Serve the delivery duration histogram from boot (closes #267)

webhooker_delivery_duration_seconds was absent from /metrics until the first delivery, while every other delivery series is materialised at zero when the collectors are registered. initSeries now materialises the histogram too, for the same four target types, so a scrape of an instance that has delivered nothing shows it with a zero count and sum. The registration test lists it with the other series, and a new route test scrapes /metrics on a freshly built instance and finds it for every target type.

Model: opus-5-5

TODO.md

@@ -40,12 +40,6 @@ duplicate. That is deliberate — the alternative is a silent lost
 delivery — and the README says so under Rationale. It is not a defect
 to re-file.
 
-One caveat on reading a green check: a docs-only commit deliberately
-replays from the layer cache
-(https://git.eeqj.de/sneak/webhooker/issues/119), so a green status on
-such a commit evidences a replay rather than an executed run. A code
-commit invalidates the `COPY` layer and genuinely executes.
-
 # Next Step
 
 Clear the rest of the open 1.0.0 milestone

internal/delivery/engine.go

@@ -14,6 +14,7 @@ import (
 	"go.uber.org/fx"
 	"gorm.io/gorm"
 	"sneak.berlin/go/webhooker/internal/database"
+	"sneak.berlin/go/webhooker/internal/globals"
 	"sneak.berlin/go/webhooker/internal/lifecycle"
 	"sneak.berlin/go/webhooker/internal/logger"
 	"sneak.berlin/go/webhooker/internal/metrics"
@@ -146,6 +147,7 @@ type EngineParams struct {
 
 	DB        *database.Database
 	DBManager *database.WebhookDBManager
+	Globals   *globals.Globals
 	Logger    *logger.Logger
 	SSRFGuard *Guard
 	Metrics   *metrics.Set
@@ -168,6 +170,10 @@ type Engine struct {
 	retryCh    chan Task
 	workers    int
 
+	// version is the running build's version, the one the web UI
+	// footer shows. userAgent puts it on every outbound request.
+	version string
+
 	// mtr is the delivery metric set. Production wires the one
 	// registered on the registry /metrics serves; a test can
 	// substitute a set registered on a registry it holds, so it can
@@ -205,6 +211,7 @@ func New(
 		deliveryCh: make(chan Task, deliveryChannelSize),
 		retryCh:    make(chan Task, retryChannelSize),
 		workers:    defaultWorkers,
+		version:    params.Globals.Version,
 		mtr:        params.Metrics,
 	}
 
@@ -301,6 +308,13 @@ func (e *Engine) ScheduleRetry(
 	})
 }
 
+// userAgent is the User-Agent header of every http and slack
+// delivery request: the program name and the running build's
+// version.
+func (e *Engine) userAgent() string {
+	return "webhooker/" + e.version
+}
+
 // registerHooks wires the engine's start and stop into the fx
 // lifecycle. The start hook's context is deliberately ignored
 // (see start for why the worker pool must not inherit it); the

internal/delivery/engine_test.go

@@ -1247,11 +1247,6 @@ func TestDoHTTPRequest_ForwardsHeaders(t *testing.T) {
 		testContentType,
 		receivedHeaders.Get("Content-Type"),
 	)
-
-	assert.Equal(t,
-		"webhooker/1.0",
-		receivedHeaders.Get("User-Agent"),
-	)
 }
 
 // The event's stored inbound headers carry the same Content-Type the
@@ -1320,6 +1315,7 @@ func TestApplyRequestHeaders_SendsOneContentType(t *testing.T) {
 					ContentType: tc.event,
 				},
 				cfg,
+				"webhooker/dev",
 			)
 
 			assert.Equal(t,

internal/delivery/export_test.go

@@ -83,8 +83,9 @@ func ExportApplyRequestHeaders(
 	req *http.Request,
 	event *database.Event,
 	cfg *HTTPTargetConfig,
+	userAgent string,
 ) []string {
-	return applyRequestHeaders(req, event, cfg)
+	return applyRequestHeaders(req, event, cfg, userAgent)
 }
 
 // ExportTruncate exposes truncate for testing.

