database.Delivery{}).
+			Where("target_id = ?", target).
+			Count(&deliveries).Error)
+		require.NoError(t, db.Model(&database.Delivery{}).
+			Where("target_id = ? AND status = ?",
+				target, database.DeliveryStatusFailed).
+			Count(&failures).Error)
+
+		assert.Equal(t, deliveries,
+			totals.Deliveries-totals.DeliveriesRemoved, target)
+		assert.Equal(t, failures, totals.Failed-totals.FailedRemoved,
+			target)
+	}
+}

internal/database/webhook_db_manager.go

@@ -35,7 +35,8 @@ var errInvalidCachedDBType = errors.New(
 
 // WebhookDBManager manages per-webhook SQLite database files
 // for event storage. Each webhook gets its own dedicated
-// database containing Events, Deliveries, and DeliveryResults.
+// database containing Events, Deliveries, DeliveryResults and the
+// running totals of them (EventTotals, TargetTotals).
 // Database connections are opened lazily and cached.
 type WebhookDBManager struct {
 	dataDir string
@@ -295,6 +296,7 @@ func (m *WebhookDBManager) openDB(
 	// Run migrations for event-tier models only
 	err = db.AutoMigrate(
 		&Event{}, &Delivery{}, &DeliveryResult{},
+		&EventTotals{}, &TargetTotals{},
 	)
 	if err != nil {
 		_ = sqlDB.Close()
@@ -305,6 +307,18 @@ func (m *WebhookDBManager) openDB(
 		)
 	}
 
+	// A new database gets its row of event totals, all zero. Target
+	// totals rows are created by the first delivery to each target.
+	err = db.FirstOrCreate(&EventTotals{}).Error
+	if err != nil {
+		_ = sqlDB.Close()
+
+		return nil, fmt.Errorf(
+			"creating event totals for webhook database %s: %w",
+			webhookID, err,
+		)
+	}
+
 	m.log.Info(
 		"opened per-webhook database",
 		"webhook_id", webhookID,

internal/delivery/delivery_totals_test.go

@@ -0,0 +1,177 @@
+package delivery_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"gorm.io/gorm"
+	"sneak.berlin/go/webhooker/internal/database"
+)
+
+// targetTotals reads one target's totals from a webhook database, all
+// zero when it has no row.
+func targetTotals(
+	t *testing.T, db *gorm.DB, targetID string,
+) database.TargetTotals {
+	t.Helper()
+
+	var rows []database.TargetTotals
+
+	require.NoError(t, db.Where("target_id = ?", targetID).
+		Find(&rows).Error)
+
+	if len(rows) == 0 {
+		return database.TargetTotals{TargetID: targetID}
+	}
+
+	return rows[0]
+}
+
+// TestUpdateDeliveryStatus_FinishTimeAndTargetTotals pins what a status
+// write records for the webhook page's statistics: the time a delivery
+// finished, set only when it becomes delivered or failed, and one more
+// on its target's delivered or failed total.
+func TestUpdateDeliveryStatus_FinishTimeAndTargetTotals(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		status    database.DeliveryStatus
+		finished  bool
+		delivered int64
+		failed    int64
+	}{
+		{database.DeliveryStatusRetrying, false, 0, 0},
+		{database.DeliveryStatusDelivered, true, 1, 0},
+		{database.DeliveryStatusFailed, true, 0, 1},
+	}
+
+	for _, tt := range tests {
+		t.Run(string(tt.status), func(t *testing.T) {
+			t.Parallel()
+
+			db := testWebhookDB(t)
+			e := testEngine(t, 1)
+			event := seedEvent(t, db, `{}`)
+			targetID := uuid.New().String()
+			d := seedDelivery(
+				t, db, event.ID, targetID,
+				database.DeliveryStatusPending,
+			)
+
+			before := time.Now()
+
+			require.NoError(t, e.ExportUpdateDeliveryStatus(
+				db, &d, tt.status,
+			))
+
+			var stored database.Delivery
+
+			require.NoError(t, db.First(&stored, "id = ?", d.ID).Error)
+			assert.Equal(t, tt.status, stored.Status)
+
+			if tt.finished {
+				require.NotNil(t, stored.FinishedAt)
+				assert.False(t, stored.FinishedAt.Before(before))
+			} else {
+				assert.Nil(t, stored.FinishedAt)
+			}
+
+			assert.Equal(t, database.TargetTotals{
+				TargetID:  targetID,
+				Delivered: tt.delivered,
+				Failed:    tt.failed,
+			}, targetTotals(t, db, targetID))
+		})
+	}
+}
+
+// TestUpdateDeliveryStatus_DeletedDeliveryIsNotCounted covers a
+// delivery retention deleted while the engine still held it. Failing
+// it afterwards writes no row, so it adds no failure either: retention
+// has already counted what it removed.
+func TestUpdateDeliveryStatus_DeletedDeliveryIsNotCounted(t *testing.T) {
+	t.Parallel()
+
+	db := testWebhookDB(t)
+	e := testEngine(t, 1)
+	event := seedEvent(t, db, `{}`)
+	targetID := uuid.New().String()
+	d := seedDelivery(
+		t, db, event.ID, targetID,
+		database.DeliveryStatusRetrying,
+	)
+
+	require.NoError(t, db.Unscoped().
+		Delete(&database.Delivery{}, "id = ?", d.ID).Error)
+
+	require.NoError(t, e.ExportUpdateDeliveryStatus(
+		db, &d, database.DeliveryStatusFailed,
+	))
+
+	assert.Equal(t, database.TargetTotals{TargetID: targetID},
+		targetTotals(t, db, targetID))
+}
+
+// TestUpdateDeliveryStatus_FinishedDeliveryIsNotSettledAgain covers a
+// delivery settled a second time, as recovery can do when a worker has
+// settled it since recovery read it. Neither status writes over the
+// first, and the totals do not move.
+func TestUpdateDeliveryStatus_FinishedDeliveryIsNotSettledAgain(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	finished := []database.DeliveryStatus{
+		database.DeliveryStatusDelivered,
+		database.DeliveryStatusFailed,
+	}
+
+	for _, first := range finished {
+		t.Run(string(first), func(t *testing.T) {
+			t.Parallel()
+
+			db := testWebhookDB(t)
+			e := testEngine(t, 1)
+			event := seedEvent(t, db, `{}`)
+			targetID := uuid.New().String()
+			d := seedDelivery(
+				t, db, event.ID, targetID,
+				database.DeliveryStatusRetrying,
+			)
+
+			// The delivery as recovery read it, before the worker
+			// settled it.
+			readBefore := d
+
+			require.NoError(t, e.ExportUpdateDeliveryStatus(
+				db, &d, first,
+			))
+
+			var settled database.Delivery
+
+			require.NoError(t, db.First(&settled, "id = ?", d.ID).Error)
+			require.NotNil(t, settled.FinishedAt)
+
+			totals := targetTotals(t, db, targetID)
+
+			for _, again := range finished {
+				stale := readBefore
+
+				require.NoError(t, e.ExportUpdateDeliveryStatus(
+					db, &stale, again,
+				))
+			}
+
+			var stored database.Delivery
+
+			require.NoError(t, db.First(&stored, "id = ?", d.ID).Error)
+			assert.Equal(t, first, stored.Status)
+			require.NotNil(t, stored.FinishedAt)
+			assert.True(t, settled.FinishedAt.Equal(*stored.FinishedAt))
+			assert.Equal(t, totals, targetTotals(t, db, targetID))
+		})
+	}
+}

internal/delivery/engine.go

@@ -531,6 +531,11 @@ func (e *Engine) processRetryTask(
 		return
 	}
 
+	// Set before anything below can fail the delivery: the failure is
+	// added to this target's totals.
+	d.EventID = task.EventID
+	d.TargetID = task.TargetID
+
 	if d.Status != database.DeliveryStatusRetrying {
 		e.log.Debug(
 			"skipping retry for delivery "+
@@ -562,8 +567,6 @@ func (e *Engine) processRetryTask(
 	}
 
 	target := buildTargetFromTask(task)
-	d.EventID = task.EventID
-	d.TargetID = task.TargetID
 	d.Event = event
 	d.Target = target
 
@@ -1554,8 +1557,9 @@ func (e *Engine) updateDeliveryStatus(
 	targetType database.TargetType,
 	status database.DeliveryStatus,
 ) error {
-	err := webhookDB.Model(d).
+	err := webhookDB.Transaction(func(tx *gorm.DB) error {
-		Update("status", status).Error
+		return writeDeliveryStatus(tx, d, status)
+	})
 	if err != nil {
 		return fmt.Errorf(
 			"updating delivery %s to status %s: %w",
@@ -1574,6 +1578,43 @@ func (e *Engine) updateDeliveryStatus(
 	return nil
 }
 
+// writeDeliveryStatus writes a delivery's new status. A delivery that
+// becomes delivered or failed also gets the time it finished, and is
+// added to its target's delivered or failed total. That write changes
+// only a delivery not yet delivered or failed, and the total moves
+// only when it changed a row: retention may have deleted the delivery
+// while the engine was working on it, and a recovery path may settle
+// a delivery that a worker has already settled.
+func writeDeliveryStatus(
+	tx *gorm.DB,
+	d *database.Delivery,
+	status database.DeliveryStatus,
+) error {
+	if !status.Terminal() {
+		return tx.Model(d).Update("status", status).Error
+	}
+
+	res := tx.Model(d).
+		Where("status NOT IN ?", []database.DeliveryStatus{
+			database.DeliveryStatusDelivered,
+			database.DeliveryStatusFailed,
+		}).
+		Updates(map[string]any{
+			"status":      status,
+			"finished_at": time.Now(),
+		})
+	if res.Error != nil || res.RowsAffected == 0 {
+		return res.Error
+	}
+
+	add := database.TargetTotals{TargetID: d.TargetID, Delivered: 1}
+	if status == database.DeliveryStatusFailed {
+		add = database.TargetTotals{TargetID: d.TargetID, Failed: 1}
+	}
+
+	return database.AddTargetTotals(tx, add)
+}
+
 // settleStatus moves a delivery to its outcome status and reports a
 // failed write through bookkeepingFailed, which leaves the row
 // recoverable. It exists so the target call sites read as one

internal/delivery/engine_test.go

@@ -57,7 +57,10 @@ func testWebhookDB(t *testing.T) *gorm.DB {
 		&database.Event{},
 		&database.Delivery{},
 		&database.DeliveryResult{},
+		&database.EventTotals{},
+		&database.TargetTotals{},
 	))
+	require.NoError(t, db.Create(&database.EventTotals{}).Error)
 
 	return db
 }

internal/delivery/export_test.go

@@ -150,6 +150,16 @@ func (e *Engine) ExportDeliverSlack(
 	)
 }
 
+// ExportUpdateDeliveryStatus exposes updateDeliveryStatus. It passes no
+// target type, so no metric moves.
+func (e *Engine) ExportUpdateDeliveryStatus(
+	webhookDB *gorm.DB,
+	d *database.Delivery,
+	status database.DeliveryStatus,
+) error {
+	return e.updateDeliveryStatus(webhookDB, d, "", status)
+}
+
 // ExportProcessNewTask exposes processNewTask.
 func (e *Engine) ExportProcessNewTask(
 	ctx context.Context, task *Task,

internal/delivery/terminal_state_test.go

@@ -418,6 +418,38 @@ func TestProcessRetryTask_TargetDeleted_MakesNoAttempt(
 	assert.Zero(t, s.Engine.ExportInflightHeld())
 }
 
+// TestProcessRetryTask_TargetDeleted_CountsFailureOnTarget verifies
+// that the failure of a retry abandoned because its target is gone is
+// added to that target's own totals, not to a row with no target.
+func TestProcessRetryTask_TargetDeleted_CountsFailureOnTarget(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	s := newISetup(t)
+
+	var hits atomic.Int64
+
+	task, targetID := tRetryChainSetup(
+		t, s, "gone-counted", &hits,
+	)
+
+	require.NoError(t, s.MainDB.Delete(
+		&database.Target{}, "id = ?", targetID,
+	).Error)
+
+	s.Engine.ExportProcessRetryTask(
+		context.Background(), &task,
+	)
+
+	var rows []database.TargetTotals
+
+	require.NoError(t, s.WebhookDB.Find(&rows).Error)
+	assert.Equal(t, []database.TargetTotals{
+		{TargetID: targetID, Failed: 1},
+	}, rows)
+}
+
 // TestProcessRetryTask_TargetPresent_StillDelivers is the guard's
 // mutation check: a liveness check that refused every retry would pass
 // the test above and break every retry there is.

internal/handlers/auth.go

@@ -36,7 +36,7 @@ func (h *Handlers) HandleLoginSubmit() http.HandlerFunc {
 		err := r.ParseForm()
 		if err != nil {
 			h.log.Error("failed to parse form", "error", err)
-			h.renderError(w, r, http.StatusBadRequest)
+			http.Error(w, "Bad request", http.StatusBadRequest)
 
 			return
 		}
@@ -166,7 +166,11 @@ func (h *Handlers) authenticateUser(
 
 	valid, err := database.VerifyPassword(password, user.Password)
 	if err != nil {
-		h.serverError(w, r, "failed to verify password", err)
+		h.log.Error("failed to verify password", "error", err)
+		http.Error(
+			w, "Internal server error",
+			http.StatusInternalServerError,
+		)
 
 		return user, err
 	}
@@ -238,14 +242,24 @@ func (h *Handlers) createAuthenticatedSession(
 ) error {
 	oldSess, err := h.session.Get(r)
 	if err != nil {
-		h.serverError(w, r, "failed to get session", err)
+		h.log.Error("failed to get session", "error", err)
+		http.Error(
+			w, "Internal server error",
+			http.StatusInternalServerError,
+		)
 
 		return err
 	}
 
 	sess, err := h.session.Regenerate(r, w, oldSess)
 	if err != nil {
-		h.serverError(w, r, "failed to regenerate session", err)
+		h.log.Error(
+			"failed to regenerate session", "error", err,
+		)
+		http.Error(
+			w, "Internal server error",
+			http.StatusInternalServerError,
+		)
 
 		return err
 	}
@@ -254,7 +268,11 @@ func (h *Handlers) createAuthenticatedSession(
 
 	err = h.session.Save(r, w, sess)
 	if err != nil {
-		h.serverError(w, r, "failed to save session", err)
+		h.log.Error("failed to save session", "error", err)
+		http.Error(
+			w, "Internal server error",
+			http.StatusInternalServerError,
+		)
 
 		return err
 	}

internal/handlers/delivery_replay.go

@@ -105,7 +105,9 @@ func (h *Handlers) HandleDeliveryReplay() http.HandlerFunc {
 		// middleware, which runs before CSRF parses the form.
 		err := r.ParseForm()
 		if err != nil {
-			h.renderError(w, r, http.StatusBadRequest)
+			http.Error(
+				w, "Bad request", http.StatusBadRequest,
+			)
 
 			return
 		}
@@ -122,14 +124,14 @@ func (h *Handlers) replayDelivery(
 	webhook database.Webhook,
 ) {
 	if !h.dbMgr.DBExists(webhook.ID) {
-		h.renderError(w, r, http.StatusNotFound)
+		http.NotFound(w, r)
 
 		return
 	}
 
 	webhookDB, err := h.dbMgr.GetDB(webhook.ID)
 	if err != nil {
-		h.serverError(w, r, "failed to get webhook database", err)
+		h.serverError(w, "failed to get webhook database", err)
 
 		return
 	}
@@ -171,7 +173,7 @@ func (h *Handlers) loadReplaySource(
 			&original, "id = ?", chi.URLParam(r, "deliveryID"),
 		).Error
 	if err != nil {
-		h.renderError(w, r, http.StatusNotFound)
+		http.NotFound(w, r)
 
 		return nil, false
 	}
@@ -193,7 +195,7 @@ func (h *Handlers) queueReplay(
 	)
 	if err != nil {
 		h.serverError(
-			w, r, "failed to count in-flight deliveries", err,
+			w, "failed to count in-flight deliveries", err,
 		)
 
 		return
@@ -210,7 +212,7 @@ func (h *Handlers) queueReplay(
 	err = webhookDB.
 		First(&event, "id = ?", original.EventID).Error
 	if err != nil {
-		h.serverError(w, r, "failed to load event for replay", err)
+		h.serverError(w, "failed to load event for replay", err)
 
 		return
 	}
@@ -220,7 +222,7 @@ func (h *Handlers) queueReplay(
 	)
 	if err != nil {
 		h.serverError(
-			w, r, "failed to create replay delivery", err,
+			w, "failed to create replay delivery", err,
 		)
 
 		return
@@ -297,8 +299,9 @@ func countInFlightDeliveries(
 	return count, err
 }
 
-// createReplayDelivery writes the new pending delivery row and returns
+// createReplayDelivery writes the new pending delivery row, adds it to
-// the task that carries it to the delivery engine.
+// its target's totals in the same transaction, and returns the task
+// that carries it to the delivery engine.
 //
 // The row is written with associations omitted, and neither Event nor
 // Target is populated on it: GORM's SaveBeforeAssociations would
@@ -317,7 +320,16 @@ func createReplayDelivery(
 		Status:   database.DeliveryStatusPending,
 	}
 
