README.md

@@ -1127,7 +1127,7 @@ 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`, `EventTotals`, `TargetTotals`
+  `DeliveryResult`, `EventTotals`, `TargetTotals`, `EntrypointTotals`
 - each archive database on every open and reopen
 
 There is no schema version table, no migration ledger, and no down
@@ -1531,6 +1531,9 @@ tier** (event ingestion, delivery, and logging).
 │  ┌──────────────┐  (one row per target: running counts      │
 │  │ TargetTotals │   of its deliveries)                      │
 │  └──────────────┘                                           │
+│  ┌──────────────────┐  (one row per entrypoint: when the    │
+│  │ EntrypointTotals │   last event arrived on its URL)      │
+│  └──────────────────┘                                       │
 └─────────────────────────────────────────────────────────────┘
 ```
 
@@ -1644,6 +1647,11 @@ different event sources that all feed into the same processing pipeline
 (e.g., one entrypoint for GitHub, another for Stripe, both routing to
 the same targets).
 
+The webhook page shows, for each entrypoint, when the last event arrived
+on its URL, which retention leaves in place, or "never" if none ever has,
+and how many events arrived on it within the webhook's retention period.
+A resubmitted event did not arrive on the URL and counts in neither.
+
 #### Target
 
 A delivery destination for events. Each target defines where and how
@@ -1853,10 +1861,11 @@ retries) is individually logged for full observability.
 
 **Relations:** Belongs to Delivery.
 
-#### EventTotals and TargetTotals
+#### EventTotals, TargetTotals and EntrypointTotals
 
 Running counts in each event database, read by the statistics pane at the
-top of the webhook page and by the webhook list. `EventTotals` is one row:
+top of the webhook page and by the webhook list, and each entrypoint's last
+event, read by the webhook page's entrypoint list. `EventTotals` is one row:
 
 | Field            | Type      | Description |
 | ---------------- | --------- | ----------- |
@@ -1875,18 +1884,26 @@ top of the webhook page and by the webhook list. `EventTotals` is one row:
 | `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
+`EntrypointTotals` is one row per entrypoint, created by the first event
-counts. The pane's lifetime events are `events`, and its lifetime
+that arrives on its URL:
-deliveries and failures are `deliveries` and `failed` summed over the
+
-targets; each figure within retention is the same less what retention
+| Field           | Type      | Description |
-removed, so neither needs the rows themselves. Its last event is
+| --------------- | --------- | ----------- |
-`last_event_at`, written in the transaction that stores the event, so it
+| `entrypoint_id` | UUID      | The entrypoint (primary key) |
-still shows once retention has removed every event. Its last-10-minutes and
+| `last_event_at` | timestamp | When the newest event arrived on its URL; a resubmitted event leaves it as it is, and so does retention |
-last-24-hours figures are counted from the `events` and `deliveries`
+
-indexes over just that window, the deliveries in one query grouped by
+Each count changes in the transaction that writes or deletes the rows it counts,
-target. Its failure percentage for a window is the deliveries that became
+and each `last_event_at` in the transaction that stores the event. The pane's
-`failed` in it out of all that became `delivered` or `failed` in it, and
+lifetime events are `events`, and its lifetime deliveries and failures are
-a dash when none did.
+`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` in `EventTotals`, so it still shows once
+retention has removed every event; each entrypoint's last event, from
+`EntrypointTotals`, does too. 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.