internal/delivery/redirect_test.go

@@ -375,6 +375,7 @@ func TestApplyRequestHeaders_ReportsOriginScopedNames(t *testing.T) {
 				"Content-Type":  testContentType,
 			},
 		},
+		"webhooker/dev",
 	)
 
 	assert.Equal(t,

internal/delivery/target_http.go

@@ -442,7 +442,9 @@ func (t *httpTarget) doHTTPRequest(
 		)
 	}
 
-	originScoped := applyRequestHeaders(req, event, cfg)
+	originScoped := applyRequestHeaders(
+		req, event, cfg, t.eng.userAgent(),
+	)
 
 	client := t.clientForRequest(cfg, originScoped)
 
@@ -562,10 +564,13 @@ func isForwardableHeader(name string) bool {
 // Content-Type goes out once: a Content-Type configured on the target
 // wins, otherwise the event's ContentType, otherwise none. The inbound
 // Content-Type in the event's headers is never forwarded.
+//
+// userAgent is set last, over any configured or inbound User-Agent.
 func applyRequestHeaders(
 	req *http.Request,
 	event *database.Event,
 	cfg *HTTPTargetConfig,
+	userAgent string,
 ) []string {
 	if event.ContentType != "" {
 		req.Header.Set(
@@ -580,7 +585,7 @@ func applyRequestHeaders(
 		originScoped[http.CanonicalHeaderKey(k)] = struct{}{}
 	}
 
-	req.Header.Set("User-Agent", "webhooker/1.0")
+	req.Header.Set("User-Agent", userAgent)
 
 	// A Content-Type configured on the target describes the body
 	// being sent rather than the sender. A 307/308 preserves the

internal/delivery/target_slack.go

@@ -136,7 +136,7 @@ func (t *slackTarget) attempt(
 	}
 
 	req.Header.Set("Content-Type", "application/json")
-	req.Header.Set("User-Agent", "webhooker/1.0")
+	req.Header.Set("User-Agent", t.eng.userAgent())
 
 	resp, doErr := executeHTTPRequest(t.client, req)
 	durationMs := time.Since(start).Milliseconds()

internal/delivery/user_agent_test.go

@@ -0,0 +1,91 @@
+package delivery_test
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"net/netip"
+	"testing"
+
+	"github.com/google/uuid"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/fx/fxtest"
+	"sneak.berlin/go/webhooker/internal/database"
+	"sneak.berlin/go/webhooker/internal/delivery"
+	"sneak.berlin/go/webhooker/internal/globals"
+	"sneak.berlin/go/webhooker/internal/logger"
+	"sneak.berlin/go/webhooker/internal/metrics"
+)
+
+// Both the http and the slack target send webhooker/ and the version
+// in Globals, the value the web UI footer shows. A User-Agent
+// configured on the target or carried in by the sender does not
+// replace it.
+func TestUserAgent_IsTheBuildVersion(t *testing.T) {
+	t.Parallel()
+
+	const want = "webhooker/1.2.3-test"
+
+	userAgents := make(chan string, 1)
+
+	ts := httptest.NewServer(http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			userAgents <- r.Header.Get("User-Agent")
+
+			w.WriteHeader(http.StatusOK)
+		},
+	))
+	defer ts.Close()
+
+	g := &globals.Globals{Version: "1.2.3-test"}
+	lc := fxtest.NewLifecycle(t)
+
+	log, err := logger.New(lc, logger.LoggerParams{Globals: g})
+	require.NoError(t, err)
+
+	e := delivery.New(lc, delivery.EngineParams{
+		Globals: g,
+		Logger:  log,
+		// httptest listens on loopback, which the default guard
+		// refuses.
+		SSRFGuard: delivery.NewTestGuard(
+			netip.MustParsePrefix("127.0.0.0/8"),
+		),
+		Metrics: metrics.New(prometheus.NewRegistry()),
+	})
+
+	statusCode, _, _, err := e.ExportDoHTTPRequest(
+		context.Background(),
+		&delivery.HTTPTargetConfig{
+			URL:     ts.URL,
+			Headers: map[string]string{"User-Agent": "configured/1"},
+		},
+		&database.Event{Headers: `{"User-Agent":["curl/8"]}`},
+	)
+	require.NoError(t, err)
+	require.Equal(t, http.StatusOK, statusCode)
+	require.Len(t, userAgents, 1, "the http target sent no request")
+	assert.Equal(t, want, <-userAgents, "http target")
+
+	db := testWebhookDB(t)
+	targetID := uuid.New().String()
+
+	slackCfg, err := json.Marshal(
+		delivery.SlackTargetConfig{WebhookURL: ts.URL},
+	)
+	require.NoError(t, err)
+
+	event := seedEvent(t, db, `{"action":"test"}`)
+	dlv := seedDelivery(
+		t, db, event.ID, targetID, database.DeliveryStatusPending,
+	)
+
+	e.ExportDeliverSlack(context.Background(), db, buildSlackDelivery(
+		dlv, event, targetID, "test-slack", string(slackCfg),
+	))
+	require.Len(t, userAgents, 1, "the slack target sent no request")
+	assert.Equal(t, want, <-userAgents, "slack target")
+}