-	err := webhookDB.Omit(clause.Associations).Create(dlv).Error
+	err := webhookDB.Transaction(func(tx *gorm.DB) error {
+		err := tx.Omit(clause.Associations).Create(dlv).Error
+		if err != nil {
+			return err
+		}
+
+		return database.AddTargetTotals(tx, database.TargetTotals{
+			TargetID: dlv.TargetID, Deliveries: 1,
+		})
+	})
 	if err != nil {
 		return delivery.Task{}, err
 	}

internal/handlers/error_page_test.go

@@ -1,53 +0,0 @@
-package handlers_test
-
-import (
-	"context"
-	"html/template"
-	"net/http"
-	"net/http/httptest"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"sneak.berlin/go/webhooker/internal/handlers"
-)
-
-// TestErrorPage_RenderFailureKeepsStatus proves that an error page
-// which cannot render answers with the status it was reporting, as
-// plain text, and is not attempted again: a page whose own render
-// fails reaches the error page, and the error page failing as well
-// ends there with the 500.
-func TestErrorPage_RenderFailureKeepsStatus(t *testing.T) {
-	t.Parallel()
-
-	var h *handlers.Handlers
-
-	app := newTestApp(t, &h)
-	app.RequireStart()
-
-	t.Cleanup(app.RequireStop)
-
-	// .Status is an int, so asking it for a field fails the render.
-	failing := `{{.Status.Missing}}`
-	h.AddTemplateForTest("error.html", template.Must(
-		template.New("error").Parse(failing),
-	))
-	h.AddTemplateForTest("failing.html", template.Must(
-		template.New("failing").Parse(`{{.Data.Missing}}`),
-	))
-
-	req := httptest.NewRequestWithContext(
-		context.Background(), http.MethodGet, "/", nil,
-	)
-
-	w := httptest.NewRecorder()
-	h.HandleErrorPage(http.StatusNotFound).ServeHTTP(w, req)
-
-	assert.Equal(t, http.StatusNotFound, w.Code)
-	assert.Equal(t, "Not Found\n", w.Body.String())
-
-	w = httptest.NewRecorder()
-	h.RenderTemplateForTest(w, req, "failing.html", 0)
-
-	assert.Equal(t, http.StatusInternalServerError, w.Code)
-	assert.Equal(t, "Internal Server Error\n", w.Body.String())
-}

internal/handlers/event_body.go

@@ -52,7 +52,7 @@ func (h *Handlers) HandleEventBodyDownload() http.HandlerFunc {
 		// steered by a client.
 		eventID, err := uuid.Parse(chi.URLParam(r, "eventID"))
 		if err != nil {
-			h.renderError(w, r, http.StatusNotFound)
+			http.NotFound(w, r)
 
 			return
 		}
@@ -103,21 +103,21 @@ func (h *Handlers) serveEventBody(
 	eventID string,
 ) {
 	if !h.dbMgr.DBExists(webhook.ID) {
-		h.renderError(w, r, http.StatusNotFound)
+		http.NotFound(w, r)
 
 		return
 	}
 
 	webhookDB, err := h.dbMgr.GetDB(webhook.ID)
 	if err != nil {
-		h.serverError(w, r, "failed to get webhook database", err)
+		h.serverError(w, "failed to get webhook database", err)
 
 		return
 	}
 
 	body, found, err := eventBody(webhookDB, webhook.ID, eventID)
 	if err != nil {
-		h.serverError(w, r, "failed to read event body", err)
+		h.serverError(w, "failed to read event body", err)
 
 		return
 	}
@@ -130,7 +130,7 @@ func (h *Handlers) serveEventBody(
 	// row and the whole body is served, or it does not and the
 	// response is a clean 404.
 	if !found {
-		h.renderError(w, r, http.StatusNotFound)
+		http.NotFound(w, r)
 
 		return
 	}

internal/handlers/event_resubmit.go

@@ -99,7 +99,7 @@ func (h *Handlers) HandleEventResubmit() http.HandlerFunc {
 		// middleware, which runs before CSRF parses the form.
 		err := r.ParseForm()
 		if err != nil {
-			h.renderError(w, r, http.StatusBadRequest)
+			http.Error(w, "Bad request", http.StatusBadRequest)
 
 			return
 		}
@@ -120,20 +120,20 @@ func (h *Handlers) resubmitEvent(
 	// alphabet rather than from the request.
 	eventID, err := uuid.Parse(chi.URLParam(r, "eventID"))
 	if err != nil {
-		h.renderError(w, r, http.StatusNotFound)
+		http.NotFound(w, r)
 
 		return
 	}
 
 	if !h.dbMgr.DBExists(webhook.ID) {
-		h.renderError(w, r, http.StatusNotFound)
+		http.NotFound(w, r)
 
 		return
 	}
 
 	webhookDB, err := h.dbMgr.GetDB(webhook.ID)
 	if err != nil {
-		h.serverError(w, r, "failed to get webhook database", err)
+		h.serverError(w, "failed to get webhook database", err)
 
 		return
 	}
@@ -147,7 +147,7 @@ func (h *Handlers) resubmitEvent(
 		webhookDB, webhook.ID, eventID.String(),
 	)
 	if err != nil {
-		h.serverError(w, r, "failed to load event to resubmit", err)
+		h.serverError(w, "failed to load event to resubmit", err)
 
 		return
 	}
@@ -155,7 +155,7 @@ func (h *Handlers) resubmitEvent(
 	// A miss is a 404 whether the event was reaped, belongs to
 	// another webhook, or never existed.
 	if !found {
-		h.renderError(w, r, http.StatusNotFound)
+		http.NotFound(w, r)
 
 		return
 	}
@@ -207,7 +207,7 @@ func (h *Handlers) queueResubmit(
 	// inactive one is skipped rather than refused.
 	targets, err := h.loadActiveTargets(webhook.ID)
 	if err != nil {
-		h.serverError(w, r, "failed to query targets", err)
+		h.serverError(w, "failed to query targets", err)
 
 		return
 	}
@@ -225,7 +225,7 @@ func (h *Handlers) queueResubmit(
 		targets,
 	)
 	if err != nil {
-		h.serverError(w, r, "failed to store resubmitted event", err)
+		h.serverError(w, "failed to store resubmitted event", err)
 
 		return
 	}

internal/handlers/export_test.go

@@ -1,12 +1,12 @@
 package handlers
 
 import (
-	"context"
 	"html/template"
 	"log/slog"
 	"net/http"
-	"net/http/httptest"
+	"time"
 
+	"gorm.io/gorm"
 	"sneak.berlin/go/webhooker/internal/database"
 )
 
@@ -65,18 +65,33 @@ func (s *Handlers) LoadEventLogViewsForTest(
 	page int,
 ) []EventLogView {
 	views, _, _ := s.loadEventsWithDeliveries(
-		w, newRequestForTest(), webhook, nil, page,
+		w, webhook, nil, page,
 	)
 
 	return views
 }
 
-// newRequestForTest is the request the helpers here pass on for
+// WebhookStatsForTest returns the figures the statistics pane on a
-// callers that have none: it is used only to render the error page.
+// webhook's page shows, from the webhook's entrypoints and targets
-func newRequestForTest() *http.Request {
+// loaded as that page loads them.
-	return httptest.NewRequestWithContext(
+func (s *Handlers) WebhookStatsForTest(webhookID string) *WebhookStats {
-		context.Background(), http.MethodGet, "/", nil,
+	var entrypoints []database.Entrypoint
-	)
+
+	s.db.DB().Where("webhook_id = ?", webhookID).Find(&entrypoints)
+
+	var targets []database.Target
+
+	s.db.DB().Where("webhook_id = ?", webhookID).Find(&targets)
+
+	return s.loadWebhookStats(webhookID, entrypoints, targets)
+}
+
+// FinishedByTargetForTest exposes finishedByTarget for use in the
+// handlers_test package.
+func FinishedByTargetForTest(
+	webhookDB *gorm.DB, since time.Time,
+) ([]TargetFinished, error) {
+	return finishedByTarget(webhookDB, since)
 }
 
 // AddTemplateForTest registers a template under a page name so that
@@ -132,5 +147,5 @@ func (s *Handlers) BuildDatabaseTargetConfigForTest(
 	w http.ResponseWriter,
 	expiry string,
 ) (string, error) {
-	return s.buildDatabaseTargetConfig(w, newRequestForTest(), expiry)
+	return s.buildDatabaseTargetConfig(w, expiry)
 }

internal/handlers/handlers.go

@@ -91,18 +91,22 @@ type Handlers struct {
 
 // parsePageTemplate parses a page-specific template set from the
 // embedded FS. Each page template is combined with the shared
-// base, htmlheader, and navbar templates. The page file must be
+// base, htmlheader, and navbar templates, and with any further files
-// listed first so that its root action ({{template "base" .}})
+// the page includes. The page file must be listed first so that its
-// becomes the template set's entry point.
+// root action ({{template "base" .}}) becomes the template set's entry
-func parsePageTemplate(pageFile string) *template.Template {
+// point.
+func parsePageTemplate(
+	pageFile string, included ...string,
+) *template.Template {
+	files := append([]string{
+		pageFile,
+		"base.html",
+		"htmlheader.html",
+		"navbar.html",
+	}, included...)
+
 	return template.Must(
-		template.ParseFS(
+		template.ParseFS(templates.Templates, files...),
-			templates.Templates,
-			pageFile,
-			"base.html",
-			"htmlheader.html",
-			"navbar.html",
-		),
 	)
 }
 
@@ -131,11 +135,10 @@ func New(
 		"profile.html":       parsePageTemplate("profile.html"),
 		"sources_list.html":  parsePageTemplate("sources_list.html"),
 		"sources_new.html":   parsePageTemplate("sources_new.html"),
-		"source_detail.html": parsePageTemplate("source_detail.html"),
+		"source_detail.html": parsePageTemplate("source_detail.html", "webhook_stats.html"),
 		"source_edit.html":   parsePageTemplate("source_edit.html"),
 		"source_logs.html":   parsePageTemplate("source_logs.html"),
 		"target_edit.html":   parsePageTemplate("target_edit.html"),
-		"error.html":         parsePageTemplate("error.html"),
 	}
 
 	lc.Append(fx.Hook{
@@ -147,16 +150,6 @@ func New(
 	return s, nil
 }
 
-// HandleErrorPage returns a handler that answers every request with
-// the error page for status. The router uses it for unknown paths, the
-// CSRF middleware for a refused form, and each admin page route
-// group's recoverer for a panic.
-func (s *Handlers) HandleErrorPage(status int) http.HandlerFunc {
-	return func(w http.ResponseWriter, r *http.Request) {
-		s.renderError(w, r, status)
-	}
-}
-
 func (s *Handlers) respondJSON(
 	w http.ResponseWriter,
 	_ *http.Request,
@@ -174,76 +167,15 @@ func (s *Handlers) respondJSON(
 	}
 }
 
-// serverError logs an error and answers with the 500 error page.
+// serverError logs an error and sends a 500 response.
 func (s *Handlers) serverError(
-	w http.ResponseWriter, r *http.Request, msg string, err error,
+	w http.ResponseWriter, msg string, err error,
 ) {
 	s.log.Error(msg, "error", err)
-	s.renderError(w, r, http.StatusInternalServerError)
+	http.Error(
-}
+		w, "Internal server error",
-
+		http.StatusInternalServerError,
-// renderError answers with status and the error page: the normal
+	)
-// layout, one fixed line explaining the status, and a link back to the
-// webhook list, or to sign-in when nobody is signed in.
-//
-// It renders the page itself rather than through renderTemplate,
-// whose own failure comes here. If the error page cannot render
-// either, the answer is the same status in plain text: never a second
-// attempt, and never a different status.
-func (s *Handlers) renderError(
-	w http.ResponseWriter,
-	r *http.Request,
-	status int,
-) {
-	// The page names the signed-in user, and some error pages are
-	// served outside the routes where NoCache runs.
-	w.Header().Set("Cache-Control", "no-store")
-
-	data := s.pageData(r, map[string]any{
-		"Status":     status,
-		"StatusText": http.StatusText(status),
-		"Message":    errorPageText(status),
-	})
-
-	var buf bytes.Buffer
-
-	err := s.templates["error.html"].Execute(&buf, data)
-	if err != nil {
-		s.log.Error("failed to render error page", "error", err)
-		http.Error(w, http.StatusText(status), status)
-
-		return
-	}
-
-	w.Header().Set("Content-Type", "text/html; charset=utf-8")
-	w.WriteHeader(status)
-
-	_, err = buf.WriteTo(w)
-	if err != nil {
-		s.log.Error("failed to write error page", "error", err)
-	}
-}
-
-// errorPageText is the line the error page shows for status. It is
-// fixed per status, so the page tells the reader no more than the
-// plain-text answers it replaced did.
-func errorPageText(status int) string {
-	switch status {
-	case http.StatusBadRequest:
-		return "The request could not be read."
-	case http.StatusForbidden:
-		return "The request was refused. If it came from a form " +
-			"left open for a long time, reload the page and try " +
-			"again."
-	case http.StatusNotFound:
-		return "There is nothing here. It may have been deleted, " +
-			"or the address may be wrong."
-	case http.StatusServiceUnavailable:
-		return "The server is busy. Please try again in a moment."
-	default: // http.StatusInternalServerError
-		return "Something went wrong on the server. Please try " +
-			"again."
-	}
 }
 