 
 The webhook list at `/hooks` shows three of the pane's figures for each
 webhook: its events within retention and its last event, both from
@@ -1908,26 +1925,31 @@ tags, so `AutoMigrate` creates them on a fresh database:
 | `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`  | The webhook page's statistics, which count recent events |
 | `events`           | `resubmitted_from_id`, `deleted_at` | The event log, which counts the events resubmitted from each event on a page |
+| `events`           | `entrypoint_id`, `deleted_at`, `resubmitted_from_id`, `created_at` | The webhook page's entrypoint list, which counts the events that arrived on each entrypoint's URL within the retention period |
 | `events`           | `created_at`                | Retention, which selects expired events by age |
 
-GORM's soft delete adds `deleted_at IS NULL` to these queries; retention
+GORM's soft delete adds `deleted_at IS NULL` to these queries; retention leaves
-leaves it out. SQLite keeps no statistics on these tables, and without them it
+it out. SQLite keeps no statistics on these tables, and without them it rates
-rates the `deleted_at` index, which every live row matches, above an index on
+the `deleted_at` index, which every live row matches, above an index on a column
-a column matched against several values or compared with a range. So every
+matched against several values or compared with a range. So every index but the
-index but the last also covers `deleted_at`. It comes second in the `event_id`
+last also covers `deleted_at`. It comes second in the `event_id` and
-and `delivery_id` indexes, so that retention can use them without it. The event
+`delivery_id` indexes, so that retention can use them without it. The event
 log's count, the one query on the `resubmitted_from_id` index, always carries
-`deleted_at IS NULL` and uses both columns. In the statistics' `events` index
+`deleted_at IS NULL` and uses both columns. The entrypoint list's count, the one
-`deleted_at` comes first, because they compare `created_at` with a range (`>=`)
+query on the `entrypoint_id` index, uses all four, `resubmitted_from_id IS NULL`
-and SQLite narrows by a range only on the last column it uses.
+leaving out resubmitted copies and `created_at` last because it compares it with
+a range (`>=`). In the statistics' `events` index `deleted_at` comes first,
+because they compare `created_at` with a range (`>=`) and SQLite narrows by a
+range only on the last column it uses.
 
 #### Common Fields
 
-Every entity except `Setting`, `EventTotals` and `TargetTotals` includes
+Every entity except `Setting`, `EventTotals`, `TargetTotals` and
-these fields from `BaseModel`. `Setting` is a bare key-value row with no
+`EntrypointTotals` includes these fields from `BaseModel`. `Setting` is a bare
-`id`, no timestamps and no soft delete, and the two totals tables hold
+key-value row with no `id`, no timestamps and no soft delete. Of the three
-counts, plus `last_event_at` in `event_totals`, keyed by a numeric `id`
+totals tables, `event_totals` holds counts and `last_event_at`, keyed by a
-and by `target_id`:
+numeric `id`; `target_totals` holds counts, keyed by `target_id`; and
+`entrypoint_totals` holds `last_event_at`, keyed by `entrypoint_id`:
 
 | Field        | Type      | Description |
 | ------------ | --------- | ----------- |
@@ -1969,8 +1991,9 @@ 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,
+- **EventTotals**, **TargetTotals** and **EntrypointTotals** — running
-  the deliveries per target, kept through retention
+  counts of the above, the deliveries per target, and each entrypoint's
+  last event, kept through retention
 
 Per-webhook databases are created automatically when a webhook is
 created. They are managed by the `WebhookDBManager` component, which
@@ -3035,7 +3058,7 @@ 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_totals.go    # EventTotals, TargetTotals and EntrypointTotals (per-webhook DB)
 │   │   ├── model_apikey.go    # APIKey entity
 │   │   ├── password.go        # Argon2id hashing and verification
 │   │   ├── retention.go       # Retention reaper (per-webhook event expiry)
@@ -3311,9 +3334,9 @@ check, see [The login endpoint](#the-login-endpoint).
   `ENTRYPOINT` script, which sets the data directory's owner and mode
   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
+- GORM soft deletes on every entity that carries `BaseModel`, which is all of
-  all of them but `Setting`, `EventTotals` and `TargetTotals` (data
+  them but `Setting`, `EventTotals`, `TargetTotals` and `EntrypointTotals`
-  preserved for audit)
+  (data preserved for audit)
 
 ### Shutdown
 

internal/database/event_tier_indexes_test.go

@@ -233,6 +233,43 @@ func TestResubmitCountUsesItsIndex(t *testing.T) {
 			"(resubmitted_from_id=? AND deleted_at=?)")