internal/handlers/auth.go

@@ -333,7 +333,9 @@ func (h *Handlers) HandleLogout() http.HandlerFunc {
 			)
 		}
 
-		// Redirect to login page
-		http.Redirect(w, r, "/pages/login", http.StatusSeeOther)
+		http.Redirect(
+			w, r, withNotice("/pages/login", signedOut),
+			http.StatusSeeOther,
+		)
 	}
 }

internal/handlers/delivery_replay.go

@@ -11,72 +11,37 @@ import (
 	"sneak.berlin/go/webhooker/internal/delivery"
 )
 
-// replayOutcomeParam is the query parameter the replay POST redirects
-// with and the event log page reads its banner from.
-const replayOutcomeParam = "replay"
-
-// replayOutcomeCode is the outcome of a replay POST. The redirect
-// carries one of these fixed codes rather than a message, so nothing a
-// client submits can reach the rendered page through it.
-type replayOutcomeCode string
-
+// The outcomes of a replay POST, as the notice codes its redirect
+// carries. noticeFor holds the line each one shows.
 const (
 	// replayQueued reports that a new delivery was created and handed
 	// to the delivery engine.
-	replayQueued replayOutcomeCode = "queued"
+	replayQueued noticeCode = "replay-queued"
 
 	// replayTargetDeleted reports a target that once existed and has
 	// since been deleted. Deletes are soft and deliveries carry no
 	// foreign key to the target row, so the history survives its
 	// target and this is the ordinary case for an old event.
-	replayTargetDeleted replayOutcomeCode = "target-deleted"
+	replayTargetDeleted noticeCode = "replay-target-deleted"
 
 	// replayTargetMissing reports a target id that names no row at
 	// all, deleted or otherwise.
-	replayTargetMissing replayOutcomeCode = "target-missing"
+	replayTargetMissing noticeCode = "replay-target-missing"
 
 	// replayTargetInactive reports a target the operator has
 	// deactivated. A deactivated target receives no new deliveries, so
 	// a replay to it would be a delivery they switched off.
-	replayTargetInactive replayOutcomeCode = "target-inactive"
+	replayTargetInactive noticeCode = "replay-target-inactive"
 
 	// replayNotTerminal reports a delivery the engine has not finished
 	// with.
-	replayNotTerminal replayOutcomeCode = "not-terminal"
+	replayNotTerminal noticeCode = "replay-not-terminal"
 
 	// replayInFlight reports that an earlier replay of this event to
 	// this target is still running.
-	replayInFlight replayOutcomeCode = "in-flight"
+	replayInFlight noticeCode = "replay-in-flight"
 )
 
-// replayOutcome returns the banner the event log page shows for an
-// outcome code, and whether the replay was queued. An unrecognised
-// code yields no banner.
-func replayOutcome(code string) (string, bool) {
-	switch replayOutcomeCode(code) {
-	case replayQueued:
-		return "Replay queued: a new delivery was created against " +
-			"the target's current configuration.", true
-	case replayTargetDeleted:
-		return "Not replayed: the target this delivery was for has " +
-			"been deleted. Recreate the target, then replay.", false
-	case replayTargetMissing:
-		return "Not replayed: the target this delivery was for no " +
-			"longer exists.", false
-	case replayTargetInactive:
-		return "Not replayed: the target this delivery was for is " +
-			"deactivated. Activate it, then replay.", false
-	case replayNotTerminal:
-		return "Not replayed: this delivery has not finished yet.",
-			false
-	case replayInFlight:
-		return "Not replayed: a delivery of this event to this " +
-			"target is already in flight.", false
-	default:
-		return "", false
-	}
-}
-
 // HandleDeliveryReplay re-sends a finished delivery's event to its
 // target.
 //
@@ -140,14 +105,14 @@ func (h *Handlers) replayDelivery(
 	}
 