 // UserInfo represents user information for templates
@@ -296,17 +228,14 @@ func (s *Handlers) renderTemplate(
 			"template not found",
 			"template", pageTemplate,
 		)
-		s.renderError(w, r, http.StatusInternalServerError)
+		http.Error(
+			w, "Internal server error",
+			http.StatusInternalServerError,
+		)
 
 		return
 	}
 
-	s.executeTemplate(w, r, tmpl, s.pageData(r, data))
-}
-
-// pageData adds the fields the shared layout renders to a page's own
-// data.
-func (s *Handlers) pageData(r *http.Request, data any) any {
 	userInfo := s.getUserInfo(r)
 	csrfToken := middleware.CSRFToken(r)
 
@@ -320,16 +249,19 @@ func (s *Handlers) pageData(r *http.Request, data any) any {
 		m["User"] = userInfo
 		m["CSRFToken"] = csrfToken
 		m["Version"] = version
+		s.executeTemplate(w, tmpl, m)
 
-		return m
+		return
 	}
 
-	return templateDataWrapper{
+	wrapper := templateDataWrapper{
 		User:      userInfo,
 		CSRFToken: csrfToken,
 		Version:   version,
 		Data:      data,
 	}
+
+	s.executeTemplate(w, tmpl, wrapper)
 }
 
 // executeTemplate renders the template into a buffer and writes to
@@ -342,7 +274,6 @@ func (s *Handlers) pageData(r *http.Request, data any) any {
 // this reason.
 func (s *Handlers) executeTemplate(
 	w http.ResponseWriter,
-	r *http.Request,
 	tmpl *template.Template,
 	data any,
 ) {
@@ -353,7 +284,10 @@ func (s *Handlers) executeTemplate(
 		s.log.Error(
 			"failed to execute template", "error", err,
 		)
-		s.renderError(w, r, http.StatusInternalServerError)
+		http.Error(
+			w, "Internal server error",
+			http.StatusInternalServerError,
+		)
 
 		return
 	}

internal/handlers/handlers_test.go

@@ -307,14 +307,10 @@ func TestRenderTemplateMidRenderErrorSendsNoPartialBody(t *testing.T) {
 		t, http.StatusInternalServerError, w.Code,
 		"a failed render must report a 500",
 	)
-	assert.NotContains(
+	assert.Equal(
-		t, w.Body.String(), partialPageMarker,
+		t, "Internal server error\n", w.Body.String(),
 		"the response must carry no part of the aborted page",
 	)
-	assert.Contains(
-		t, w.Body.String(), "500 Internal Server Error",
-		"a failed render must answer with the error page",
-	)
 }
 
 func TestBuildDatabaseTargetConfig_Valid(t *testing.T) {

internal/handlers/profile.go

@@ -1,6 +1,7 @@
 package handlers
 
 import (
+	"context"
 	"net/http"
 
 	"github.com/go-chi/chi"
@@ -36,14 +37,14 @@ func (h *Handlers) HandlePasswordChange() http.HandlerFunc {
 		err := r.ParseForm()
 		if err != nil {
 			h.log.Error("failed to parse form", "error", err)
-			h.renderError(w, r, http.StatusBadRequest)
+			http.Error(w, "Bad request", http.StatusBadRequest)
 
 			return
 		}
 
 		successMessage, errorMessage, handled := h.applyPasswordChange(
+			r.Context(),
 			w,
-			r,
 			sessionUsername,
 			// PostFormValue, not FormValue: the credential must
 			// come from the body, never from the query string.
@@ -65,12 +66,12 @@ func (h *Handlers) HandlePasswordChange() http.HandlerFunc {
 // applyPasswordChange verifies the current password and, on success,
 // persists a fresh hash for the user, reusing the same helpers that
 // bootstrap the admin user. It returns the success and error messages
-// to display on the profile page. On an internal failure it writes the
+// to display on the profile page. On an internal failure it writes a
-// error page itself and returns handled=false, signalling the caller
+// 500 response itself and returns handled=false, signalling the caller
 // to stop without re-rendering the page.
 func (h *Handlers) applyPasswordChange(
+	ctx context.Context,
 	w http.ResponseWriter,
-	r *http.Request,
 	username, currentPassword, newPassword, confirmPassword string,
 ) (string, string, bool) {
 	// This endpoint verifies one password and hashes another, at
@@ -78,10 +79,15 @@ func (h *Handlers) applyPasswordChange(
 	// endpoint uses. The bound is per hash, not per endpoint: leaving
 	// this path outside it would leave a hole in it. The slot is held
 	// across both hashes.
-	release, ok := h.mw.BeginPasswordVerification(r.Context())
+	release, ok := h.mw.BeginPasswordVerification(ctx)
 	if !ok {
 		h.log.Warn("password verification capacity exhausted")
-		h.renderError(w, r, http.StatusServiceUnavailable)
+		http.Error(
+			w,
+			"The server is busy verifying credentials. "+
+				"Please try again.",
+			http.StatusServiceUnavailable,
+		)
 
 		return "", "", false
 	}
@@ -97,7 +103,7 @@ func (h *Handlers) applyPasswordChange(
 	).First(&user).Error
 	if err != nil {
 		h.serverError(
-			w, r, "failed to load user for password change", err,
+			w, "failed to load user for password change", err,
 		)
 
 		return "", "", false
@@ -107,7 +113,7 @@ func (h *Handlers) applyPasswordChange(
 		currentPassword, user.Password,
 	)
 	if err != nil {
-		h.serverError(w, r, "failed to verify password", err)
+		h.serverError(w, "failed to verify password", err)
 
 		return "", "", false
 	}
@@ -126,7 +132,7 @@ func (h *Handlers) applyPasswordChange(
 
 	hashedPassword, err := database.HashPassword(newPassword)
 	if err != nil {
-		h.serverError(w, r, "failed to hash new password", err)
+		h.serverError(w, "failed to hash new password", err)
 
 		return "", "", false
 	}
@@ -135,7 +141,7 @@ func (h *Handlers) applyPasswordChange(
 		"password", hashedPassword,
 	).Error
 	if err != nil {
-		h.serverError(w, r, "failed to update password", err)
+		h.serverError(w, "failed to update password", err)
 
 		return "", "", false
 	}
@@ -156,7 +162,7 @@ func (h *Handlers) profileOwnerOrDeny(
 ) (string, string, bool) {
 	requestedUsername := chi.URLParam(r, "username")
 	if requestedUsername == "" {
-		h.renderError(w, r, http.StatusNotFound)
+		http.NotFound(w, r)
 
 		return "", "", false
 	}
@@ -166,7 +172,7 @@ func (h *Handlers) profileOwnerOrDeny(
 	// unexpected retrieval error.
 	sess, err := h.session.Get(r)
 	if err != nil {
-		h.serverError(w, r, "failed to get session", err)
+		h.serverError(w, "failed to get session", err)
 
 		return "", "", false
 	}
@@ -174,7 +180,10 @@ func (h *Handlers) profileOwnerOrDeny(
 	sessionUsername, ok := h.session.GetUsername(sess)
 	if !ok {
 		h.log.Error("authenticated session missing username")
-		h.renderError(w, r, http.StatusInternalServerError)
+		http.Error(
+			w, "Internal server error",
+			http.StatusInternalServerError,
+		)
 
 		return "", "", false
 	}
@@ -182,14 +191,17 @@ func (h *Handlers) profileOwnerOrDeny(
 	sessionUserID, ok := h.session.GetUserID(sess)
 	if !ok {
 		h.log.Error("authenticated session missing user ID")
-		h.renderError(w, r, http.StatusInternalServerError)
+		http.Error(
+			w, "Internal server error",
+			http.StatusInternalServerError,
+		)
 
 		return "", "", false
 	}
 
 	// Only allow users to act on their own profile.
 	if requestedUsername != sessionUsername {
-		h.renderError(w, r, http.StatusForbidden)
+		http.Error(w, "Forbidden", http.StatusForbidden)
 
 		return "", "", false
 	}

internal/handlers/profile_test.go

@@ -128,9 +128,7 @@ func TestUserRoute_Unauthenticated_RedirectedByMiddleware(t *testing.T) {
 
 	var sess *session.Session
 
-	var h *handlers.Handlers
+	app := newTestApp(t, &log, &cfg, &sess)
-
-	app := newTestApp(t, &log, &cfg, &sess, &h)
 	app.RequireStart()
 
 	t.Cleanup(app.RequireStop)
@@ -141,7 +139,7 @@ func TestUserRoute_Unauthenticated_RedirectedByMiddleware(t *testing.T) {
 
 	router := chi.NewRouter()
 	router.Route("/user/{username}", func(r chi.Router) {
-		r.Use(mw.CSRF(h.HandleErrorPage(http.StatusForbidden)))
+		r.Use(mw.CSRF())
 		r.Use(mw.RequireAuth())
 		r.Get("/", func(w http.ResponseWriter, _ *http.Request) {
 			handlerReached = true

internal/handlers/source_management.go

@@ -149,7 +149,13 @@ func (h *Handlers) HandleSourceList() http.HandlerFunc {
 			"user_id = ?", userID,
 		).Order("created_at DESC").Find(&webhooks).Error
 		if err != nil {
-			h.serverError(w, r, "failed to list webhooks", err)
+			h.log.Error(
+				"failed to list webhooks", "error", err,
+			)
+			http.Error(
+				w, "Internal server error",
+				http.StatusInternalServerError,
+			)
 
 			return
 		}
@@ -243,7 +249,9 @@ func (h *Handlers) HandleSourceCreateSubmit() http.HandlerFunc {
 		// middleware, which runs before CSRF parses the form.
 		err := r.ParseForm()
 		if err != nil {
-			h.renderError(w, r, http.StatusBadRequest)
+			http.Error(
+				w, "Bad request", http.StatusBadRequest,
+			)
 
 			return
 		}
@@ -303,7 +311,7 @@ func (h *Handlers) createWebhookWithEntrypoint(
 
 	err := h.commitWebhook(webhook)
 	if err != nil {
-		h.serverError(w, r, "failed to create webhook", err)
+		h.serverError(w, "failed to create webhook", err)
 
 		return
 	}
@@ -380,7 +388,7 @@ func (h *Handlers) HandleSourceDetail() http.HandlerFunc {
 			"id = ? AND user_id = ?", sourceID, userID,
 		).First(&webhook).Error
 		if err != nil {
-			h.renderError(w, r, http.StatusNotFound)
+			http.NotFound(w, r)
 
 			return
 		}
@@ -412,7 +420,7 @@ func (h *Handlers) renderSourceDetail(
 	if h.dbMgr.DBExists(webhook.ID) {
 		webhookDB, err := h.dbMgr.GetDB(webhook.ID)
 		if err != nil {
-			h.serverError(w, r, "failed to get webhook database", err)
+			h.serverError(w, "failed to get webhook database", err)
 
 			return
 		}
@@ -421,7 +429,7 @@ func (h *Handlers) renderSourceDetail(
 			webhookDB, webhook.ID, singleHTTPTargetID(targets),
 		)
 		if err != nil {
-			h.serverError(w, r, "failed to load recent events", err)
+			h.serverError(w, "failed to load recent events", err)
 
 			return
 		}
@@ -449,6 +457,7 @@ func (h *Handlers) renderSourceDetail(
 		"Targets":     delivery.NewTargetViews(targets),
 		"Events":      events,
 		"BaseURL":     baseURL,
+		"Stats":       h.loadWebhookStats(webhook.ID, entrypoints, targets),
 	}
 
 	h.renderTemplate(w, r, "source_detail.html", data)
@@ -474,7 +483,7 @@ func (h *Handlers) HandleSourceEdit() http.HandlerFunc {
 			"id = ? AND user_id = ?", sourceID, userID,
 		).First(&webhook).Error
 		if err != nil {
-			h.renderError(w, r, http.StatusNotFound)
+			http.NotFound(w, r)
 
 			return
 		}
@@ -509,7 +518,7 @@ func (h *Handlers) HandleSourceEditSubmit() http.HandlerFunc {
 			"id = ? AND user_id = ?", sourceID, userID,
 		).First(&webhook).Error
 		if err != nil {
-			h.renderError(w, r, http.StatusNotFound)
+			http.NotFound(w, r)
 
 			return
 		}
@@ -518,7 +527,9 @@ func (h *Handlers) HandleSourceEditSubmit() http.HandlerFunc {
 		// middleware, which runs before CSRF parses the form.
 		err = r.ParseForm()
 		if err != nil {
-			h.renderError(w, r, http.StatusBadRequest)
+			http.Error(
+				w, "Bad request", http.StatusBadRequest,
+			)
 
 			return
 		}
@@ -572,7 +583,7 @@ func (h *Handlers) applyWebhookEdit(
 
 	err := h.db.DB().Save(webhook).Error
 	if err != nil {
-		h.serverError(w, r, "failed to update webhook", err)
+		h.serverError(w, "failed to update webhook", err)
 
 		return
 	}
@@ -602,7 +613,7 @@ func (h *Handlers) HandleSourceDelete() http.HandlerFunc {
 			"id = ? AND user_id = ?", sourceID, userID,
 		).First(&webhook).Error
 		if err != nil {
-			h.renderError(w, r, http.StatusNotFound)
+			http.NotFound(w, r)
 
 			return
 		}
@@ -629,7 +640,7 @@ func (h *Handlers) deleteWebhookResources(
 	// be removed by hand; deleted history cannot be recovered.
 	err := h.commitWebhookDeletion(&webhook)
 	if err != nil {
-		h.serverError(w, r, "failed to delete webhook", err)
+		h.serverError(w, "failed to delete webhook", err)
 
 		return
 	}
@@ -655,7 +666,7 @@ func (h *Handlers) deleteWebhookResources(
 		// redirecting as though everything succeeded: the file
 		// needs removing by hand, and the logged error names it.
 		h.serverError(
-			w, r, "failed to delete webhook event database", err,
+			w, "failed to delete webhook event database", err,
 		)
 
 		return
@@ -799,7 +810,7 @@ func (h *Handlers) ownedWebhook(
 		"id = ? AND user_id = ?", sourceID, userID,
 	).First(&webhook).Error
 	if err != nil {
-		h.renderError(w, r, http.StatusNotFound)
+		http.NotFound(w, r)
 
 		return database.Webhook{}, false
 	}
@@ -821,7 +832,7 @@ func (h *Handlers) HandleSourceLogs() http.HandlerFunc {
 			// Without the map every delivery renders through a
 			// zero redactor, so failing the page is the only
 			// safe answer.
-			h.serverError(w, r, "failed to load targets", err)
+			h.serverError(w, "failed to load targets", err)
 
 			return
 		}
@@ -829,7 +840,7 @@ func (h *Handlers) HandleSourceLogs() http.HandlerFunc {
 		page := h.parsePage(r)
 