 }
 
+// TestEntrypointEventsUseTheirIndex does the same for the webhook
+// page's count, for each entrypoint, of the events that arrived on its
+// URL since the retention cutoff (addEntrypointEvents in the
+// handlers), which must come from the index alone. It passes 25
+// entrypoints, as TestResubmitCountUsesItsIndex passes 25 events.
+func TestEntrypointEventsUseTheirIndex(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})
+
+	entrypoints := make([]string, 25)
+	for i := range entrypoints {
+		entrypoints[i] = uuid.New().String()
+	}
+
+	var rows []struct{ Events int }
+
+	assertPlanUses(t, db, dry.Model(&database.Event{}).
+		Select("entrypoint_id, count(*) AS events").
+		Where("entrypoint_id IN ? AND resubmitted_from_id IS NULL",
+			entrypoints).
+		Where("created_at >= ?", time.Now()).
+		Group("entrypoint_id").Find(&rows),
+		"COVERING INDEX idx_events_entrypoint_id "+
+			"(entrypoint_id=? AND deleted_at=? AND "+
+			"resubmitted_from_id=? AND created_at>?)")
+}
+
 // assertPlanUses asserts that SQLite's plan for a statement GORM built
 // in a dry run, run with the same SQL and arguments GORM would send,
 // names each of the given indexes.

internal/database/model_event.go

@@ -20,12 +20,15 @@ type Event struct {
 	// has no deleted_at condition and uses the index on created_at
 	// alone. The other tables keep the unindexed BaseModel created_at.
 	// DeletedAt is also the second column of the resubmitted_from_id
-	// index, for the reason DeliveryResult gives.
+	// index, for the reason DeliveryResult gives. The entrypoint_id
-	CreatedAt time.Time      `gorm:"index;index:idx_events_deleted_at_created_at,priority:2"                                           json:"createdAt"`
+	// index, for the webhook page's entrypoint list, has it second too,
-	DeletedAt gorm.DeletedAt `gorm:"index:idx_events_deleted_at_created_at,priority:1;index:idx_events_resubmitted_from_id,priority:2" json:"deletedAt,omitzero"`
+	// resubmitted_from_id third, and created_at last, which the list
+	// compares with a range.
+	CreatedAt time.Time      `gorm:"index;index:idx_events_deleted_at_created_at,priority:2;index:idx_events_entrypoint_id,priority:4"                                           json:"createdAt"`
+	DeletedAt gorm.DeletedAt `gorm:"index:idx_events_deleted_at_created_at,priority:1;index:idx_events_resubmitted_from_id,priority:2;index:idx_events_entrypoint_id,priority:2" json:"deletedAt,omitzero"`
 
 	WebhookID    string `gorm:"type:uuid;not null"                                           json:"webhookId"`
-	EntrypointID string `gorm:"type:uuid;not null" json:"entrypointId"`
+	EntrypointID string `gorm:"type:uuid;not null;index:idx_events_entrypoint_id,priority:1" json:"entrypointId"`
 
 	// Request data
 	Method      string `gorm:"not null"    json:"method"`
@@ -44,7 +47,7 @@ type Event struct {
 	// existed. It is not a foreign key: the source event can be
 	// reaped by retention while its copies remain, and the id is
 	// kept as the record of where the copy came from either way.
-	ResubmittedFromID *string `gorm:"type:uuid;index:idx_events_resubmitted_from_id,priority:1" json:"resubmittedFromId,omitempty"`
+	ResubmittedFromID *string `gorm:"type:uuid;index:idx_events_resubmitted_from_id,priority:1;index:idx_events_entrypoint_id,priority:3" json:"resubmittedFromId,omitempty"`
 
 	// Relations. No model marshals the record it belongs to, so
 	// Webhook and Entrypoint are left out of the JSON.