 	if !original.Status.Terminal() {
-		h.finishReplay(w, r, webhook, replayNotTerminal)
+		redirectToEventLog(w, r, webhook, replayNotTerminal)
 
 		return
 	}
 
 	target, code := h.replayTarget(webhook.ID, original.TargetID)
 	if target == nil {
-		h.finishReplay(w, r, webhook, code)
+		redirectToEventLog(w, r, webhook, code)
 
 		return
 	}
@@ -200,7 +165,7 @@ func (h *Handlers) queueReplay(
 	}
 
 	if inFlight > 0 {
-		h.finishReplay(w, r, webhook, replayInFlight)
+		redirectToEventLog(w, r, webhook, replayInFlight)
 
 		return
 	}
@@ -238,7 +203,7 @@ func (h *Handlers) queueReplay(
 		"delivery_id", task.DeliveryID,
 	)
 
-	h.finishReplay(w, r, webhook, replayQueued)
+	redirectToEventLog(w, r, webhook, replayQueued)
 }
 
 // replayTarget loads the delivery's target as it stands now.
@@ -251,7 +216,7 @@ func (h *Handlers) queueReplay(
 // with the returned code saying why.
 func (h *Handlers) replayTarget(
 	webhookID, targetID string,
-) (*database.Target, replayOutcomeCode) {
+) (*database.Target, noticeCode) {
 	var target database.Target
 
 	err := h.db.DB().Unscoped().Where(
@@ -361,17 +326,16 @@ func replayBody(body string) *string {
 	return &body
 }
 
-// finishReplay redirects back to the event log the replay was
-// triggered from, carrying the outcome code the page turns into a
-// banner and the page number the form submitted.
-func (h *Handlers) finishReplay(
+// redirectToEventLog redirects a replay or resubmit back to the event
+// log it was triggered from, carrying the outcome as its notice and
+// the page number the form submitted.
+func redirectToEventLog(
 	w http.ResponseWriter,
 	r *http.Request,
 	webhook database.Webhook,
-	code replayOutcomeCode,
+	code noticeCode,
 ) {
-	dest := "/hook/" + webhook.ID + "/events?" +
-		replayOutcomeParam + "=" + string(code)
+	dest := withNotice("/hook/"+webhook.ID+"/events", code)
 
 	// The page is read from the form rather than the query string:
 	// this is a POST, and its query string is what logs and Referer

internal/handlers/delivery_replay_test.go

@@ -212,7 +212,7 @@ func TestHandleDeliveryReplay_AppendsDeliveryAndLeavesOriginal(
 	require.Equal(t, http.StatusSeeOther, w.Code)
 	assert.Equal(
 		t,
-		"/hook/"+wh.ID+"/events?replay=queued",
+		"/hook/"+wh.ID+"/events?notice=replay-queued",
 		w.Header().Get("Location"),
 	)
 
@@ -362,7 +362,7 @@ func TestHandleDeliveryReplay_RefusesDeletedTarget(t *testing.T) {
 	require.Equal(t, http.StatusSeeOther, w.Code)
 	assert.Equal(
 		t,
-		"/hook/"+wh.ID+"/events?replay=target-deleted",
+		"/hook/"+wh.ID+"/events?notice=replay-target-deleted",
 		w.Header().Get("Location"),
 	)
 
@@ -390,7 +390,7 @@ func TestHandleDeliveryReplay_RefusesDeletedTarget(t *testing.T) {
 	require.Equal(t, http.StatusSeeOther, missing.Code)
 	assert.Equal(
 		t,
-		"/hook/"+wh.ID+"/events?replay=target-missing",
+		"/hook/"+wh.ID+"/events?notice=replay-target-missing",
 		missing.Header().Get("Location"),
 	)
 }
@@ -431,7 +431,7 @@ func TestHandleDeliveryReplay_RefusesWhileEarlierReplayInFlight(
 	require.Equal(t, http.StatusSeeOther, first.Code)
 	require.Equal(
 		t,
-		"/hook/"+wh.ID+"/events?replay=queued",
+		"/hook/"+wh.ID+"/events?notice=replay-queued",
 		first.Header().Get("Location"),
 	)
 
