Event log: show only the events with a failed or a pending delivery (closes #390)

The event log gains three links above the list: All, Failed (N) and
Pending (N), carried in a `show` query parameter; any other value shows
every event. Failed lists the events with a failed delivery, Pending
those with one pending or retrying, each once, under the full list's
50-row limit and order. A filtered list finds the matching deliveries
through `idx_deliveries_status`, looks up their events by ID and sorts
them, and reads the rows of only the events shown; its counts read the
deliveries alone. The line beside the heading says what a filter
counts, and Replay returns to the list it was pressed in. The README
and the comments naming the query parameters the service reads include
`show`.

Model: opus-5-5

internal/handlers/delivery_replay.go

@@ -329,15 +329,25 @@ func replayBody(body string) *string {
 }
 
 // redirectToEventLog redirects a replay or resubmit back to the event
-// log it was triggered from, carrying the outcome as its notice.
+// log it was triggered from, carrying the outcome as its notice. A
+// Replay form carries the list it was pressed in as show, so a replay
+// returns to the Failed or Pending list; a Resubmit form carries none,
+// so a resubmit returns to the full log, where its new event is the
+// newest.
 func redirectToEventLog(
 	w http.ResponseWriter,
 	r *http.Request,
 	webhook database.Webhook,
 	code noticeCode,
 ) {
-	http.Redirect(
-		w, r, withNotice("/hook/"+webhook.ID+"/events", code),
-		http.StatusSeeOther,
+	location := withNotice("/hook/"+webhook.ID+"/events", code)
+
+	show := r.PostFormValue(showParam)
+	if eventLogStatuses(show) != nil {
+		location += "&" + showParam + "=" + show
+	}
+
+	http.Redirect( //nolint:gosec // show is checked by eventLogStatuses
+		w, r, location, http.StatusSeeOther,
 	)
 }

internal/handlers/delivery_replay_test.go

@@ -1,6 +1,7 @@
 package handlers_test
 
 import (
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"strings"
@@ -471,6 +472,66 @@ func TestHandleDeliveryReplay_RefusesWhileEarlierReplayInFlight(
 	)
 }
 
+// TestHandleDeliveryReplay_ReturnsToTheListItWasPressedIn proves a
+// Replay pressed in the Failed list carries that list in its form and
+// returns to it, and that a show value the event log does not know
+// returns to the full log.
+func TestHandleDeliveryReplay_ReturnsToTheListItWasPressedIn(
+	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)
+	tgt := seedConfiguredTarget(
+		t, db, wh.ID, database.TargetTypeHTTP,
+		`{"url":"`+replayTargetURL+`"}`,
+	)
+
+	_, original := seedFailedDelivery(t, dbMgr, wh.ID, tgt.ID)
+
+	assert.Contains(t, renderSourceLogsPageWithQuery(
+		t, h, sess, wh.ID, "?show=failed",
+	), `name="show" value="failed"`)
+
+	// The second replay is refused, as the first is still queued.
+	for _, tc := range []struct{ show, location string }{
+		{"failed", "/hook/" + wh.ID +
+			"/events?notice=replay-queued&show=failed"},
+		{"made-up", "/hook/" + wh.ID + "/events?notice=replay-in-flight"},
+	} {
+		req := postRequest(
+			"/hook/"+wh.ID+"/deliveries/"+original.ID+"/replay",
+			authenticatedCookies(
+				t, sess, deleteTestUserID, deleteTestUsername,
+			),
+			map[string]string{
+				paramSourceID:   wh.ID,
+				paramDeliveryID: original.ID,
+			},
+		)
+		req.Body = io.NopCloser(strings.NewReader("show=" + tc.show))
+		req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+		w := httptest.NewRecorder()
+		h.HandleDeliveryReplay().ServeHTTP(w, req)
+
+		require.Equal(t, http.StatusSeeOther, w.Code, tc.show)
+		assert.Equal(t, tc.location, w.Header().Get("Location"), tc.show)
+	}
+}
+
 // TestHandleSourceLogs_RendersReplayControlAndBanner proves the action
 // reaches the page it belongs on: a finished delivery renders a POST
 // form carrying a CSRF token, and the outcome code a refusal redirects