internal/database/model_totals.go

@@ -52,6 +52,21 @@ func (TargetTotals) TableName() string {
 	return "target_totals"
 }
 
+// EntrypointTotals is one row per entrypoint, created by the first
+// event that arrives on its URL: when the newest such event arrived,
+// which retention leaves as it is. A resubmitted copy did not arrive
+// on the URL and does not change it.
+type EntrypointTotals struct {
+	EntrypointID string `gorm:"type:uuid;primaryKey"`
+
+	LastEventAt time.Time `gorm:"not null"`
+}
+
+// TableName names the table AddEntrypointTotals updates.
+func (EntrypointTotals) TableName() string {
+	return "entrypoint_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
@@ -97,3 +112,25 @@ func AddTargetTotals(tx *gorm.DB, add TargetTotals) error {
 
 	return nil
 }
+
+// AddEntrypointTotals records add.LastEventAt as when the newest event
+// arrived on the URL of the entrypoint add.EntrypointID names, creating
+// its row the first time. Call it on the transaction that stores the
+// event.
+func AddEntrypointTotals(tx *gorm.DB, add EntrypointTotals) error {
+	err := tx.Exec(
+		`INSERT INTO entrypoint_totals (entrypoint_id, last_event_at)
+		VALUES (?, ?)
+		ON CONFLICT (entrypoint_id) DO UPDATE SET
+			last_event_at = excluded.last_event_at`,
+		add.EntrypointID, add.LastEventAt,
+	).Error
+	if err != nil {
+		return fmt.Errorf(
+			"adding to totals of entrypoint %s: %w",
+			add.EntrypointID, err,
+		)
+	}
+
+	return nil
+}

internal/database/model_webhook.go

@@ -111,6 +111,13 @@ func (w *Webhook) RetainsForever() bool {
 	return retainsForever(w.RetentionDays)
 }
 
+// RetentionCutoff returns the time before which this webhook's events
+// have expired, as the reaper computes it, and false when the webhook
+// retains them forever.
+func (w *Webhook) RetentionCutoff(now time.Time) (time.Time, bool) {
+	return retentionCutoff(now, w.RetentionDays)
+}
+
 // RetentionLabel returns the webhook's retention policy as display
 // text, so that no template has to know about the sentinel value.
 func (w *Webhook) RetentionLabel() string {

internal/database/models.go

@@ -3,7 +3,7 @@ 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, EventTotals,
-// TargetTotals) live in
+// TargetTotals, EntrypointTotals) live in
 // per-webhook dedicated databases managed by WebhookDBManager.
 func (d *Database) Migrate() error {
 	return d.db.AutoMigrate(

internal/database/webhook_db_manager.go

@@ -49,7 +49,7 @@ var ErrSidecarNotRemoved = errors.New(
 // WebhookDBManager manages per-webhook SQLite database files
 // for event storage. Each webhook gets its own dedicated
 // database containing Events, Deliveries, DeliveryResults and the
-// running totals of them (EventTotals, TargetTotals).
+// running totals of them (EventTotals, TargetTotals, EntrypointTotals).
 // Database connections are opened lazily and cached.
 type WebhookDBManager struct {
 	dataDir string
@@ -381,7 +381,7 @@ func (m *WebhookDBManager) openDB(
 	// Run migrations for event-tier models only
 	err = db.AutoMigrate(
 		&Event{}, &Delivery{}, &DeliveryResult{},
-		&EventTotals{}, &TargetTotals{},
+		&EventTotals{}, &TargetTotals{}, &EntrypointTotals{},
 	)
 	if err != nil {
 		_ = sqlDB.Close()

internal/handlers/entrypoint_view.go

@@ -1,6 +1,11 @@
 package handlers
 
 import (
+	"fmt"
+	"time"
+
+	"github.com/dustin/go-humanize"
+	"gorm.io/gorm"
 	"sneak.berlin/go/webhooker/internal/database"
 )
 
@@ -11,6 +16,21 @@ type EntrypointView struct {
 	Path        string
 	Description string
 	Active      bool
+
+	// Events is how many events arrived on the entrypoint's URL within
+	// the webhook's retention period. LastEvent is when the newest
+	// event ever to arrive on it did, relative, and LastEventUTC the
+	// full time; both are empty when none ever did.