@@ -439,7 +439,7 @@ func TestHandleDeliveryReplay_RefusesWhileEarlierReplayInFlight(
 	require.Equal(t, http.StatusSeeOther, second.Code)
 	assert.Equal(
 		t,
-		"/hook/"+wh.ID+"/events?replay=in-flight",
+		"/hook/"+wh.ID+"/events?notice=replay-in-flight",
 		second.Header().Get("Location"),
 	)
 
@@ -465,7 +465,7 @@ func TestHandleDeliveryReplay_RefusesWhileEarlierReplayInFlight(
 	require.Equal(t, http.StatusSeeOther, pending.Code)
 	assert.Equal(
 		t,
-		"/hook/"+wh.ID+"/events?replay=not-terminal",
+		"/hook/"+wh.ID+"/events?notice=replay-not-terminal",
 		pending.Header().Get("Location"),
 	)
 }
@@ -509,7 +509,7 @@ func TestHandleSourceLogs_RendersReplayControlAndBanner(t *testing.T) {
 	assert.Contains(t, body, ">Replay<")
 
 	refused := renderSourceLogsPageWithQuery(
-		t, h, sess, wh.ID, "?replay=target-deleted",
+		t, h, sess, wh.ID, "?notice=replay-target-deleted",
 	)
 
 	assert.Contains(t, refused, "alert-error")
@@ -517,7 +517,7 @@ func TestHandleSourceLogs_RendersReplayControlAndBanner(t *testing.T) {
 
 	// An outcome code nobody issued renders no banner at all.
 	unknown := renderSourceLogsPageWithQuery(
-		t, h, sess, wh.ID, "?replay=made-up",
+		t, h, sess, wh.ID, "?notice=made-up",
 	)
 
 	assert.NotContains(t, unknown, "alert-error")

internal/handlers/event_resubmit.go

@@ -3,7 +3,6 @@ package handlers
 import (
 	"errors"
 	"net/http"
-	"strconv"
 
 	"github.com/go-chi/chi"
 	"github.com/google/uuid"
@@ -11,43 +10,19 @@ import (
 	"sneak.berlin/go/webhooker/internal/database"
 )
 
-// resubmitOutcomeParam is the query parameter the resubmit POST
-// redirects with and the event log page reads its banner from.
-const resubmitOutcomeParam = "resubmit"
-
-// resubmitOutcomeCode is the outcome of a resubmit POST. The redirect
-// carries one of these fixed codes rather than a message, so nothing a
-// client submits can reach the rendered page through it.
-type resubmitOutcomeCode string
-
+// The outcomes of a resubmit POST, as the notice codes its redirect
+// carries. noticeFor holds the line each one shows.
 const (
 	// resubmitQueued reports that a new event was stored and its
 	// deliveries handed to the delivery engine.
-	resubmitQueued resubmitOutcomeCode = "queued"
+	resubmitQueued noticeCode = "resubmit-queued"
 
 	// resubmitNoTargets reports a source with no active targets. The
 	// new event is stored either way, exactly as a received event
 	// with no targets is.
-	resubmitNoTargets resubmitOutcomeCode = "no-targets"
+	resubmitNoTargets noticeCode = "resubmit-no-targets"
 )
 
-// resubmitOutcome returns the banner the event log page shows for an
-// outcome code, and whether the resubmit was queued. An unrecognised
-// code yields no banner.
-func resubmitOutcome(code string) (string, bool) {
-	switch resubmitOutcomeCode(code) {
-	case resubmitQueued:
-		return "Resubmitted: a new event was created from the stored " +
-			"one and queued to every active target.", true
-	case resubmitNoTargets:
-		return "Resubmitted: a new event was created, but this " +
-				"source has no active targets, so nothing was queued.",
-			true
-	default:
-		return "", false
-	}
-}
-
 // resubmitSource is the stored event a resubmit copies. Its body is
 // read as bytes rather than as a string so the copy is byte-identical
 // to what was received, whatever the payload's encoding.
@@ -245,29 +220,5 @@ func (h *Handlers) queueResubmit(
 		code = resubmitNoTargets
 	}
 