internal/handlers/export_test.go

@@ -75,7 +75,7 @@ func (s *Handlers) LoadEventLogViewsForTest(
 	webhook database.Webhook,
 ) []EventLogView {
 	views, _, _ := s.loadEventsWithDeliveries(
-		w, newRequestForTest(), webhook, nil,
+		w, newRequestForTest(), webhook, nil, nil,
 	)
 
 	return views

internal/handlers/source_logs_test.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net/http"
 	"net/http/httptest"
+	"slices"
 	"strings"
 	"testing"
 	"time"
@@ -186,6 +187,152 @@ func TestHandleSourceLogs_ShowsFiftyNewestEvents(t *testing.T) {
 	assert.Contains(t, body, "50 most recent of 51 events")
 }
 
+// TestHandleSourceLogs_ShowsEventsByDeliveryStatus proves that the
+// Failed list holds exactly the events with a failed delivery, the
+// Pending list exactly those with a delivery pending or retrying, each
+// once, and any other show value every event; that each link, and the
+// line beside the heading, counts the events its list holds; and that
+// the shown link is marked.
+func TestHandleSourceLogs_ShowsEventsByDeliveryStatus(t *testing.T) {
+	t.Parallel()
+
+	f := newRecentEventsFixture(t)
+	target := seedTarget(t, f.db, f.webhook.ID, database.TargetTypeLog)
+	now := time.Now()
+
+	const (
+		failed    = database.DeliveryStatusFailed
+		delivered = database.DeliveryStatusDelivered
+		pending   = database.DeliveryStatusPending
+		retrying  = database.DeliveryStatusRetrying
+	)
+
+	// Each event is named by its content type. The first failed and
+	// was then replayed and delivered. The second failed, and so did
+	// its replay, and the fifth has one delivery pending and another
+	// retrying: each must still be listed and counted once.
+	events := []struct {
+		contentType string
+		deliveries  []database.DeliveryStatus
+	}{
+		{"application/x-failed", []database.DeliveryStatus{failed, delivered}},
+		{"application/x-failed-twice", []database.DeliveryStatus{failed, failed}},
+		{"application/x-pending", []database.DeliveryStatus{pending}},
+		{"application/x-retrying", []database.DeliveryStatus{retrying}},
+		{"application/x-pending-retrying", []database.DeliveryStatus{pending, retrying}},
+		{"application/x-delivered", []database.DeliveryStatus{delivered}},
+		{"application/x-no-delivery", nil},
+	}
+
+	all := make([]string, len(events))
+
+	for i, e := range events {
+		event := f.event(
+			t, e.contentType, "{}", now.Add(time.Duration(i)*time.Second),
+		)
+
+		for _, status := range e.deliveries {
+			f.delivery(t, event, target.ID, status)
+		}
+
+		all[i] = e.contentType
+	}
+
+	for _, tc := range []struct {
+		query   string
+		current string
+		heading string
+		listed  []string
+	}{
+		{"", "All", "7 total events", all},
+		{"?show=failed", "Failed (2)", "2 events with a failed delivery",
+			[]string{"application/x-failed", "application/x-failed-twice"}},
+		{"?show=pending", "Pending (3)",
+			"3 events with a delivery pending or retrying", []string{
+				"application/x-pending", "application/x-retrying",