 		evts, total, ok := h.loadEventsWithDeliveries(
-			w, r, webhook, targets, page,
+			w, webhook, targets, page,
 		)
 		if !ok {
 			return
@@ -939,7 +950,6 @@ func (h *Handlers) parsePage(r *http.Request) int {
 // caller must then render nothing further.
 func (h *Handlers) loadEventsWithDeliveries(
 	w http.ResponseWriter,
-	r *http.Request,
 	webhook database.Webhook,
 	targetMap map[string]eventLogTarget,
 	page int,
@@ -953,7 +963,7 @@ func (h *Handlers) loadEventsWithDeliveries(
 	webhookDB, err := h.dbMgr.GetDB(webhook.ID)
 	if err != nil {
 		h.serverError(
-			w, r, "failed to get webhook database", err,
+			w, "failed to get webhook database", err,
 		)
 
 		return nil, 0, false
@@ -990,7 +1000,7 @@ func (h *Handlers) loadEventsWithDeliveries(
 	)
 	if err != nil {
 		h.serverError(
-			w, r, "failed to load delivery attempts", err,
+			w, "failed to load delivery attempts", err,
 		)
 
 		return nil, 0, false
@@ -999,7 +1009,7 @@ func (h *Handlers) loadEventsWithDeliveries(
 	resubmits, err := resubmitCounts(webhookDB, eventIDs)
 	if err != nil {
 		h.serverError(
-			w, r, "failed to count event resubmissions", err,
+			w, "failed to count event resubmissions", err,
 		)
 
 		return nil, 0, false
@@ -1222,7 +1232,7 @@ func (h *Handlers) HandleEntrypointCreate() http.HandlerFunc {
 			"id = ? AND user_id = ?", sourceID, userID,
 		).First(&webhook).Error
 		if err != nil {
-			h.renderError(w, r, http.StatusNotFound)
+			http.NotFound(w, r)
 
 			return
 		}
@@ -1231,7 +1241,9 @@ func (h *Handlers) HandleEntrypointCreate() http.HandlerFunc {
 		// middleware, which runs before CSRF parses the form.
 		err = r.ParseForm()
 		if err != nil {
-			h.renderError(w, r, http.StatusBadRequest)
+			http.Error(
+				w, "Bad request", http.StatusBadRequest,
+			)
 
 			return
 		}
@@ -1247,7 +1259,7 @@ func (h *Handlers) HandleEntrypointCreate() http.HandlerFunc {
 
 		err = h.db.DB().Create(entrypoint).Error
 		if err != nil {
-			h.serverError(w, r, "failed to create entrypoint", err)
+			h.serverError(w, "failed to create entrypoint", err)
 
 			return
 		}
@@ -1278,7 +1290,7 @@ func (h *Handlers) HandleTargetCreate() http.HandlerFunc {
 			"id = ? AND user_id = ?", sourceID, userID,
 		).First(&webhook).Error
 		if err != nil {
-			h.renderError(w, r, http.StatusNotFound)
+			http.NotFound(w, r)
 
 			return
 		}
@@ -1287,7 +1299,9 @@ func (h *Handlers) HandleTargetCreate() http.HandlerFunc {
 		// middleware, which runs before CSRF parses the form.
 		err = r.ParseForm()
 		if err != nil {
-			h.renderError(w, r, http.StatusBadRequest)
+			http.Error(
+				w, "Bad request", http.StatusBadRequest,
+			)
 
 			return
 		}
@@ -1358,7 +1372,7 @@ func (h *Handlers) processTargetCreate(
 
 	err = h.db.DB().Create(target).Error
 	if err != nil {
-		h.serverError(w, r, "failed to create target", err)
+		h.serverError(w, "failed to create target", err)
 
 		return
 	}
@@ -1452,7 +1466,7 @@ func (h *Handlers) buildTargetConfig(
 	case database.TargetTypeSlack:
 		return h.buildSlackTargetConfig(w, r, in.URL)
 	case database.TargetTypeDatabase:
-		return h.buildDatabaseTargetConfig(w, r, in.Expiry)
+		return h.buildDatabaseTargetConfig(w, in.Expiry)
 	case database.TargetTypeLog:
 		return "", nil
 	default:
@@ -1502,7 +1516,7 @@ func (h *Handlers) buildHTTPTargetConfig(
 		return "", err
 	}
 
-	return h.marshalTargetConfig(w, r, delivery.HTTPTargetConfig{
+	return marshalTargetConfig(w, delivery.HTTPTargetConfig{
 		URL:     in.URL,
 		Headers: headers,
 		Timeout: timeout,
@@ -1524,7 +1538,7 @@ func (h *Handlers) buildSlackTargetConfig(
 		return "", err
 	}
 
-	return h.marshalTargetConfig(w, r, delivery.SlackTargetConfig{
+	return marshalTargetConfig(w, delivery.SlackTargetConfig{
 		WebhookURL: targetURL,
 	})
 }
@@ -1578,14 +1592,16 @@ func (h *Handlers) validateTargetURL(
 
 // marshalTargetConfig serialises a target configuration for storage,
 // writing a 500 itself if it cannot.
-func (h *Handlers) marshalTargetConfig(
+func marshalTargetConfig(
 	w http.ResponseWriter,
-	r *http.Request,
 	cfg any,
 ) (string, error) {
 	configBytes, err := json.Marshal(cfg)
 	if err != nil {
-		h.serverError(w, r, "failed to encode target config", err)
+		http.Error(
+			w, "Internal server error",
+			http.StatusInternalServerError,
+		)
 
 		return "", err
 	}
@@ -1601,7 +1617,6 @@ func (h *Handlers) marshalTargetConfig(
 // expiry yields an empty config (the keep-forever default).
 func (h *Handlers) buildDatabaseTargetConfig(
 	w http.ResponseWriter,
-	r *http.Request,
 	expiry string,
 ) (string, error) {
 	expiry = strings.TrimSpace(expiry)
@@ -1620,8 +1635,8 @@ func (h *Handlers) buildDatabaseTargetConfig(
 		return "", err
 	}
 
-	return h.marshalTargetConfig(
+	return marshalTargetConfig(
-		w, r, map[string]any{"expiry": expiry},
+		w, map[string]any{"expiry": expiry},
 	)
 }
 
@@ -1675,7 +1690,7 @@ func (h *Handlers) deleteChildResource(
 			"id = ? AND user_id = ?", sourceID, userID,
 		).First(&webhook).Error
 		if err != nil {
-			h.renderError(w, r, http.StatusNotFound)
+			http.NotFound(w, r)
 
 			return
 		}
@@ -1685,7 +1700,11 @@ func (h *Handlers) deleteChildResource(
 			childID, webhook.ID,
 		).Delete(model)
 		if result.Error != nil {
-			h.serverError(w, r, errMsg, result.Error)
+			h.log.Error(errMsg, "error", result.Error)
+			http.Error(
+				w, "Internal server error",
+				http.StatusInternalServerError,
+			)
 
 			return
 		}
@@ -1775,14 +1794,18 @@ func (h *Handlers) toggleChildResource(
 			"id = ? AND user_id = ?", sourceID, userID,
 		).First(&webhook).Error
 		if err != nil {
-			h.renderError(w, r, http.StatusNotFound)
+			http.NotFound(w, r)
 
 			return
 		}
 
 		err = toggleFn(webhook.ID, childID)
 		if err != nil {
-			h.serverError(w, r, errMsg, err)
+			h.log.Error(errMsg, "error", err)
+			http.Error(
+				w, "Internal server error",
+				http.StatusInternalServerError,
+			)
 
 			return
 		}

internal/handlers/target_edit.go

@@ -88,7 +88,9 @@ func (h *Handlers) HandleTargetEditSubmit() http.HandlerFunc {
 		// middleware, which runs before CSRF parses the form.
 		err := r.ParseForm()
 		if err != nil {
-			h.renderError(w, r, http.StatusBadRequest)
+			http.Error(
+				w, "Bad request", http.StatusBadRequest,
+			)
 
 			return
 		}
@@ -155,7 +157,7 @@ func (h *Handlers) applyTargetEdit(
 
 	err = h.db.DB().Save(target).Error
 	if err != nil {
-		h.serverError(w, r, "failed to update target", err)
+		h.serverError(w, "failed to update target", err)
 
 		return
 	}
@@ -218,7 +220,7 @@ func (h *Handlers) ownedTarget(
 		chi.URLParam(r, "targetID"), webhook.ID,
 	).First(&target).Error
 	if err != nil {
-		h.renderError(w, r, http.StatusNotFound)
+		http.NotFound(w, r)
 
 		return database.Webhook{}, nil, false
 	}

internal/handlers/webhook.go

@@ -88,14 +88,14 @@ func (h *Handlers) processWebhookRequest(
 
 	headersJSON, err := json.Marshal(r.Header)
 	if err != nil {
-		h.receiverError(w, "failed to serialize headers", err)
+		h.serverError(w, "failed to serialize headers", err)
 
 		return
 	}
 
 	targets, err := h.loadActiveTargets(entrypoint.WebhookID)
 	if err != nil {
-		h.receiverError(w, "failed to query targets", err)
+		h.serverError(w, "failed to query targets", err)
 
 		return
 	}
@@ -196,7 +196,7 @@ func (h *Handlers) createAndDeliverEvent(
 		targets,
 	)
 	if err != nil {
-		h.receiverError(w, "failed to store webhook event", err)
+		h.serverError(w, "failed to store webhook event", err)
 
 		return
 	}
@@ -204,19 +204,6 @@ func (h *Handlers) createAndDeliverEvent(
 	h.finishWebhookResponse(w, event, entrypoint, tasks)
 }
 
-// receiverError logs an error and answers the sender with a plain-text
-// 500. The receiver's answers are for programs, so it never sends the
-// error page the web UI uses.
-func (h *Handlers) receiverError(
-	w http.ResponseWriter, msg string, err error,
-) {
-	h.log.Error(msg, "error", err)
-	http.Error(
-		w, "Internal server error",
-		http.StatusInternalServerError,
-	)
-}
-
 // eventSource carries the fields a new event is built from. The
 // receiver fills it from the live request; the resubmit handler fills
 // it from a stored event. Both then go through createAndFanOut, so an
@@ -266,11 +253,12 @@ func requestEventSource(
 	}
 }
 
-// createAndFanOut writes the event and one pending delivery per target
+// createAndFanOut writes the event and one pending delivery per target,
-// in a single transaction, then hands the tasks to the delivery
+// and adds them to the webhook's running totals, in a single
-// engine. It is the only path by which an event and its deliveries are
+// transaction, then hands the tasks to the delivery engine. It is the
-// created, so a resubmitted event is retried, SSRF-guarded and
+// only path by which an event and its deliveries are created, so a
-// circuit-broken exactly as a received one is.
+// resubmitted event is retried, SSRF-guarded and circuit-broken
+// exactly as a received one is.
 //
 // The tasks are returned as well as queued, so a caller can report how
 // many targets the event went to.
@@ -310,6 +298,15 @@ func (h *Handlers) createAndFanOut(
 		return nil, nil, err
 	}
 
+	err = database.AddEventTotals(tx, database.EventTotals{
+		Events: 1, LastEventAt: &event.CreatedAt,
+	})
+	if err != nil {
+		tx.Rollback()
+
+		return nil, nil, err
+	}
+
 	err = tx.Commit().Error
 	if err != nil {
 		return nil, nil, fmt.Errorf(
@@ -368,8 +365,9 @@ func (h *Handlers) finishWebhookResponse(
 }
 
 // buildDeliveryTasks creates one pending delivery per target in the
-// transaction and returns the tasks for the delivery engine. The
+// transaction, adds each to its target's totals, and returns the tasks
-// caller owns the transaction and rolls it back on error.
+// for the delivery engine. The caller owns the transaction and rolls
+// it back on error.
 func buildDeliveryTasks(
 	tx *gorm.DB,
 	event *database.Event,
@@ -393,6 +391,13 @@ func buildDeliveryTasks(
 			)
 		}
 
+		err = database.AddTargetTotals(tx, database.TargetTotals{
+			TargetID: targets[i].ID, Deliveries: 1,
+		})
+		if err != nil {
+			return nil, err
+		}
+
 		tasks = append(tasks, delivery.Task{
 			DeliveryID:   dlv.ID,
 			EventID:      event.ID,