-	h.finishResubmit(w, r, webhook, code)
-}
-
-// finishResubmit redirects back to the event log the resubmit was
-// triggered from, carrying the outcome code the page turns into a
-// banner and the page number the form submitted.
-func (h *Handlers) finishResubmit(
-	w http.ResponseWriter,
-	r *http.Request,
-	webhook database.Webhook,
-	code resubmitOutcomeCode,
-) {
-	dest := "/hook/" + webhook.ID + "/events?" +
-		resubmitOutcomeParam + "=" + string(code)
-
-	// The page is read from the form rather than the query string:
-	// this is a POST, and its query string is what logs and Referer
-	// headers record.
-	if page := pageOrFirst(
-		r.PostFormValue("page"),
-	); page > 1 {
-		dest += "&page=" + strconv.Itoa(page)
-	}
-
-	http.Redirect(w, r, dest, http.StatusSeeOther)
+	redirectToEventLog(w, r, webhook, code)
 }

internal/handlers/event_resubmit_test.go

@@ -154,7 +154,7 @@ func TestHandleEventResubmit_DeliversToTargetCreatedAfterTheEvent(
 	require.Equal(t, http.StatusSeeOther, w.Code)
 	assert.Equal(
 		t,
-		"/hook/"+wh.ID+"/events?resubmit=queued",
+		"/hook/"+wh.ID+"/events?notice=resubmit-queued",
 		w.Header().Get("Location"),
 	)
 
@@ -282,7 +282,7 @@ func TestHandleEventResubmit_IsRepeatable(t *testing.T) {
 		require.Equal(t, http.StatusSeeOther, w.Code)
 		assert.Equal(
 			t,
-			"/hook/"+wh.ID+"/events?resubmit=queued",
+			"/hook/"+wh.ID+"/events?notice=resubmit-queued",
 			w.Header().Get("Location"),
 			"a resubmit must not be refused while an earlier "+
 				"one is in flight",
@@ -436,7 +436,7 @@ func TestHandleEventResubmit_SkipsInactiveTarget(t *testing.T) {
 	require.Equal(t, http.StatusSeeOther, w.Code)
 	assert.Equal(
 		t,
-		"/hook/"+wh.ID+"/events?resubmit=queued",
+		"/hook/"+wh.ID+"/events?notice=resubmit-queued",
 		w.Header().Get("Location"),
 		"an inactive target is skipped, not an error",
 	)
@@ -482,7 +482,7 @@ func TestHandleEventResubmit_NoActiveTargetsStillStoresEvent(
 	require.Equal(t, http.StatusSeeOther, w.Code)
 	assert.Equal(
 		t,
-		"/hook/"+wh.ID+"/events?resubmit=no-targets",
+		"/hook/"+wh.ID+"/events?notice=resubmit-no-targets",
 		w.Header().Get("Location"),
 	)
 

internal/handlers/handlers.go

@@ -97,10 +97,10 @@ 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, and with any further files
-// the page includes. The page file must be listed first so that its
-// root action ({{template "base" .}}) becomes the template set's entry
-// point.
+// base, htmlheader, navbar and notice templates, and with any further
+// files the page includes. The page file must be listed first so that
+// its root action ({{template "base" .}}) becomes the template set's
+// entry point.
 func parsePageTemplate(
 	pageFile string, included ...string,
 ) *template.Template {
@@ -109,6 +109,7 @@ func parsePageTemplate(
 		"base.html",
 		"htmlheader.html",
 		"navbar.html",
+		"notice.html",
 	}, included...)
 
 	return template.Must(
@@ -209,11 +210,13 @@ func (s *Handlers) renderError(
 	// served outside the routes where NoCache runs.
 	w.Header().Set("Cache-Control", "no-store")
 
+	// No notice: one would say an action worked above a page saying
+	// the request failed.
 	data := s.pageData(r, map[string]any{
 		"Status":     status,
 		"StatusText": http.StatusText(status),
 		"Message":    errorPageText(status),
-	})
+	}, nil)
 
 	var buf bytes.Buffer
 
@@ -267,6 +270,7 @@ type templateDataWrapper struct {
 	User      *UserInfo
 	CSRFToken string
 	Version   string
+	Notice    *notice
 	Data      any
 }
 