+				"application/x-pending-retrying",
+			}},
+		{"?show=unknown", "All", "7 total events", all},
+	} {
+		body := renderSourceLogsPageWithQuery(
+			t, f.h, f.sess, f.webhook.ID, tc.query,
+		)
+
+		// One row per listed event, so with each listed event shown
+		// no event is listed twice.
+		assert.Equal(t, len(tc.listed),
+			strings.Count(body, `role="button"`), tc.query)
+
+		for _, contentType := range all {
+			assert.Equal(t,
+				slices.Contains(tc.listed, contentType),
+				strings.Contains(body, ">"+contentType+"<"),
+				tc.query+" "+contentType)
+		}
+
+		assert.Contains(t, body, ">"+tc.heading+"<", tc.query)
+		assert.Contains(t, body, "Failed (2)", tc.query)
+		assert.Contains(t, body, "Pending (3)", tc.query)
+		assert.Equal(t, 1, strings.Count(body, "aria-current"), tc.query)
+		assert.Contains(t, body,
+			`aria-current="page">`+tc.current+"</a>", tc.query)
+	}
+}
+
+// TestHandleSourceLogs_FilteredListShowsFiftyNewest proves a filtered
+// list holds the 50 newest matching events, as the full log does,
+// while its link and heading count every matching event.
+func TestHandleSourceLogs_FilteredListShowsFiftyNewest(t *testing.T) {
+	t.Parallel()
+
+	f := newRecentEventsFixture(t)
+	target := seedTarget(t, f.db, f.webhook.ID, database.TargetTypeLog)
+	base := time.Now().Add(-time.Hour)
+
+	for i := range 51 {
+		event := f.event(
+			t, fmt.Sprintf("application/x-failed-%02d", i), "{}",
+			base.Add(time.Duration(i)*time.Second),
+		)
+		f.delivery(t, event, target.ID, database.DeliveryStatusFailed)
+	}
+
+	// The newest event has no failed delivery.
+	f.event(t, "application/x-no-delivery", "{}", time.Now())
+
+	body := renderSourceLogsPageWithQuery(
+		t, f.h, f.sess, f.webhook.ID, "?show=failed",
+	)
+
+	assert.Equal(t, 50, strings.Count(body, `role="button"`))
+	assert.NotContains(t, body, "application/x-failed-00")
+	assert.NotContains(t, body, "application/x-no-delivery")
+	assert.Contains(t, body, "Failed (51)")
+	assert.Contains(t, body,
+		"50 most recent of 51 events with a failed delivery")
+}
+
+// TestHandleSourceLogs_EmptyFilteredList proves an empty filtered list
+// says that no event matches rather than that none was recorded.
+func TestHandleSourceLogs_EmptyFilteredList(t *testing.T) {
+	t.Parallel()
+
+	f := newRecentEventsFixture(t)
+	target := seedTarget(t, f.db, f.webhook.ID, database.TargetTypeLog)
+
+	f.delivery(
+		t, f.event(t, contentTypeJSON, "{}", time.Now()),
+		target.ID, database.DeliveryStatusDelivered,
+	)
+
+	assert.Contains(t, renderSourceLogsPageWithQuery(
+		t, f.h, f.sess, f.webhook.ID, "?show=failed",
+	), "No event has a failed delivery.")
+	assert.Contains(t, renderSourceLogsPageWithQuery(
+		t, f.h, f.sess, f.webhook.ID, "?show=pending",
+	), "No event has a delivery pending or retrying.")
+}
+
 // TestHandleSourceLogs_OnlyNewestStartsExpanded proves that of the
 // events in the log only the newest starts expanded.
 func TestHandleSourceLogs_OnlyNewestStartsExpanded(t *testing.T) {