internal/handlers/webhook_stats.go

@@ -0,0 +1,259 @@
+package handlers
+
+import (
+	"fmt"
+	"time"
+
+	"gorm.io/gorm"
+	"sneak.berlin/go/webhooker/internal/database"
+)
+
+// The spans of the two recent windows the statistics pane reports on:
+// the last 10 minutes and the last 24 hours.
+const (
+	shortWindow = 10 * time.Minute
+	longWindow  = 24 * time.Hour
+)
+
+// percent turns a fraction into a percentage.
+const percent = 100
+
+// WebhookStats holds the figures in the statistics pane at the top of
+// the webhook page.
+type WebhookStats struct {
+	Entrypoints       int
+	ActiveEntrypoints int
+	Targets           int
+	ActiveTargets     int
+
+	// Lifetime counts every event, delivery and failure the webhook
+	// has had, and WithinRetention those still stored.
+	Lifetime        Counts
+	WithinRetention Counts
+
+	// InProgress counts the deliveries still pending or retrying.
+	InProgress int64
+
+	// LastEventAt is when the newest event arrived, or nil when none
+	// has. Retention does not change it.
+	LastEventAt *time.Time
+
+	Last10Minutes RecentWindow
+	Last24Hours   RecentWindow
+}
+
+// Counts holds a number of events, of deliveries and of failed
+// deliveries.
+type Counts struct {
+	Events     int64
+	Deliveries int64
+	Failures   int64
+}
+
+// RecentWindow holds what happened in one recent window: the events
+// received in it, and the deliveries that became delivered or failed in
+// it.
+type RecentWindow struct {
+	Events    int64
+	Delivered int64
+	Failed    int64
+}
+
+// TargetFinished is how many of one target's deliveries became
+// delivered, and how many failed, in a recent window.
+type TargetFinished struct {
+	TargetID  string
+	Delivered int64
+	Failed    int64
+}
+
+// FailurePercent is the share of the deliveries finished in the window
+// that failed, or a dash when none finished. Deliveries still pending
+// or retrying are not counted either way.
+func (w RecentWindow) FailurePercent() string {
+	finished := w.Delivered + w.Failed
+	if finished == 0 {
+		return "—"
+	}
+
+	return fmt.Sprintf(
+		"%.1f%%", percent*float64(w.Failed)/float64(finished),
+	)
+}
+
+// loadWebhookStats gathers the figures for the statistics pane from the
+// webhook's entrypoints and targets, as the page has already loaded
+// them, and from its event database. It returns nil, and logs why, when
+// the event database cannot be read.
+func (h *Handlers) loadWebhookStats(
+	webhookID string,
+	entrypoints []database.Entrypoint,
+	targets []database.Target,
+) *WebhookStats {
+	stats := &WebhookStats{
+		Entrypoints: len(entrypoints),
+		Targets:     len(targets),
+	}
+
+	for i := range entrypoints {
+		if entrypoints[i].Active {
+			stats.ActiveEntrypoints++
+		}
+	}
+
+	for i := range targets {
+		if targets[i].Active {
+			stats.ActiveTargets++
+		}
+	}
+
+	// Opening an event database that does not exist would create it,
+	// and it would hold nothing to count.
+	if !h.dbMgr.DBExists(webhookID) {
+		return stats
+	}
+
+	webhookDB, err := h.dbMgr.GetDB(webhookID)
+	if err == nil {
+		err = readEventStats(webhookDB, time.Now(), stats)
+	}
+
+	if err != nil {
+		h.log.Error(
+			"failed to read webhook statistics",
+			"webhook_id", webhookID,
+			"error", err,
+		)
+
+		return nil
+	}
+
+	return stats
+}
+
+// readEventStats fills in the figures that come from the webhook's
+// event database. None of them reads every stored row: the totals are
+// one row for the events and one per target for the deliveries, and
+// every other figure is read from an index, over only the rows it
+// counts.
+func readEventStats(
+	db *gorm.DB, now time.Time, stats *WebhookStats,
+) error {
+	err := readTotals(db, stats)
+	if err != nil {
+		return err
+	}
+
+	err = db.Model(&database.Delivery{}).
+		Where("status IN ?", []database.DeliveryStatus{
+			database.DeliveryStatusPending,
+			database.DeliveryStatusRetrying,
+		}).
+		Count(&stats.InProgress).Error
+	if err != nil {
+		return fmt.Errorf("counting deliveries in progress: %w", err)
+	}
+
+	stats.Last10Minutes, err = readRecentWindow(
+		db, now.Add(-shortWindow),
+	)
+	if err != nil {
+		return err
+	}
+
+	stats.Last24Hours, err = readRecentWindow(
+		db, now.Add(-longWindow),
+	)
+
+	return err
+}
+
+// readTotals fills in the lifetime and within-retention figures, and
+// when the last event arrived, from the running totals: the events'
+// row, and the targets' rows summed.
+func readTotals(db *gorm.DB, stats *WebhookStats) error {
+	var events database.EventTotals
+
+	err := db.Take(&events).Error
+	if err != nil {
+		return fmt.Errorf("reading event totals: %w", err)
+	}
+
+	var targets []database.TargetTotals
+
+	err = db.Find(&targets).Error
+	if err != nil {
+		return fmt.Errorf("reading target totals: %w", err)
+	}
+
+	stats.Lifetime.Events = events.Events
+	stats.WithinRetention.Events = events.Events - events.EventsRemoved
+	stats.LastEventAt = events.LastEventAt
+
+	for _, t := range targets {
+		stats.Lifetime.Deliveries += t.Deliveries
+		stats.Lifetime.Failures += t.Failed
+		stats.WithinRetention.Deliveries += t.Deliveries - t.DeliveriesRemoved
+		stats.WithinRetention.Failures += t.Failed - t.FailedRemoved
+	}
+
+	return nil
+}
+
+// readRecentWindow counts the events received, and the deliveries that
+// became delivered or failed, since the given time.
+func readRecentWindow(
+	db *gorm.DB, since time.Time,
+) (RecentWindow, error) {
+	var w RecentWindow
+
+	err := db.Model(&database.Event{}).
+		Where("created_at >= ?", since).
+		Count(&w.Events).Error
+	if err != nil {
+		return w, fmt.Errorf("counting recent events: %w", err)
+	}
+
+	byTarget, err := finishedByTarget(db, since)
+	if err != nil {
+		return w, err
+	}
+
+	for _, f := range byTarget {
+		w.Delivered += f.Delivered
+		w.Failed += f.Failed
+	}
+
+	return w, nil
+}
+
+// finishedByTarget counts, for each target, the deliveries that became
+// delivered and those that failed since the given time, in one query
+// over just that window of the deliveries' status index. A target with
+// neither is left out.
+func finishedByTarget(
+	db *gorm.DB, since time.Time,
+) ([]TargetFinished, error) {
+	var byTarget []TargetFinished
+
+	err := db.Model(&database.Delivery{}).
+		Select("target_id, "+
+			"count(CASE WHEN status = ? THEN 1 END) AS delivered, "+
+			"count(CASE WHEN status = ? THEN 1 END) AS failed",
+			database.DeliveryStatusDelivered,
+			database.DeliveryStatusFailed).
+		Where("status IN ? AND finished_at >= ?",
+			[]database.DeliveryStatus{
+				database.DeliveryStatusDelivered,
+				database.DeliveryStatusFailed,
+			}, since).
+		Group("target_id").
+		Find(&byTarget).Error
+	if err != nil {
+		return nil, fmt.Errorf(
+			"counting deliveries finished by target: %w", err,
+		)
+	}
+
+	return byTarget, nil
+}