+	Events       int64
+	LastEvent    string
+	LastEventUTC string
+}
+
+// entrypointEvents is one entrypoint's count read by
+// addEntrypointEvents.
+type entrypointEvents struct {
+	EntrypointID string
+	Events       int64
 }
 
 // NewEntrypointViews projects entrypoints for rendering.
@@ -32,3 +52,60 @@ func NewEntrypointViews(
 
 	return views
 }
+
+// addEntrypointEvents fills in each view's event figures from the
+// webhook's event database: when the last event arrived on its URL,
+// from its EntrypointTotals row, and how many events arrived on it
+// since the webhook's retention cutoff, counted in one query over the
+// events' entrypoint_id index. Resubmitted copies did not arrive on
+// the URL and are left out of both.
+func addEntrypointEvents(
+	webhookDB *gorm.DB,
+	webhook *database.Webhook,
+	views []EntrypointView,
+	now time.Time,
+) error {
+	ids := make([]string, len(views))
+	byID := make(map[string]*EntrypointView, len(views))
+
+	for i := range views {
+		ids[i] = views[i].ID
+		byID[views[i].ID] = &views[i]
+	}
+
+	var totals []database.EntrypointTotals
+
+	err := webhookDB.Where("entrypoint_id IN ?", ids).Find(&totals).Error
+	if err != nil {
+		return fmt.Errorf("reading entrypoint totals: %w", err)
+	}
+
+	query := webhookDB.Model(&database.Event{}).
+		Select("entrypoint_id, count(*) AS events").
+		Where("entrypoint_id IN ? AND resubmitted_from_id IS NULL", ids)
+
+	cutoff, finite := webhook.RetentionCutoff(now)
+	if finite {
+		query = query.Where("created_at >= ?", cutoff)
+	}
+
+	var counts []entrypointEvents
+
+	err = query.Group("entrypoint_id").Find(&counts).Error
+	if err != nil {
+		return fmt.Errorf("counting events by entrypoint: %w", err)
+	}
+
+	for _, row := range totals {
+		view := byID[row.EntrypointID]
+		view.LastEvent = humanize.Time(row.LastEventAt)
+		view.LastEventUTC =
+			row.LastEventAt.UTC().Format(time.DateTime) + " UTC"
+	}
+
+	for _, row := range counts {
+		byID[row.EntrypointID].Events = row.Events
+	}
+
+	return nil
+}

internal/handlers/entrypoint_view_test.go

@@ -0,0 +1,197 @@
+package handlers_test
+
+import (
+	"net/http"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"gorm.io/gorm/clause"
+	"sneak.berlin/go/webhooker/internal/database"
+	"sneak.berlin/go/webhooker/internal/handlers"
+	"sneak.berlin/go/webhooker/internal/logger"
+	"sneak.berlin/go/webhooker/internal/session"
+)
+
+// entrypointRow returns the part of a rendered webhook page from an
+// entrypoint's URL to the next entrypoint's, which holds its figures.
+func entrypointRow(t *testing.T, page, entrypointID string) string {
+	t.Helper()
+
+	_, row, found := strings.Cut(page, `id="entrypoint-url-`+entrypointID+`"`)
+	require.True(t, found)
+
+	row, _, _ = strings.Cut(row, `id="entrypoint-url-`)
+
+	return row
+}
+
+// lastEventShown matches an entrypoint row's last event arriving at at.
+func lastEventShown(at time.Time) string {
+	return `Last Event:</span>\s*<span title="` +
+		at.UTC().Format(time.DateTime) + ` UTC">[^<]+</span>`
+}
+
+// eventsShown matches an entrypoint row's count of n events.