internal/handlers/source_management.go

@@ -1110,6 +1110,15 @@ func (h *Handlers) ownedWebhook(
 	return webhook, true
 }
 
+// The event log's show query parameter and its two values: the events
+// with a failed delivery, and those with a delivery still pending or
+// retrying.
+const (
+	showParam   = "show"
+	showFailed  = "failed"
+	showPending = "pending"
+)
+
 // HandleSourceLogs shows the request/response logs for a
 // webhook.
 func (h *Handlers) HandleSourceLogs() http.HandlerFunc {
@@ -1129,17 +1138,36 @@ func (h *Handlers) HandleSourceLogs() http.HandlerFunc {
 			return
 		}
 
+		// Any other value of show lists every event, as no value
+		// does.
+		show := r.URL.Query().Get(showParam)
+
+		statuses := eventLogStatuses(show)
+		if statuses == nil {
+			show = ""
+		}
+
 		evts, total, ok := h.loadEventsWithDeliveries(
-			w, r, webhook, targets,
+			w, r, webhook, targets, statuses,
 		)
 		if !ok {
 			return
 		}
 
+		failed, pending, err := h.countFailedAndPendingEvents(webhook.ID)
+		if err != nil {
+			h.serverError(w, r, "failed to count events", err)
+
+			return
+		}
+
 		data := map[string]any{
-			tmplKeyWebhook: &webhook,
-			"Events":       evts,
-			"TotalEvents":  total,
+			tmplKeyWebhook:  &webhook,
+			"Events":        evts,
+			"TotalEvents":   total,
+			"Show":          show,
+			"FailedEvents":  failed,
+			"PendingEvents": pending,
 		}
 
 		h.renderTemplate(w, r, "source_logs.html", data)
@@ -1201,9 +1229,10 @@ func (h *Handlers) loadTargetMap(
 
 // loadEventsWithDeliveries loads the recentEventLimit newest events
 // and their deliveries from the per-webhook database, and the total
-// number of events stored. Events come back as capped projections
-// rather than database.Event rows: see eventLogColumns for why the
-// cut happens in SQL.
+// number of events stored. Given delivery statuses, both cover only
+// the events with a delivery in one of them. Events come back as
+// capped projections rather than database.Event rows: see
+// eventLogColumns for why the cut happens in SQL.
 //
 // The bool reports whether the load succeeded. It is false
 // once this has answered the request with an error, and the
@@ -1213,6 +1242,7 @@ func (h *Handlers) loadEventsWithDeliveries(
 	r *http.Request,
 	webhook database.Webhook,
 	targetMap map[string]eventLogTarget,
+	statuses []database.DeliveryStatus,
 ) ([]EventLogView, int64, bool) {
 	if !h.dbMgr.DBExists(webhook.ID) {
 		return nil, 0, true
@@ -1227,7 +1257,14 @@ func (h *Handlers) loadEventsWithDeliveries(
 		return nil, 0, false
 	}
 
-	rows, totalEvents := loadEventLogRows(webhookDB, webhook.ID)
+	rows, totalEvents, err := loadEventLogRows(
+		webhookDB, webhook.ID, statuses,
+	)
+	if err != nil {
+		h.serverError(w, r, "failed to load events", err)
+
+		return nil, 0, false
+	}
 
 	result, ok := h.eventLogViews(
 		w, r, webhookDB, webhook.ID, rows, targetMap,
@@ -1321,25 +1358,142 @@ func (h *Handlers) eventLogViews(
 
 // loadEventLogRows reads the event log projection of the
 // recentEventLimit newest events, newest first, and the total number
-// of events stored.
+// of events stored, both narrowed by statuses as eventsWithStatus
+// narrows them.
 func loadEventLogRows(
-	webhookDB *gorm.DB, webhookID string,
-) ([]eventLogRow, int64) {
-	var totalEvents int64
-
-	webhookDB.Model(&database.Event{}).Where(
-		"webhook_id = ?", webhookID,
-	).Count(&totalEvents)
+	webhookDB *gorm.DB,
+	webhookID string,
+	statuses []database.DeliveryStatus,
+) ([]eventLogRow, int64, error) {
+	totalEvents, err := countEventsWithStatus(
+		webhookDB, webhookID, statuses,
+	)
+	if err != nil {
+		return nil, 0, err
+	}
 
 	var rows []eventLogRow
 
-	webhookDB.Model(&database.Event{}).Select(
+	err = eventsWithStatus(webhookDB, webhookID, statuses).Select(
 		eventLogColumns, maxRenderedBodyBytes, maxRenderedBodyBytes,
-	).Where(
-		"webhook_id = ?", webhookID,
-	).Order("created_at DESC").Limit(recentEventLimit).Find(&rows)
+	).Order("created_at DESC").Limit(recentEventLimit).Find(&rows).Error
 