@@ -311,12 +315,15 @@ func (s *Handlers) renderTemplate(
 		return
 	}
 
-	s.executeTemplate(w, r, tmpl, s.pageData(r, data))
+	s.executeTemplate(w, r, tmpl, s.pageData(r, data, noticeFor(r)))
 }
 
 // pageData adds the fields the shared layout renders to a page's own
-// data.
-func (s *Handlers) pageData(r *http.Request, data any) any {
+// data. The layout shows the notice, when there is one, above the
+// page.
+func (s *Handlers) pageData(
+	r *http.Request, data any, pageNotice *notice,
+) any {
 	userInfo := s.getUserInfo(r)
 	csrfToken := middleware.CSRFToken(r)
 
@@ -330,6 +337,7 @@ func (s *Handlers) pageData(r *http.Request, data any) any {
 		m["User"] = userInfo
 		m["CSRFToken"] = csrfToken
 		m["Version"] = version
+		m["Notice"] = pageNotice
 
 		return m
 	}
@@ -338,6 +346,7 @@ func (s *Handlers) pageData(r *http.Request, data any) any {
 		User:      userInfo,
 		CSRFToken: csrfToken,
 		Version:   version,
+		Notice:    pageNotice,
 		Data:      data,
 	}
 }

internal/handlers/notice.go

@@ -0,0 +1,109 @@
+package handlers
+
+import "net/http"
+
+// noticeParam is the query parameter an action's redirect carries its
+// notice code in.
+const noticeParam = "notice"
+
+// noticeCode names one of the fixed lines noticeFor knows. An action
+// redirects with the code rather than the line, so nothing a client
+// puts in the URL reaches the page: a code noticeFor does not know
+// shows nothing.
+type noticeCode string
+
+// The codes of the actions on the webhook pages and of signing out.
+// Replay's codes, with the reasons a replay can be refused, and
+// resubmit's codes are defined beside those actions.
+const (
+	webhookCreated        noticeCode = "webhook-created"
+	webhookSaved          noticeCode = "webhook-saved"
+	webhookDeleted        noticeCode = "webhook-deleted"
+	entrypointAdded       noticeCode = "entrypoint-added"
+	entrypointDeleted     noticeCode = "entrypoint-deleted"
+	entrypointActivated   noticeCode = "entrypoint-activated"
+	entrypointDeactivated noticeCode = "entrypoint-deactivated"
+	targetAdded           noticeCode = "target-added"
+	targetSaved           noticeCode = "target-saved"
+	targetDeleted         noticeCode = "target-deleted"
+	targetActivated       noticeCode = "target-activated"
+	targetDeactivated     noticeCode = "target-deactivated"
+	signedOut             noticeCode = "signed-out"
+)
+
+// notice is the line templates/notice.html shows above a page to say
+// what an action did.
+type notice struct {
+	Text string
+
+	// Failed shows the line as an error: the action was refused.
+	Failed bool
+}
+
+// noticeFor returns the notice the request's URL names, or nil when it
+// names none or an unknown code.
+func noticeFor(r *http.Request) *notice {
+	n, ok := map[noticeCode]notice{
+		webhookCreated:        {Text: "Webhook created."},
+		webhookSaved:          {Text: "Webhook saved."},
+		webhookDeleted:        {Text: "Webhook deleted."},
+		entrypointAdded:       {Text: "Entrypoint added."},
+		entrypointDeleted:     {Text: "Entrypoint deleted."},
+		entrypointActivated:   {Text: "Entrypoint activated."},
+		entrypointDeactivated: {Text: "Entrypoint deactivated."},
+		targetAdded:           {Text: "Target added."},
+		targetSaved:           {Text: "Target saved."},
+		targetDeleted:         {Text: "Target deleted."},
+		targetActivated:       {Text: "Target activated."},
+		targetDeactivated:     {Text: "Target deactivated."},
+		signedOut:             {Text: "Signed out."},
+
+		replayQueued: {
+			Text: "Replay queued: a new delivery was created " +
+				"against the target's current configuration.",
+		},
+		replayTargetDeleted: {
+			Text: "Not replayed: the target this delivery was for " +
+				"has been deleted. Recreate the target, then replay.",
+			Failed: true,
+		},
+		replayTargetMissing: {
+			Text: "Not replayed: the target this delivery was for " +
+				"no longer exists.",
+			Failed: true,
+		},
+		replayTargetInactive: {
+			Text: "Not replayed: the target this delivery was for " +
+				"is deactivated. Activate it, then replay.",
+			Failed: true,
+		},
+		replayNotTerminal: {
+			Text:   "Not replayed: this delivery has not finished yet.",
+			Failed: true,
+		},
+		replayInFlight: {
+			Text: "Not replayed: a delivery of this event to this " +
+				"target is already in flight.",
+			Failed: true,
+		},
+
+		resubmitQueued: {
+			Text: "Resubmitted: a new event was created from the " +
+				"stored one and queued to every active target.",
+		},
+		resubmitNoTargets: {
+			Text: "Resubmitted: a new event was created, but this " +
+				"source has no active targets, so nothing was queued.",
+		},
+	}[noticeCode(r.URL.Query().Get(noticeParam))]
+	if !ok {
+		return nil
+	}
+
+	return &n
+}
+
+// withNotice returns path with code added as its notice.
+func withNotice(path string, code noticeCode) string {
+	return path + "?" + noticeParam + "=" + string(code)
+}