+func eventsShown(n int) string {
+	return `Events Within Retention:</span>\s*<span>` +
+		strconv.Itoa(n) + `</span>`
+}
+
+// TestHandleSourceDetail_ShowsEntrypointEvents proves each entrypoint
+// on the webhook page shows its own figures: how many events arrived
+// through it within the webhook's retention period, leaving out one
+// older than that, and when the newest arrived, or "never" for an
+// entrypoint with none.
+func TestHandleSourceDetail_ShowsEntrypointEvents(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 := &database.Webhook{
+		UserID: deleteTestUserID, Name: "figures", RetentionDays: 7,
+	}
+	require.NoError(t, db.DB().Omit(clause.Associations).Create(wh).Error)
+
+	webhookDB, err := dbMgr.GetDB(wh.ID)
+	require.NoError(t, err)
+
+	entrypoint := func() *database.Entrypoint {
+		ep := &database.Entrypoint{
+			WebhookID: wh.ID, Path: uuid.New().String(), Active: true,
+		}
+		require.NoError(t,
+			db.DB().Omit(clause.Associations).Create(ep).Error)
+
+		return ep
+	}
+
+	// event stores an event that arrived on ep's URL age ago and
+	// records it as ep's last event, as the receiver does.
+	event := func(ep *database.Entrypoint, age time.Duration) time.Time {
+		e := &database.Event{
+			WebhookID:    wh.ID,
+			EntrypointID: ep.ID,
+			Method:       http.MethodPost,
+		}
+		e.CreatedAt = time.Now().Add(-age)
+		require.NoError(t,
+			webhookDB.Omit(clause.Associations).Create(e).Error)
+		require.NoError(t, database.AddEntrypointTotals(webhookDB,
+			database.EntrypointTotals{
+				EntrypointID: ep.ID, LastEventAt: e.CreatedAt,
+			}))
+
+		return e.CreatedAt
+	}
+
+	busy, quiet, unused := entrypoint(), entrypoint(), entrypoint()
+
+	event(busy, 8*24*time.Hour) // older than the 7 days kept
+	event(busy, 3*time.Hour)
+	busyLast := event(busy, time.Hour)
+	quietLast := event(quiet, 2*24*time.Hour)
+
+	body := renderSourceDetailPage(t, h, sess, wh.ID)
+
+	assert.Regexp(t, lastEventShown(busyLast), entrypointRow(t, body, busy.ID))
+	assert.Regexp(t, eventsShown(2), entrypointRow(t, body, busy.ID))
+	assert.Regexp(t, lastEventShown(quietLast), entrypointRow(t, body, quiet.ID))
+	assert.Regexp(t, eventsShown(1), entrypointRow(t, body, quiet.ID))
+	assert.Regexp(t, `Last Event:</span>\s*<span>never</span>`,
+		entrypointRow(t, body, unused.ID))
+	assert.Regexp(t, eventsShown(0), entrypointRow(t, body, unused.ID))
+}
+
+// TestHandleSourceDetail_EntrypointLastEventSurvivesRetention checks
+// that once retention has removed every event that arrived on an
+// entrypoint's URL, the entrypoint still shows when the last one
+// arrived rather than "never".
+func TestHandleSourceDetail_EntrypointLastEventSurvivesRetention(
+	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: "swept", RetentionDays: 1,
+	}
+	require.NoError(t, db.DB().Omit(clause.Associations).Create(wh).Error)
+
+	ep := seedEntrypoint(t, db, wh.ID)
+	webhookDB, events := receiveEvents(t, h, dbMgr, wh.ID, ep.Path, 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))
+
+	row := entrypointRow(t, renderSourceDetailPage(t, h, sess, wh.ID), ep.ID)
+	assert.Regexp(t, lastEventShown(arrived), row)
+	assert.Regexp(t, eventsShown(0), row)
+}
+
+// TestHandleSourceDetail_ResubmitLeavesEntrypointFigures checks that a
+// resubmitted copy, which did not arrive on the entrypoint's URL,
+// changes neither the entrypoint's last event nor its count.