-	return rows, totalEvents
+	return rows, totalEvents, err
+}
+
+// eventLogStatuses returns the delivery statuses the event log's show
+// value lists events by, or nil for one that lists every event.
+func eventLogStatuses(show string) []database.DeliveryStatus {
+	switch show {
+	case showFailed:
+		return []database.DeliveryStatus{database.DeliveryStatusFailed}
+	case showPending:
+		return []database.DeliveryStatus{
+			database.DeliveryStatusPending,
+			database.DeliveryStatusRetrying,
+		}
+	default:
+		return nil
+	}
+}
+
+// eventsWithStatus selects the webhook's events, or, given statuses,
+// the recentEventLimit newest of those with at least one delivery in
+// one of them.
+//
+// Given statuses, its cost follows the matching deliveries. SQLite
+// never reorders a CROSS JOIN, so it reads each join's left side
+// first: the distinct event IDs of the matching deliveries, through
+// idx_deliveries_status; then each of those events by ID, sorted to
+// keep the newest; then the rows of only the events kept, so no other
+// event's body is read. With a plain "id IN (matching deliveries)"
+// condition instead, SQLite, which keeps no statistics on these
+// tables, walks every event newest first.
+func eventsWithStatus(
+	webhookDB *gorm.DB,
+	webhookID string,
+	statuses []database.DeliveryStatus,
+) *gorm.DB {
+	if statuses == nil {
+		return webhookDB.Model(&database.Event{}).Where(
+			"webhook_id = ?", webhookID,
+		)
+	}
+
+	matching := webhookDB.Model(&database.Delivery{}).
+		Distinct("event_id").Where("status IN ?", statuses)
+
+	newest := webhookDB.Table("(?) AS matching", matching).
+		Joins("CROSS JOIN events ON events.id = matching.event_id").
+		Where(
+			"events.webhook_id = ? AND events.deleted_at IS NULL",
+			webhookID,
+		).
+		Order("events.created_at DESC").Limit(recentEventLimit).
+		Select("events.id AS event_id")
+
+	return webhookDB.Table("(?) AS newest", newest).
+		Joins("CROSS JOIN events ON events.id = newest.event_id")
+}
+
+// countEventsWithStatus counts the webhook's events with at least one
+// delivery in one of the statuses, or every event when statuses is
+// nil. Given statuses, it counts the distinct events of the matching
+// deliveries and reads nothing but those deliveries, through
+// idx_deliveries_status, where counting the events would read every
+// event row. That is the same number, because retention deletes an
+// event's deliveries with it.
+func countEventsWithStatus(
+	webhookDB *gorm.DB,
+	webhookID string,
+	statuses []database.DeliveryStatus,
+) (int64, error) {
+	var count int64
+
+	if statuses == nil {
+		err := webhookDB.Model(&database.Event{}).Where(
+			"webhook_id = ?", webhookID,
+		).Count(&count).Error
+
+		return count, err
+	}
+
+	err := webhookDB.Model(&database.Delivery{}).Distinct("event_id").
+		Where("status IN ?", statuses).Count(&count).Error
+
+	return count, err
+}
+
+// countFailedAndPendingEvents returns how many of the webhook's events
+// the event log lists when it shows only those with a failed delivery,
+// and when it shows only those with a delivery pending or retrying.
+func (h *Handlers) countFailedAndPendingEvents(
+	webhookID string,
+) (int64, int64, error) {
+	if !h.dbMgr.DBExists(webhookID) {
+		return 0, 0, nil
+	}
+
+	webhookDB, err := h.dbMgr.GetDB(webhookID)
+	if err != nil {
+		return 0, 0, err
+	}
+
+	failed, err := countEventsWithStatus(
+		webhookDB, webhookID, eventLogStatuses(showFailed),
+	)
+	if err != nil {
+		return 0, 0, err
+	}
+
+	pending, err := countEventsWithStatus(
+		webhookDB, webhookID, eventLogStatuses(showPending),
+	)
+	if err != nil {
+		return 0, 0, err
+	}
+
+	return failed, pending, nil
 }
 
 // resubmitCounts reports, for each of the page's events, how many

internal/handlers/target_paused_test.go

@@ -91,7 +91,8 @@ func TestPausedTarget_ShownUntilBreakerCloses(t *testing.T) {
 	assert.Contains(t, log, "t-http: delivered")
 	assert.Regexp(t, waiting+cooldownEnds, log)
 	assert.Contains(t, log, waiting+backoffEnds)
-	assert.NotContains(t, log, "retrying")
+	// No delivery shows as retrying; the Pending link's title says it.
+	assert.NotRegexp(t, `t-http: retrying|>retrying<`, log)
 
 	page := eventPage(t, h, sess, wh.ID, retrying.ID)
 	assert.Regexp(t, waiting+cooldownEnds, page)