internal/handlers/webhook_stats_test.go

@@ -0,0 +1,564 @@
+package handlers_test
+
+import (
+	"net/http"
+	"regexp"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/fx/fxtest"
+	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
+	"sneak.berlin/go/webhooker/internal/config"
+	"sneak.berlin/go/webhooker/internal/database"
+	"sneak.berlin/go/webhooker/internal/handlers"
+	"sneak.berlin/go/webhooker/internal/logger"
+	"sneak.berlin/go/webhooker/internal/session"
+)
+
+// statsEntrypoint adds an entrypoint to a webhook and returns its path.
+func statsEntrypoint(
+	t *testing.T, db *database.Database, webhookID string, active bool,
+) string {
+	t.Helper()
+
+	ep := &database.Entrypoint{
+		WebhookID: webhookID,
+		Path:      uuid.New().String(),
+	}
+
+	require.NoError(t, db.DB().Omit(clause.Associations).Create(ep).Error)
+	require.NoError(t, db.DB().Model(ep).Update("active", active).Error)
+
+	return ep.Path
+}
+
+// statsDelivery returns an event's delivery to a target.
+func statsDelivery(
+	t *testing.T, webhookDB *gorm.DB, eventID, targetID string,
+) database.Delivery {
+	t.Helper()
+
+	var d database.Delivery
+
+	require.NoError(t, webhookDB.Where(
+		"event_id = ? AND target_id = ?", eventID, targetID,
+	).First(&d).Error)
+
+	return d
+}
+
+// statsFinish settles a delivery as the delivery engine does: its
+// final status and the time it finished, and one more on its target's
+// delivered or failed total, in one transaction.
+func statsFinish(
+	t *testing.T,
+	webhookDB *gorm.DB,
+	d database.Delivery,
+	status database.DeliveryStatus,
+	at time.Time,
+) {
+	t.Helper()
+
+	add := database.TargetTotals{TargetID: d.TargetID, Delivered: 1}
+	if status == database.DeliveryStatusFailed {
+		add = database.TargetTotals{TargetID: d.TargetID, Failed: 1}
+	}
+
+	require.NoError(t, webhookDB.Transaction(func(tx *gorm.DB) error {
+		err := tx.Model(&database.Delivery{}).
+			Where("id = ?", d.ID).
+			Updates(map[string]any{"status": status, "finished_at": at}).
+			Error
+		if err != nil {
+			return err
+		}
+
+		return database.AddTargetTotals(tx, add)
+	}))
+}
+
+// statsAge moves an event's arrival back to the given time.
+func statsAge(
+	t *testing.T, webhookDB *gorm.DB, eventID string, at time.Time,
+) {
+	t.Helper()
+
+	require.NoError(t, webhookDB.Model(&database.Event{}).
+		Where("id = ?", eventID).
+		Update("created_at", at).Error)
+}
+
+// statsTargetTotals reads a webhook database's target totals, keyed by
+// target.
+func statsTargetTotals(
+	t *testing.T, webhookDB *gorm.DB,
+) map[string]database.TargetTotals {
+	t.Helper()
+
+	var rows []database.TargetTotals
+
+	require.NoError(t, webhookDB.Find(&rows).Error)
+
+	byTarget := make(map[string]database.TargetTotals, len(rows))
+	for _, row := range rows {
+		byTarget[row.TargetID] = row
+	}
+
+	return byTarget
+}
+
+// statsHistory is the webhook seedStatsHistory builds: its event
+// database, its newest event, and its two active targets.
+type statsHistory struct {
+	webhook       *database.Webhook
+	webhookDB     *gorm.DB
+	newest        database.Event
+	first, second string
+}
+
+// seedStatsHistory builds the webhook the statistics test checks: 14
+// days of retention, eleven entrypoints (one inactive) and five targets
+// (three inactive). Nine events arrive through the receiver, and so
+// each has a delivery to the two active targets. The oldest event is
+// past retention, the next 30 hours old, the next six hours old, the
+// other six just in. Five deliveries are settled as the delivery engine
+// would, the rest left pending, and a replay adds a pending delivery to
+// the oldest event. Once retention has removed the oldest event, every
+// figure in the pane differs from every other.
+func seedStatsHistory(
+	t *testing.T,
+	h *handlers.Handlers,
+	sess *session.Session,
+	db *database.Database,
+	dbMgr *database.WebhookDBManager,
+) statsHistory {
+	t.Helper()
+
+	wh := &database.Webhook{
+		UserID: deleteTestUserID, Name: "stats", RetentionDays: 14,
+	}
+	require.NoError(t, db.DB().Omit(clause.Associations).Create(wh).Error)
+
+	path := statsEntrypoint(t, db, wh.ID, true)
+	for range 9 {
+		statsEntrypoint(t, db, wh.ID, true)
+	}
+
+	statsEntrypoint(t, db, wh.ID, false)
+
+	first := seedConfiguredTarget(
+		t, db, wh.ID, database.TargetTypeHTTP,
+		`{"url":"`+replayTargetURL+`"}`,
+	)
+	second := seedTarget(t, db, wh.ID, database.TargetTypeLog)
+
+	for range 3 {
+		inactive := seedTarget(t, db, wh.ID, database.TargetTypeLog)
+		require.NoError(t, db.DB().Model(inactive).
+			Update("active", false).Error)
+	}
+
+	router := receiverRouter(h)
+
+	for range 9 {
+		require.Equal(t, http.StatusOK, postReceiver(t, router, path))
+	}
+
+	webhookDB, err := dbMgr.GetDB(wh.ID)
+	require.NoError(t, err)
+
+	events := listEvents(t, webhookDB)
+	require.Len(t, events, 9)
+
+	oldest, yesterday, middle, newest := events[0], events[1], events[2], events[8]
+	now := time.Now()
+
+	statsAge(t, webhookDB, oldest.ID, now.Add(-15*24*time.Hour))
+	statsAge(t, webhookDB, yesterday.ID, now.Add(-30*time.Hour))
+	statsAge(t, webhookDB, middle.ID, now.Add(-6*time.Hour))
+
+	oldestFailure := statsDelivery(t, webhookDB, oldest.ID, first.ID)
+	statsFinish(t, webhookDB, oldestFailure,
+		database.DeliveryStatusFailed, now.Add(-14*24*time.Hour))
+	statsFinish(t, webhookDB,
+		statsDelivery(t, webhookDB, yesterday.ID, first.ID),
+		database.DeliveryStatusFailed, now.Add(-29*time.Hour))
+	statsFinish(t, webhookDB,
+		statsDelivery(t, webhookDB, yesterday.ID, second.ID),
+		database.DeliveryStatusFailed, now.Add(-29*time.Hour))
+	statsFinish(t, webhookDB,
+		statsDelivery(t, webhookDB, middle.ID, second.ID),
+		database.DeliveryStatusFailed, now.Add(-5*time.Hour))
+	statsFinish(t, webhookDB,
+		statsDelivery(t, webhookDB, newest.ID, first.ID),
+		database.DeliveryStatusDelivered, now.Add(-2*time.Minute))
+
+	require.Equal(t, http.StatusSeeOther,
+		postReplay(t, h, sess, wh.ID, oldestFailure.ID).Code)
+
+	return statsHistory{
+		webhook:   wh,
+		webhookDB: webhookDB,
+		newest:    newest,
+		first:     first.ID,
+		second:    second.ID,
+	}
+}
+
+// statsPrune runs the real retention reaper until it has removed one
+// event from the webhook's database, then stops it.
+func statsPrune(
+	t *testing.T,
+	db *database.Database,
+	dbMgr *database.WebhookDBManager,
+	log *logger.Logger,
+	webhookDB *gorm.DB,
+) {
+	t.Helper()
+
+	lc := fxtest.NewLifecycle(t)
+	database.NewRetentionReaper(lc, database.RetentionReaperParams{
+		Config: &config.Config{
+			RetentionSweepInterval: 10 * time.Millisecond,
+		},
+		Database:  db,
+		DBManager: dbMgr,
+		Logger:    log,
+	})
+
+	lc.RequireStart()
+
+	require.Eventually(t, func() bool {
+		var totals database.EventTotals
+
+		err := webhookDB.Take(&totals).Error
+
+		return err == nil && totals.EventsRemoved == 1
+	}, 10*time.Second, 10*time.Millisecond)
+
+	lc.RequireStop()
+}
+
+// statsPane returns the text of the statistics pane in a rendered
+// webhook page, everything from its heading to the next heading on the
+// page, with the markup taken out and each run of space made one
+// space. A table then reads header by header and row by row, each
+// row's label followed by its figures in column order.
+func statsPane(t *testing.T, page string) string {
+	t.Helper()
+
+	_, pane, found := strings.Cut(page, ">Statistics</h2>")
+	require.True(t, found, "the page has no statistics pane")
+
+	pane, _, _ = strings.Cut(pane, "<h2")
+	pane = regexp.MustCompile(`<[^>]*>`).ReplaceAllString(pane, " ")
+
+	return strings.Join(strings.Fields(pane), " ")
+}
+
+// assertStatsTargets checks, for the history seedStatsHistory builds,
+// each target's totals and its deliveries finished in the last 24
+// hours. The first target has nine deliveries and the replay, the
+// second nine; the inactive targets have none and so no row.
+func assertStatsTargets(t *testing.T, hist statsHistory) {
+	t.Helper()
+
+	first, second := hist.first, hist.second
+
+	assert.Equal(t, map[string]database.TargetTotals{
+		first:  {TargetID: first, Deliveries: 10, Delivered: 1, Failed: 2},
+		second: {TargetID: second, Deliveries: 9, Failed: 2},
+	}, statsTargetTotals(t, hist.webhookDB))
+
+	lastDay, err := handlers.FinishedByTargetForTest(
+		hist.webhookDB, time.Now().Add(-24*time.Hour),
+	)
+	require.NoError(t, err)
+	assert.ElementsMatch(t, []handlers.TargetFinished{
+		{TargetID: first, Delivered: 1},
+		{TargetID: second, Failed: 1},
+	}, lastDay)
+}
+
+// assertStatsPaneAfterPrune checks the rendered statistics pane for the
+// history seedStatsHistory builds, once retention has removed the
+// oldest event: each figure after its label, in its column.
+func assertStatsPaneAfterPrune(
+	t *testing.T,
+	h *handlers.Handlers,
+	sess *session.Session,
+	hist statsHistory,
+) {
+	t.Helper()
+
+	pane := statsPane(t, renderSourceDetailPage(t, h, sess, hist.webhook.ID))
+	lastEvent := hist.newest.CreatedAt.UTC().Format("2006-01-02 15:04:05 UTC")
+
+	assert.Contains(t, pane, "Entrypoints 11 (10 active) "+
+		"Targets 5 (2 active) "+
+		"Deliveries in progress 12 "+
+		"Last event "+lastEvent+" "+
+		"Retention 14 days")
+	assert.Contains(t, pane, "Lifetime Within retention "+
+		"Events 9 8 "+
+		"Deliveries 19 16 "+
+		"Failures 4 3")
+	assert.Contains(t, pane, "Last 10 minutes Last 24 hours "+
+		"Events 6 7 "+
+		"Failures 0 1 "+
+		"Failure percentage 0.0% 50.0%")
+}
+
+// TestWebhookStats_EveryFigureAcrossRetentionPrune checks every figure
+// the statistics pane shows for the history seedStatsHistory builds,
+// and each target's totals and recent figures, before and after the
+// real retention reaper removes the oldest event.
+func TestWebhookStats_EveryFigureAcrossRetentionPrune(t *testing.T) {
+	t.Parallel()
+
+	var (
+		h     *handlers.Handlers
+		sess  *session.Session
+		db    *database.Database
+		dbMgr *database.WebhookDBManager
+		log   *logger.Logger
+	)
+
+	app := newTestApp(t, &h, &sess, &db, &dbMgr, &log)
+	app.RequireStart()
+
+	t.Cleanup(app.RequireStop)
+
+	hist := seedStatsHistory(t, h, sess, db, dbMgr)
+	first, second := hist.first, hist.second
+
+	stats := h.WebhookStatsForTest(hist.webhook.ID)
+	require.NotNil(t, stats)
+
+	assert.Equal(t, 11, stats.Entrypoints)
+	assert.Equal(t, 10, stats.ActiveEntrypoints)
+	assert.Equal(t, 5, stats.Targets)
+	assert.Equal(t, 2, stats.ActiveTargets)
+	assert.Equal(t, handlers.Counts{Events: 9, Deliveries: 19, Failures: 4},
+		stats.Lifetime)
+	assert.Equal(t, stats.Lifetime, stats.WithinRetention)
+	assert.Equal(t, int64(14), stats.InProgress)
+	require.NotNil(t, stats.LastEventAt)
+	assert.True(t, hist.newest.CreatedAt.Equal(*stats.LastEventAt))
+	assert.Equal(t, handlers.RecentWindow{Events: 6, Delivered: 1},
+		stats.Last10Minutes)
+	assert.Equal(t, handlers.RecentWindow{
+		Events: 7, Delivered: 1, Failed: 1,
+	}, stats.Last24Hours)
+	assert.Equal(t, "0.0%", stats.Last10Minutes.FailurePercent())
+	assert.Equal(t, "50.0%", stats.Last24Hours.FailurePercent())
+
+	assertStatsTargets(t, hist)
+
+	// Retention removes the oldest event with its three deliveries:
+	// the first target's failed one and the pending replay, and the
+	// second target's pending one.
+	statsPrune(t, db, dbMgr, log, hist.webhookDB)
+
+	after := h.WebhookStatsForTest(hist.webhook.ID)
+	require.NotNil(t, after)
+
+	assert.Equal(t, stats.Lifetime, after.Lifetime)
+	assert.Equal(t, handlers.Counts{Events: 8, Deliveries: 16, Failures: 3},
+		after.WithinRetention)
+	assert.Equal(t, int64(12), after.InProgress)
+	assert.Equal(t, stats.LastEventAt, after.LastEventAt)
+	assert.Equal(t, stats.Last10Minutes, after.Last10Minutes)
+	assert.Equal(t, stats.Last24Hours, after.Last24Hours)
+
+	assert.Equal(t, map[string]database.TargetTotals{
+		first: {
+			TargetID: first, Deliveries: 10, Delivered: 1, Failed: 2,
+			DeliveriesRemoved: 2, FailedRemoved: 1,
+		},
+		second: {
+			TargetID: second, Deliveries: 9, Failed: 2,
+			DeliveriesRemoved: 1,
+		},
+	}, statsTargetTotals(t, hist.webhookDB))
+
+	assertStatsPaneAfterPrune(t, h, sess, hist)
+}
+
+// TestWebhookStats_LastEventSurvivesPruningEveryEvent checks that once
+// retention has removed every event, the pane still shows when the last
+// one arrived rather than "none".
+func TestWebhookStats_LastEventSurvivesPruningEveryEvent(t *testing.T) {
+	t.Parallel()
+
+	var (
+		h     *handlers.Handlers
+		sess  *session.Session
+		db    *database.Database
+		dbMgr *database.WebhookDBManager
+		log   *logger.Logger
+	)
+
+	app := newTestApp(t, &h, &sess, &db, &dbMgr, &log)
+	app.RequireStart()
+
+	t.Cleanup(app.RequireStop)
+
+	wh := &database.Webhook{
+		UserID: deleteTestUserID, Name: "pruned", RetentionDays: 1,
+	}
+	require.NoError(t, db.DB().Omit(clause.Associations).Create(wh).Error)
+
+	path := statsEntrypoint(t, db, wh.ID, true)
+	require.Equal(t, http.StatusOK,
+		postReceiver(t, receiverRouter(h), path))
+
+	webhookDB, err := dbMgr.GetDB(wh.ID)
+	require.NoError(t, err)
+
+	events := listEvents(t, webhookDB)
+	require.Len(t, events, 1)
+
+	arrived := events[0].CreatedAt
+
+	statsAge(t, webhookDB, events[0].ID, time.Now().Add(-50*time.Hour))
+	statsPrune(t, db, dbMgr, log, webhookDB)
+	require.Empty(t, listEvents(t, webhookDB))
+
+	stats := h.WebhookStatsForTest(wh.ID)
+	require.NotNil(t, stats)
+	require.NotNil(t, stats.LastEventAt)
+	assert.True(t, arrived.Equal(*stats.LastEventAt))
+
+	pane := statsPane(t, renderSourceDetailPage(t, h, sess, wh.ID))
+	assert.Contains(t, pane,
+		"Last event "+arrived.UTC().Format("2006-01-02 15:04:05 UTC"))
+}
+
+// TestWebhookStats_LastEventInUTC checks that the pane shows when the
+// last event arrived in UTC, as the event list does, when the time was
+// stored in another zone, as it is on a host whose local time is not
+// UTC.
+func TestWebhookStats_LastEventInUTC(t *testing.T) {
+	t.Parallel()
+
+	var (
+		h     *handlers.Handlers
+		sess  *session.Session
+		db    *database.Database
+		dbMgr *database.WebhookDBManager
+	)
+
+	app := newTestApp(t, &h, &sess, &db, &dbMgr)
+	app.RequireStart()
+
+	t.Cleanup(app.RequireStop)
+
+	wh := seedWebhook(t, db)
+
+	webhookDB, err := dbMgr.GetDB(wh.ID)
+	require.NoError(t, err)
+
+	arrived := time.Date(2026, time.March, 4, 22, 30, 0, 0,
+		time.FixedZone("EST", -5*60*60))
+	require.NoError(t, database.AddEventTotals(webhookDB,
+		database.EventTotals{Events: 1, LastEventAt: &arrived}))
+
+	pane := statsPane(t, renderSourceDetailPage(t, h, sess, wh.ID))
+	assert.Contains(t, pane, "Last event 2026-03-05 03:30:00 UTC")
+}
+
+// TestWebhookStats_PaneShowsRetentionPeriod checks that the statistics
+// pane itself, not only the line at the foot of the page, shows the
+// webhook's retention period, for a finite one and for forever.
+func TestWebhookStats_PaneShowsRetentionPeriod(t *testing.T) {
+	t.Parallel()
+
+	var (
+		h    *handlers.Handlers
+		sess *session.Session
+		db   *database.Database
+	)
+
+	app := newTestApp(t, &h, &sess, &db)
+	app.RequireStart()
+
+	t.Cleanup(app.RequireStop)
+
+	tests := []struct {
+		retentionDays int
+		want          string
+	}{
+		{30, "30 days"},
+		{database.RetentionForeverDays, "forever"},
+	}
+
+	for _, tt := range tests {
+		wh := &database.Webhook{
+			UserID:        deleteTestUserID,
+			Name:          "retention",
+			RetentionDays: tt.retentionDays,
+		}
+		require.NoError(t,
+			db.DB().Omit(clause.Associations).Create(wh).Error)
+
+		pane := statsPane(t, renderSourceDetailPage(t, h, sess, wh.ID))
+		assert.Contains(t, pane, "Retention "+tt.want)
+	}
+}
+
+// TestWebhookStats_WebhookWithNoEvents covers a webhook whose event
+// database has never been opened: every count is zero, the
+// percentages are a dash, and showing the page does not create the
+// database.
+func TestWebhookStats_WebhookWithNoEvents(t *testing.T) {
+	t.Parallel()
+
+	var (
+		h     *handlers.Handlers
+		sess  *session.Session
+		db    *database.Database
+		dbMgr *database.WebhookDBManager
+	)
+
+	app := newTestApp(t, &h, &sess, &db, &dbMgr)
+	app.RequireStart()
+
+	t.Cleanup(app.RequireStop)
+
+	wh := seedWebhook(t, db)
+
+	assert.Equal(t, &handlers.WebhookStats{}, h.WebhookStatsForTest(wh.ID))
+	assert.Equal(t, "—", handlers.RecentWindow{}.FailurePercent())
+
+	pane := statsPane(t, renderSourceDetailPage(t, h, sess, wh.ID))
+	assert.Contains(t, pane, "Last event none")
+	assert.Contains(t, pane, "Failure percentage — —")
+	assert.False(t, dbMgr.DBExists(wh.ID))
+}
+
+// TestRecentWindow_FailurePercent pins the percentage: failed
+// deliveries out of all that finished in the window.
+func TestRecentWindow_FailurePercent(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		window handlers.RecentWindow
+		want   string
+	}{
+		{handlers.RecentWindow{}, "—"},
+		{handlers.RecentWindow{Events: 4}, "—"},
+		{handlers.RecentWindow{Delivered: 3, Failed: 1}, "25.0%"},
+		{handlers.RecentWindow{Failed: 2}, "100.0%"},
+		{handlers.RecentWindow{Delivered: 2}, "0.0%"},
+	}
+
+	for _, tt := range tests {
+		assert.Equal(t, tt.want, tt.window.FailurePercent(), tt.window)
+	}
+}

internal/middleware/csrf.go

@@ -19,7 +19,7 @@ func CSRFToken(r *http.Request) string {
 // key to sign a CSRF cookie and validates a masked token submitted via
 // the "csrf_token" form field (or the "X-CSRF-Token" header) on
 // POST/PUT/PATCH/DELETE requests. Requests with an invalid or missing
-// token are logged and answered by forbidden, which must write the 403.
+// token receive a 403 Forbidden response.
 //
 // The middleware detects the client-facing transport protocol
 // per-request via reqtls.IsTLS, the single TLS predicate the session
@@ -36,9 +36,7 @@ func CSRFToken(r *http.Request) string {
 // Two gorilla/csrf instances are maintained — one with Secure cookies
 // (for TLS) and one without (for plaintext HTTP) — because the
 // csrf.Secure option is set at creation time, not per-request.
-func (m *Middleware) CSRF(
+func (m *Middleware) CSRF() func(http.Handler) http.Handler {
-	forbidden http.Handler,
-) func(http.Handler) http.Handler {
 	csrfErrorHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		// CSRF is registered ahead of RequireAuth on every route
 		// group that uses it, so this WARN is reachable by an
@@ -59,7 +57,7 @@ func (m *Middleware) CSRF(
 			"remote_addr", r.RemoteAddr,
 			"reason", csrf.FailureReason(r),
 		)
-		forbidden.ServeHTTP(w, r)
+		http.Error(w, "Forbidden - invalid CSRF token", http.StatusForbidden)
 	})
 
 	key := m.session.GetKey()

internal/middleware/csrf_test.go

@@ -18,12 +18,6 @@ import (
 // csrfCookieName is the gorilla/csrf cookie name.
 const csrfCookieName = "_gorilla_csrf"
 
-// forbidden stands in for the error page the server hands CSRF to
-// answer a refused request with.
-func forbidden(w http.ResponseWriter, _ *http.Request) {
-	w.WriteHeader(http.StatusForbidden)
-}
-
 // csrfGetToken performs a GET request through the CSRF middleware
 // and returns the token and cookies.
 func csrfGetToken(
@@ -104,7 +98,7 @@ func TestCSRF_GETSetsToken(t *testing.T) {
 
 	var gotToken string
 
-	handler := m.CSRF(http.HandlerFunc(forbidden))(http.HandlerFunc(
+	handler := m.CSRF()(http.HandlerFunc(
 		func(_ http.ResponseWriter, r *http.Request) {
 			gotToken = middleware.CSRFToken(r)
 		},
@@ -126,7 +120,7 @@ func TestCSRF_POSTWithValidToken(t *testing.T) {
 	t.Parallel()
 
 	m, _ := testMiddleware(t, config.EnvironmentDev)
-	csrfMW := m.CSRF(http.HandlerFunc(forbidden))
+	csrfMW := m.CSRF()
 
 	getReq := httptest.NewRequestWithContext(
 		context.Background(),
@@ -158,7 +152,7 @@ func csrfPOSTWithoutTokenTest(
 	t.Helper()
 
 	m, _ := testMiddleware(t, env)
-	csrfMW := m.CSRF(http.HandlerFunc(forbidden))
+	csrfMW := m.CSRF()
 
 	// GET to establish the CSRF cookie
 	getHandler := csrfMW(http.HandlerFunc(
@@ -215,7 +209,7 @@ func TestCSRF_POSTWithInvalidToken(t *testing.T) {
 	t.Parallel()
 
 	m, _ := testMiddleware(t, config.EnvironmentDev)
-	csrfMW := m.CSRF(http.HandlerFunc(forbidden))
+	csrfMW := m.CSRF()
 