+func TestHandleSourceDetail_ResubmitLeavesEntrypointFigures(
+	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)
+	ep := seedEntrypoint(t, db, wh.ID)
+	webhookDB, events := receiveEvents(t, h, dbMgr, wh.ID, ep.Path, 1)
+	arrived := events[0].CreatedAt
+
+	require.Equal(t, http.StatusSeeOther,
+		postResubmit(t, h, sess, wh.ID, events[0].ID).Code)
+	require.Len(t, listEvents(t, webhookDB), 2)
+
+	var totals database.EntrypointTotals
+
+	require.NoError(t, webhookDB.Take(&totals).Error)
+	assert.True(t, arrived.Equal(totals.LastEventAt))
+
+	row := entrypointRow(t, renderSourceDetailPage(t, h, sess, wh.ID), ep.ID)
+	assert.Regexp(t, lastEventShown(arrived), row)
+	assert.Regexp(t, eventsShown(1), row)
+}

internal/handlers/source_management.go

@@ -485,6 +485,8 @@ func (h *Handlers) renderSourceDetail(
 		"webhook_id = ?", webhook.ID,
 	).Find(&targets)
 
+	entrypointViews := NewEntrypointViews(entrypoints)
+
 	var events []RecentEventView
 
 	if h.dbMgr.DBExists(webhook.ID) {
@@ -503,6 +505,15 @@ func (h *Handlers) renderSourceDetail(
 
 			return
 		}
+
+		err = addEntrypointEvents(
+			webhookDB, &webhook, entrypointViews, time.Now(),
+		)
+		if err != nil {
+			h.serverError(w, r, "failed to count entrypoint events", err)
+
+			return
+		}
 	}
 
 	scheme := "http"
@@ -523,7 +534,7 @@ func (h *Handlers) renderSourceDetail(
 		// Targets are projected to a display-safe view: a
 		// target's stored config blob holds a credential, and it
 		// must never reach a template.
-		"Entrypoints": NewEntrypointViews(entrypoints),
+		"Entrypoints": entrypointViews,
 		"Targets":     h.targetRows(&webhook, targets),
 		"Events":      events,
 		"BaseURL":     baseURL,

internal/handlers/webhook.go

@@ -326,6 +326,19 @@ func (h *Handlers) createAndFanOut(
 		return nil, nil, err
 	}
 
+	// A resubmitted copy did not arrive on its entrypoint's URL, so it
+	// leaves the entrypoint's last event as it is.
+	if src.ResubmittedFromID == nil {
+		err = database.AddEntrypointTotals(tx, database.EntrypointTotals{
+			EntrypointID: event.EntrypointID, LastEventAt: event.CreatedAt,
+		})
+		if err != nil {
+			tx.Rollback()
+
+			return nil, nil, err
+		}
+	}
+
 	err = tx.Commit().Error
 	if err != nil {
 		return nil, nil, fmt.Errorf(

templates/source_detail.html

@@ -97,6 +97,18 @@
                     </div>
                     <!-- The URL above is the entrypoint's credential:
                          anyone holding it can submit events. -->
+                    <div class="text-xs text-gray-500 mt-1">
+                        <span class="font-medium text-gray-700">Last Event:</span>
+                        {{if .LastEvent}}
+                        <span title="{{.LastEventUTC}}">{{.LastEvent}}</span>
+                        {{else}}
+                        <span>never</span>
+                        {{end}}
+                    </div>
+                    <div class="text-xs text-gray-500 mt-1">
+                        <span class="font-medium text-gray-700">Events Within Retention:</span>
+                        <span>{{.Events}}</span>
+                    </div>
                 </div>
                 {{else}}
                 <div class="p-4 text-sm text-gray-500">No entrypoints configured.</div>