 	// GET to establish the CSRF cookie
 	getHandler := csrfMW(http.HandlerFunc(
@@ -271,7 +265,7 @@ func TestCSRF_GETDoesNotValidate(t *testing.T) {
 
 	var called bool
 
-	handler := m.CSRF(http.HandlerFunc(forbidden))(http.HandlerFunc(
+	handler := m.CSRF()(http.HandlerFunc(
 		func(_ http.ResponseWriter, _ *http.Request) {
 			called = true
 		},
@@ -334,7 +328,7 @@ func csrfTookStrictPath(
 	t.Helper()
 
 	m, _ := testMiddleware(t, env)
-	csrfMW := m.CSRF(http.HandlerFunc(forbidden))
+	csrfMW := m.CSRF()
 
 	newReq := func(method string) *http.Request {
 		r := httptest.NewRequestWithContext(
@@ -483,7 +477,7 @@ func TestCSRF_ProdMode_PlaintextHTTP_POSTWithValidToken(
 	t.Parallel()
 
 	m, _ := testMiddleware(t, config.EnvironmentProd)
-	csrfMW := m.CSRF(http.HandlerFunc(forbidden))
+	csrfMW := m.CSRF()
 
 	getReq := httptest.NewRequestWithContext(
 		context.Background(),
@@ -523,7 +517,7 @@ func TestCSRF_ProdMode_BehindProxy_POSTWithValidToken(
 	t.Parallel()
 
 	m, _ := testMiddleware(t, config.EnvironmentProd)
-	csrfMW := m.CSRF(http.HandlerFunc(forbidden))
+	csrfMW := m.CSRF()
 
 	getReq := httptest.NewRequestWithContext(
 		context.Background(),
@@ -568,7 +562,7 @@ func TestCSRF_ProdMode_DirectTLS_POSTWithValidToken(
 	t.Parallel()
 
 	m, _ := testMiddleware(t, config.EnvironmentProd)
-	csrfMW := m.CSRF(http.HandlerFunc(forbidden))
+	csrfMW := m.CSRF()
 
 	getReq := httptest.NewRequestWithContext(
 		context.Background(),

internal/middleware/logbound_test.go

@@ -260,9 +260,7 @@ func logSites() map[string]logSite {
 			) http.Handler {
 				t.Helper()
 
-				return m.CSRF(http.HandlerFunc(forbidden))(
+				return m.CSRF()(unreachable(t))
-					unreachable(t),
-				)
 			},
 			send:       postNoToken,
 			wantStatus: http.StatusForbidden,

internal/middleware/recoverer.go

@@ -109,8 +109,7 @@ func (w *recoverResponseWriter) Unwrap() http.ResponseWriter {
 
 // Recoverer returns middleware that turns a handler panic into one
 // structured ERROR record and a 500, rather than a dropped
-// connection. The 500 is page when page is not nil, and plain text
+// connection.
-// when it is nil or when page panics before writing anything.
 //
 // It replaces chi's middleware.Recoverer, which does neither on a
 // current Go release. chi v1.5.5's pretty-printer scans the stack for
@@ -137,13 +136,9 @@ func (w *recoverResponseWriter) Unwrap() http.ResponseWriter {
 //
 // Unlike http.Error on its own, it deletes any Set-Cookie the handler
 // set before panicking, because a request that failed must not hand
-// the client a credential. It touches no other header: when page
+// the client a credential; every other header is left to http.Error.
-// answers, every other header the handler set goes out with it, apart
-// from any page sets itself; otherwise they are left to http.Error.
 // See https://git.eeqj.de/sneak/webhooker/issues/193.
-func (s *Middleware) Recoverer(
+func (s *Middleware) Recoverer() func(http.Handler) http.Handler {
-	page http.Handler,
-) func(http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(
 			w http.ResponseWriter,
@@ -176,14 +171,6 @@ func (s *Middleware) Recoverer(
 
 				rw.Header().Del("Set-Cookie")
 
-				if page != nil {
-					s.servePage(rw, r, page)
-				}
-
-				if rw.committed {
-					return
-				}
-
 				http.Error(
 					rw,
 					http.StatusText(
@@ -198,27 +185,6 @@ func (s *Middleware) Recoverer(
 	}
 }
 
-// servePage answers with page. A panic in page itself is logged and
-// recovered here, so the Recoverer can still send its plain 500.
-func (s *Middleware) servePage(
-	w http.ResponseWriter,
-	r *http.Request,
-	page http.Handler,
-) {
-	defer func() {
-		rvr := recover()
-		if rvr != nil {
-			s.log.Error("error page panic",
-				"panic", logfield.Truncate(
-					fmt.Sprint(rvr), maxPanicValueBytes,
-				),
-			)
-		}
-	}()
-
-	page.ServeHTTP(w, r)
-}
-
 // logPanic writes the record. Every field it can grow is truncated to
 // a fixed budget, so MaxPanicLogLineBytes holds.
 //

internal/middleware/recoverer_test.go

@@ -76,7 +76,7 @@ func newRecovererProbe(
 	// Logging outside so the recovered 500 is the status it records.
 	router.Use(chimw.RequestID)
 	router.Use(m.Logging())
-	router.Use(m.Recoverer(nil))
+	router.Use(m.Recoverer())
 	router.Get("/probe", handler)
 
 	serverErrors := new(bytes.Buffer)
@@ -637,7 +637,7 @@ func TestRecovererKeepsResponseControllerWorking(t *testing.T) {
 
 	m, _ := capturingMiddleware(t)
 
-	handler := m.Recoverer(nil)(http.HandlerFunc(
+	handler := m.Recoverer()(http.HandlerFunc(
 		func(w http.ResponseWriter, _ *http.Request) {
 			_, _ = w.Write([]byte("chunk"))
 
@@ -672,59 +672,3 @@ func TestRecovererKeepsResponseControllerWorking(t *testing.T) {
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
 	assert.Equal(t, "chunk", string(body))
 }
-
-// TestRecovererAnswersWithThePage covers a recoverer given a page:
-// the panic is logged as before, and the 500 is that page.
-func TestRecovererAnswersWithThePage(t *testing.T) {
-	t.Parallel()
-
-	m, logs := capturingMiddleware(t)
-
-	page := http.HandlerFunc(
-		func(w http.ResponseWriter, _ *http.Request) {
-			w.WriteHeader(http.StatusInternalServerError)
-			_, _ = w.Write([]byte("the error page"))
-		},
-	)
-
-	w := httptest.NewRecorder()
-	m.Recoverer(page)(http.HandlerFunc(panicProbe)).ServeHTTP(
-		w, httptest.NewRequestWithContext(
-			t.Context(), http.MethodGet, "/", nil,
-		),
-	)
-
-	assert.Equal(t, http.StatusInternalServerError, w.Code)
-	assert.Equal(t, "the error page", w.Body.String())
-	assert.Contains(t, logs.String(), `"msg":"handler panic"`)
-	assert.Contains(t, logs.String(), panicMarker)
-}
-
-// TestRecovererFallsBackWhenThePagePanics covers a page that panics
-// before writing anything: both panics are logged, and the client
-// still gets the plain 500.
-func TestRecovererFallsBackWhenThePagePanics(t *testing.T) {
-	t.Parallel()
-
-	m, logs := capturingMiddleware(t)
-
-	const pagePanic = "QQERRORPAGEPANICQQ"
-
-	page := http.HandlerFunc(
-		func(http.ResponseWriter, *http.Request) {
-			panic(pagePanic)
-		},
-	)
-
-	w := httptest.NewRecorder()
-	m.Recoverer(page)(http.HandlerFunc(panicProbe)).ServeHTTP(
-		w, httptest.NewRequestWithContext(
-			t.Context(), http.MethodGet, "/", nil,
-		),
-	)
-
-	assert.Equal(t, http.StatusInternalServerError, w.Code)
-	assert.Equal(t, "Internal Server Error\n", w.Body.String())
-	assert.Contains(t, logs.String(), panicMarker)
-	assert.Contains(t, logs.String(), pagePanic)
-}

internal/resetpw/resetpw_test.go

@@ -140,7 +140,7 @@ func (n *noopEvictor) EvictWebhook(string) {}
 // and the database, exactly as internal/handlers builds them.
 //
 // One application per test function, not per case: every start that
-// finds no account seeds one at 64 MB of Argon2id, and this package's
+// finds no account seeds one with an Argon2id hash, and this package's
 // budget is not the place to spend that repeatedly.
 func newServerApp(
 	t *testing.T, dir string,

internal/server/error_page_test.go

@@ -1,220 +0,0 @@
-package server_test
-
-import (
-	"context"
-	"net/http"
-	"net/http/httptest"
-	"net/url"
-	"strconv"
-	"testing"
-
-	"github.com/getsentry/sentry-go"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-	"sneak.berlin/go/webhooker/internal/config"
-	"sneak.berlin/go/webhooker/internal/server"
-)
-
-// The link back the error page offers: to the webhook list for a
-// signed-in user, to sign-in for anyone else.
-const (
-	backToWebhooks = `<a href="/sources" class="btn-secondary">` +
-		`Back to webhooks</a>`
-	backToSignIn = `<a href="/pages/login" class="btn-primary">` +
-		`Sign in</a>`
-)
-
-// assertErrorPage checks that w is the error page for status, in the
-// normal layout, offering link.
-func assertErrorPage(
-	t *testing.T,
-	w *httptest.ResponseRecorder,
-	status int,
-	link string,
-) {
-	t.Helper()
-
-	body := w.Body.String()
-
-	assert.Equal(t, status, w.Code)
-	assert.Equal(
-		t, "text/html; charset=utf-8", w.Header().Get("Content-Type"),
-	)
-	assert.Equal(t, "no-store", w.Header().Get("Cache-Control"))
-	assert.Contains(t, body, `<nav class="app-bar"`)
-	assert.Contains(
-		t, body, strconv.Itoa(status)+" "+http.StatusText(status),
-	)
-	assert.Contains(t, body, link)
-}
-
-func TestErrorPage_DeletedWebhook(t *testing.T) {
-	t.Parallel()
-
-	env := newTestEnv(t)
-
-	userID, _ := env.seedUser(t, "owner", "somepassword")
-	cookies := env.authCookies(t, userID, "owner")
-
-	wh := env.seedWebhook(t, userID)
-	require.NoError(t, env.db.DB().Delete(wh).Error)
-
-	w := env.get("/source/"+wh.ID, cookies)
-
-	assertErrorPage(t, w, http.StatusNotFound, backToWebhooks)
-}
-
-func TestErrorPage_DeletedTarget(t *testing.T) {
-	t.Parallel()
-
-	env := newTestEnv(t)
-
-	userID, _ := env.seedUser(t, "owner", "somepassword")
-	cookies := env.authCookies(t, userID, "owner")
-
-	wh := env.seedWebhook(t, userID)
-	tgt := env.seedTarget(t, wh.ID)
-	require.NoError(t, env.db.DB().Delete(tgt).Error)
-
-	w := env.get(
-		"/source/"+wh.ID+"/targets/"+tgt.ID+"/edit", cookies,
-	)
-
-	assertErrorPage(t, w, http.StatusNotFound, backToWebhooks)
-}
-
-func TestErrorPage_UnknownPath(t *testing.T) {
-	t.Parallel()
-
-	env := newTestEnv(t)
-
-	userID, _ := env.seedUser(t, "owner", "somepassword")
-	cookies := env.authCookies(t, userID, "owner")
-
-	assertErrorPage(
-		t, env.get("/no-such-page", nil),
-		http.StatusNotFound, backToSignIn,
-	)
-
-	// Outside every route group there is no form token, so the
-	// page leaves out the logout form rather than offer one that
-	// would be refused.
-	w := env.get("/no-such-page", cookies)
-	assertErrorPage(t, w, http.StatusNotFound, backToWebhooks)
-	assert.NotContains(t, w.Body.String(), `action="/pages/logout"`)
-
-	// Inside a route group the page has a token, and logout works.
-	wh := env.seedWebhook(t, userID)
-	w = env.get("/source/"+wh.ID+"/no-such-page", cookies)
-	assertErrorPage(t, w, http.StatusNotFound, backToWebhooks)
-	assert.Contains(t, w.Body.String(), `action="/pages/logout"`)
-}
-
-func TestErrorPage_BadCSRFToken(t *testing.T) {
-	t.Parallel()
-
-	env := newTestEnv(t)
-
-	form := url.Values{}
-	form.Set("username", "someone")
-	form.Set("password", "irrelevant")
-	form.Set("csrf_token", "not-a-token")
-
-	assertErrorPage(
-		t, env.post("/pages/login", form, nil),
-		http.StatusForbidden, backToSignIn,
-	)
-
-	userID, _ := env.seedUser(t, "owner", "somepassword")
-	cookies := env.authCookies(t, userID, "owner")
-	wh := env.seedWebhook(t, userID)
-
-	edit := url.Values{}
-	edit.Set("name", "renamed")
-
-	assertErrorPage(
-		t, env.post("/source/"+wh.ID+"/edit", edit, cookies),
-		http.StatusForbidden, backToWebhooks,
-	)
-}
-
-// TestErrorPage_PanicOnAdminPage sends a panicking handler in an
-// admin page route group through the real router, with error
-// tracking on: the client gets the 500 error page, and the tracker
-// still gets the panic, once. The same panic outside the admin page
-// route groups keeps the plain 500.
-func TestErrorPage_PanicOnAdminPage(t *testing.T) {
-	t.Parallel()
-
-	env := newTestEnv(t)
-
-	transport := &captureTransport{}
-
-	opts := server.SentryClientOptionsForTest(
-		"https://public@sentry.invalid/1", "webhooker-test",
-	)
-	opts.Transport = transport
-
-	client, err := sentry.NewClient(opts)
-	require.NoError(t, err)
-
-	serve := func(router http.Handler, path string) *httptest.ResponseRecorder {
-		req := httptest.NewRequestWithContext(
-			sentry.SetHubOnContext(
-				context.Background(),
-				sentry.NewHub(client, sentry.NewScope()),
-			),
-			http.MethodGet, path, nil,
-		)
-
-		w := httptest.NewRecorder()
-		router.ServeHTTP(w, req)
-
-		return w
-	}
-
-	w := serve(
-		server.NewRouterWithPageProbeForTest(
-			env.log.Get(), env.cfg, env.mw, env.hnd,
-			true, panicProbeHandler,
-		),
-		server.PageProbePattern,
-	)
-	assertErrorPage(t, w, http.StatusInternalServerError, backToSignIn)
-
-	w = serve(
-		server.NewRouterWithProbeForTest(
-			env.log.Get(), env.cfg, env.mw, env.hnd,
-			true, panicProbeHandler,
-		),
-		server.ProbePattern,
-	)
-	assert.Equal(t, http.StatusInternalServerError, w.Code)
-	assert.Equal(t, "Internal Server Error\n", w.Body.String())
-
-	require.Len(t, transport.events, 2)
-
-	for _, event := range transport.events {
-		assert.Contains(t, marshalEvent(t, event), panicProbeMarker)
-	}
-}
-
-// TestErrorPage_ReceiverStaysPlain pins that the error page is for
-// the web UI only: a sender posting to an entrypoint that does not
-// exist still gets the plain-text answer.
-func TestErrorPage_ReceiverStaysPlain(t *testing.T) {
-	t.Parallel()
-
-	// newTestEnv leaves the receiver rate limit at zero, which
-	// refuses every request before it reaches the receiver.
-	env := newTestEnvWithConfig(t, &config.Config{
-		DataDir:           t.TempDir(),
-		Environment:       config.EnvironmentDev,
-		ReceiverRateLimit: 10,
-	})
-
-	w := env.post("/webhook/no-such-entrypoint", url.Values{}, nil)
-
-	assert.Equal(t, http.StatusNotFound, w.Code)
-	assert.Equal(t, "404 page not found\n", w.Body.String())
-}

internal/server/export_test.go

@@ -5,7 +5,6 @@ import (
 	"net/http"
 
 	"github.com/getsentry/sentry-go"
-	"github.com/go-chi/chi"
 	"sneak.berlin/go/webhooker/internal/config"
 	"sneak.berlin/go/webhooker/internal/handlers"
 	"sneak.berlin/go/webhooker/internal/middleware"
@@ -102,39 +101,3 @@ func NewRouterWithProbeForTest(
 
 	return s.router
 }
-
-// PageProbePattern is where NewRouterWithPageProbeForTest serves its
-// probe: inside the /pages route group, the admin page group a
-// request reaches without signing in.
-const PageProbePattern = "/pages/probe"
-
-// NewRouterWithPageProbeForTest is NewRouterWithProbeForTest with the
-// probe added to the /pages route group once SetupRoutes has built
-// it, so the probe runs behind that group's own middleware exactly as
-// the group's real routes do.
-func NewRouterWithPageProbeForTest(
-	log *slog.Logger,
-	cfg *config.Config,
-	mw *middleware.Middleware,
-	h *handlers.Handlers,
-	sentryEnabled bool,
-	probe http.HandlerFunc,
-) http.Handler {
-	s := &Server{
-		log:    log,
-		mw:     mw,
-		h:      h,
-		params: ServerParams{Config: cfg},
-	}
-	s.sentryEnabled.Store(sentryEnabled)
-	s.SetupRoutes()
-
-	for _, route := range s.router.Routes() {
-		pages, ok := route.SubRoutes.(chi.Router)
-		if ok && route.Pattern == "/pages/*" {
-			pages.Get("/probe", probe)
-		}
-	}
-
-	return s.router
-}

internal/server/routes.go

@@ -15,10 +15,9 @@ import (
 // bytes) for form POST endpoints. 1 MB is generous for any form
 // submission while preventing abuse from oversized payloads.
 //
-// The four admin page route groups below (/pages, /user/{username},
+// Every route group below installs MaxBodySize(maxFormBodySize) as
-// /sources and /source/{sourceID}) install MaxBodySize(maxFormBodySize)
+// its FIRST middleware, ahead of both CSRF and RequireAuth. Both
-// right after their recoverer and error reporting, ahead of both CSRF
+// orderings are deliberate.
-// and RequireAuth. Both orderings are deliberate.
 //
 // Ahead of CSRF because gorilla/csrf parses the form. The cap has to
 // be installed before anything reads the body, or the parse runs
@@ -47,14 +46,6 @@ const requestTimeout = 60 * time.Second
 // server's router.
 func (s *Server) SetupRoutes() {
 	s.router = chi.NewRouter()
-
-	// An unknown path gets the error page. Registered before the
-	// global middleware, because chi wraps a not-found handler in the
-	// middleware already on its router, which would then run twice.
-	// The route groups below wrap it in their own middleware the same
-	// way; running theirs twice is harmless.
-	s.router.NotFound(s.h.HandleErrorPage(http.StatusNotFound))
-
 	s.setupGlobalMiddleware()
 	s.setupRoutes()
 }
@@ -78,33 +69,23 @@ func (s *Server) setupGlobalMiddleware() {
 	// Panic recovery, deliberately here rather than first. It has to
 	// run inside every middleware that observes the response, so the
 	// 500 it writes is the status the access log records and the
-	// metrics count, and outside the sentryhttp handler, whose
+	// metrics count, and outside the sentryhttp handler below, whose
 	// Repanic option needs something further out to catch what it
 	// re-raises. chi's own middleware.Recoverer held the first slot
 	// until it was measured: on a current Go release it crashes
 	// inside its stack pretty-printer instead of recovering, so the
 	// connection dropped and the original panic was never reported.
 	// See https://git.eeqj.de/sneak/webhooker/issues/187.
-	s.recoverPanics(s.router, nil)
+	s.router.Use(s.mw.Recoverer())
-}
-
-// recoverPanics installs on r the recoverer, answering a panic with
-// page (a plain 500 when page is nil), and inside it the Sentry error
-// reporting (if SENTRY_DSN is set). Repanic is true so panics still
-// bubble up to the recoverer.
-//
-// Each admin page route group installs its own, with the error page,
-// as its first middleware. A panic there is logged, reported and
-// answered inside the group and never reaches the global recoverer,
-// which keeps the plain 500 for every other route.
-func (s *Server) recoverPanics(r chi.Router, page http.Handler) {
-	r.Use(s.mw.Recoverer(page))
 
+	// Sentry error reporting (if SENTRY_DSN is set). Repanic is
+	// true so panics still bubble up to the Recoverer middleware
+	// registered immediately above.
 	if s.sentryEnabled.Load() {
 		sentryHandler := sentryhttp.New(sentryhttp.Options{
 			Repanic: true,
 		})
-		r.Use(sentryHandler.Handle)
+		s.router.Use(sentryHandler.Handle)
 	}
 }
 
@@ -166,13 +147,10 @@ func (s *Server) setupRoutes() {
 
 func (s *Server) setupPageRoutes() {
 	s.router.Route("/pages", func(r chi.Router) {
-		s.recoverPanics(
-			r, s.h.HandleErrorPage(http.StatusInternalServerError),
-		)
 		// MaxBodySize precedes CSRF and RequireAuth deliberately;
 		// see maxFormBodySize for why, and for what it costs.
 		r.Use(s.mw.MaxBodySize(maxFormBodySize))
-		r.Use(s.mw.CSRF(s.h.HandleErrorPage(http.StatusForbidden)))
+		r.Use(s.mw.CSRF())
 		r.Use(s.mw.NoCache())
 
 		// The login POST carries no pre-emptive rate limiter. Behind
@@ -191,13 +169,10 @@ func (s *Server) setupPageRoutes() {
 
 func (s *Server) setupUserRoutes() {
 	s.router.Route("/user/{username}", func(r chi.Router) {
-		s.recoverPanics(
-			r, s.h.HandleErrorPage(http.StatusInternalServerError),
-		)
 		// MaxBodySize precedes CSRF and RequireAuth deliberately;
 		// see maxFormBodySize for why, and for what it costs.
 		r.Use(s.mw.MaxBodySize(maxFormBodySize))
-		r.Use(s.mw.CSRF(s.h.HandleErrorPage(http.StatusForbidden)))
+		r.Use(s.mw.CSRF())
 		r.Use(s.mw.NoCache())
 		r.Use(s.mw.RequireAuth())
 		r.Get("/", s.h.HandleProfile())
@@ -209,13 +184,10 @@ func (s *Server) setupUserRoutes() {
 
 func (s *Server) setupSourceRoutes() {
 	s.router.Route("/sources", func(r chi.Router) {
-		s.recoverPanics(
-			r, s.h.HandleErrorPage(http.StatusInternalServerError),
-		)
 		// MaxBodySize precedes CSRF and RequireAuth deliberately;
 		// see maxFormBodySize for why, and for what it costs.
 		r.Use(s.mw.MaxBodySize(maxFormBodySize))
-		r.Use(s.mw.CSRF(s.h.HandleErrorPage(http.StatusForbidden)))
+		r.Use(s.mw.CSRF())
 		r.Use(s.mw.NoCache())
 		r.Use(s.mw.RequireAuth())
 		r.Get("/", s.h.HandleSourceList())
@@ -224,13 +196,10 @@ func (s *Server) setupSourceRoutes() {
 	})
 
 	s.router.Route("/source/{sourceID}", func(r chi.Router) {
-		s.recoverPanics(
-			r, s.h.HandleErrorPage(http.StatusInternalServerError),
-		)
 		// MaxBodySize precedes CSRF and RequireAuth deliberately;
 		// see maxFormBodySize for why, and for what it costs.
 		r.Use(s.mw.MaxBodySize(maxFormBodySize))
-		r.Use(s.mw.CSRF(s.h.HandleErrorPage(http.StatusForbidden)))
+		r.Use(s.mw.CSRF())
 		r.Use(s.mw.NoCache())
 		r.Use(s.mw.RequireAuth())
 		r.Get("/", s.h.HandleSourceDetail())

script/test

@@ -22,6 +22,11 @@
 # The one figure above 90s is GOMAXPROCS 1, a synthetic core floor rather than
 # a condition CI runs under. If a CPU-limited runner ever puts a real run near
 # 67s, that is the datum to revisit the org figure with.
+#
+# -p 4 -parallel 8 keep the run under 2 GB of memory: at most four test
+# binaries build or run at once, each with at most eight parallel tests. Under
+# -race every test binary and every link costs a few hundred MB, so the
+# defaults (one per core) add up to several GB on a many-core host.
 set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
@@ -29,7 +34,7 @@ ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 main() {
     cd "$ROOT"
     "$ROOT/script/assets"
-    go test -v -race -timeout 90s ./...
+    go test -v -race -p 4 -parallel 8 -timeout 90s ./...
 }
 
 main "$@"

templates/error.html

@@ -1,15 +0,0 @@
-{{template "base" .}}
-
-{{define "title"}}{{.StatusText}} - Webhooker{{end}}
-
-{{define "content"}}
-<div class="max-w-4xl mx-auto px-6 py-12">
-    <h1 class="text-2xl font-medium text-gray-900 mb-4">{{.Status}} {{.StatusText}}</h1>
-    <p class="text-gray-600 mb-6">{{.Message}}</p>
-    {{if .User}}
-    <a href="/sources" class="btn-secondary">Back to webhooks</a>
-    {{else}}
-    <a href="/pages/login" class="btn-primary">Sign in</a>
-    {{end}}
-</div>
-{{end}}

templates/navbar.html

@@ -24,14 +24,10 @@
                 </svg>
                 {{.User.Username}}
             </a>
-            {{/* An error page can be served before a form token is issued,
-                 and a logout without one is refused. */}}
-            {{if .CSRFToken}}
             <form method="POST" action="/pages/logout" class="inline">
                 <input type="hidden" name="csrf_token" value="{{.CSRFToken}}">
                 <button type="submit" class="btn-text">Logout</button>
             </form>
-            {{end}}
             {{else}}
             <a href="/pages/login" class="btn-primary">Login</a>
             {{end}}
@@ -44,12 +40,10 @@
             {{if .User}}
             <a href="/sources" class="btn-text w-full text-left">Webhooks</a>
             <a href="/user/{{.User.Username}}" class="btn-text w-full text-left">Profile</a>
-            {{if .CSRFToken}}
             <form method="POST" action="/pages/logout">
                 <input type="hidden" name="csrf_token" value="{{.CSRFToken}}">
                 <button type="submit" class="btn-text w-full text-left">Logout</button>
             </form>
-            {{end}}
             {{else}}
             <a href="/pages/login" class="btn-primary w-full">Login</a>
             {{end}}

templates/source_detail.html

@@ -24,6 +24,8 @@
         </div>
     </div>
 
+    {{template "webhook_stats" .}}
+
     <div class="grid grid-cols-1 lg:grid-cols-2 gap-6">
         <!-- Entrypoints -->
         <div class="card">

templates/webhook_stats.html

@@ -0,0 +1,95 @@
+{{define "webhook_stats"}}
+<!-- Statistics pane at the top of the webhook page. -->
+<div class="card mb-6">
+    <div class="p-4 border-b border-gray-200">
+        <h2 class="text-lg font-medium text-gray-900">Statistics</h2>
+    </div>
+    {{with .Stats}}
+    <div class="p-4 flex flex-wrap gap-6 text-sm border-b border-gray-200">
+        <div>
+            <span class="text-gray-500">Entrypoints</span>
+            <span class="font-medium text-gray-900">{{.Entrypoints}}</span>
+            <span class="text-gray-500">({{.ActiveEntrypoints}} active)</span>
+        </div>
+        <div>
+            <span class="text-gray-500">Targets</span>
+            <span class="font-medium text-gray-900">{{.Targets}}</span>
+            <span class="text-gray-500">({{.ActiveTargets}} active)</span>
+        </div>
+        <div>
+            <span class="text-gray-500">Deliveries in progress</span>
+            <span class="font-medium text-gray-900">{{.InProgress}}</span>
+        </div>
+        <div>
+            <span class="text-gray-500">Last event</span>
+            <span class="font-medium text-gray-900">{{with .LastEventAt}}{{.UTC.Format "2006-01-02 15:04:05 UTC"}}{{else}}none{{end}}</span>
+        </div>
+        <div>
+            <span class="text-gray-500">Retention</span>
+            <span class="font-medium text-gray-900">{{$.Webhook.RetentionLabel}}</span>
+        </div>
+    </div>
+    <div class="p-4 grid grid-cols-1 lg:grid-cols-2 gap-6 text-sm">
+        <div>
+            <table class="w-full text-center text-gray-900">
+                <thead>
+                    <tr class="border-b border-gray-200 text-xs text-gray-500 uppercase tracking-wide">
+                        <th></th>
+                        <th class="py-2 font-medium">Lifetime</th>
+                        <th class="py-2 font-medium">Within retention</th>
+                    </tr>
+                </thead>
+                <tbody>
+                    <tr>
+                        <td class="py-2 text-left text-gray-600">Events</td>
+                        <td class="py-2">{{.Lifetime.Events}}</td>
+                        <td class="py-2">{{.WithinRetention.Events}}</td>
+                    </tr>
+                    <tr>
+                        <td class="py-2 text-left text-gray-600">Deliveries</td>
+                        <td class="py-2">{{.Lifetime.Deliveries}}</td>
+                        <td class="py-2">{{.WithinRetention.Deliveries}}</td>
+                    </tr>
+                    <tr>
+                        <td class="py-2 text-left text-gray-600">Failures</td>
+                        <td class="py-2">{{.Lifetime.Failures}}</td>
+                        <td class="py-2">{{.WithinRetention.Failures}}</td>
+                    </tr>
+                </tbody>
+            </table>
+        </div>
+        <div>
+            <table class="w-full text-center text-gray-900">
+                <thead>
+                    <tr class="border-b border-gray-200 text-xs text-gray-500 uppercase tracking-wide">
+                        <th></th>
+                        <th class="py-2 font-medium">Last 10 minutes</th>
+                        <th class="py-2 font-medium">Last 24 hours</th>
+                    </tr>
+                </thead>
+                <tbody>
+                    <tr>
+                        <td class="py-2 text-left text-gray-600">Events</td>
+                        <td class="py-2">{{.Last10Minutes.Events}}</td>
+                        <td class="py-2">{{.Last24Hours.Events}}</td>
+                    </tr>
+                    <tr>
+                        <td class="py-2 text-left text-gray-600">Failures</td>
+                        <td class="py-2">{{.Last10Minutes.Failed}}</td>
+                        <td class="py-2">{{.Last24Hours.Failed}}</td>
+                    </tr>
+                    <tr>
+                        <td class="py-2 text-left text-gray-600">Failure percentage</td>
+                        <td class="py-2">{{.Last10Minutes.FailurePercent}}</td>
+                        <td class="py-2">{{.Last24Hours.FailurePercent}}</td>
+                    </tr>
+                </tbody>
+            </table>
+            <p class="mt-2 text-xs text-gray-500">Failure percentage is the failed deliveries out of all deliveries that finished in the window. Deliveries still pending or retrying are not counted.</p>
+        </div>
+    </div>
+    {{else}}
+    <div class="p-4 text-sm text-gray-500">The statistics could not be read.</div>
+    {{end}}
+</div>
+{{end}}