internal/handlers/source_delete_test.go

@@ -411,7 +411,9 @@ func TestHandleSourceDelete_RemovesConfigAndEventDatabase(
 	h.HandleSourceDelete().ServeHTTP(w, req)
 
 	require.Equal(t, http.StatusSeeOther, w.Code)
-	assert.Equal(t, "/hooks", w.Header().Get("Location"))
+	assert.Equal(
+		t, "/hooks?notice=webhook-deleted", w.Header().Get("Location"),
+	)
 
 	assert.Equal(
 		t, int64(0),

internal/handlers/source_detail_test.go

@@ -241,3 +241,37 @@ func TestHandleSourceDetail_RendersNamedTargetFields(
 	assert.Contains(t, body, "(unavailable)")
 	assert.NotContains(t, body, "beak")
 }
+
+// TestHandleSourceDetail_FitsWideAndNarrowWindows pins the webhook
+// page's maximum width at 108rem (1728 px), half again the 72rem of
+// max-w-6xl that the webhook list and the event log use, so an
+// entrypoint URL fits on one line in a 1920-pixel window; and the
+// wrapping of its title row, so the buttons beside the title do not
+// push a phone-width window into scrolling sideways.
+func TestHandleSourceDetail_FitsWideAndNarrowWindows(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)
+
+	wh := seedWebhook(t, db)
+
+	body := renderSourceDetailPage(t, h, sess, wh.ID)
+
+	assert.Contains(
+		t, body,
+		`<div class="mx-auto px-6 py-8" style="max-width: 108rem"`,
+	)
+	assert.Contains(
+		t, body,
+		`<div class="flex flex-wrap justify-between items-center gap-2 mt-2">`,
+	)
+}

internal/handlers/source_management.go

@@ -322,7 +322,8 @@ func (h *Handlers) createWebhookWithEntrypoint(
 	)
 
 	http.Redirect(
-		w, r, "/hook/"+webhook.ID, http.StatusSeeOther,
+		w, r, withNotice("/hook/"+webhook.ID, webhookCreated),
+		http.StatusSeeOther,
 	)
 }
 
@@ -579,7 +580,8 @@ func (h *Handlers) applyWebhookEdit(
 	}
 
 	http.Redirect(
-		w, r, "/hook/"+webhook.ID, http.StatusSeeOther,
+		w, r, withNotice("/hook/"+webhook.ID, webhookSaved),
+		http.StatusSeeOther,
 	)
 }
 
@@ -662,7 +664,9 @@ func (h *Handlers) deleteWebhookResources(
 		return
 	}
 
-	http.Redirect(w, r, "/hooks", http.StatusSeeOther)
+	http.Redirect(
+		w, r, withNotice("/hooks", webhookDeleted), http.StatusSeeOther,
+	)
 }
 
 // commitWebhookDeletion soft-deletes a webhook's entrypoints,
@@ -841,31 +845,16 @@ func (h *Handlers) HandleSourceLogs() http.HandlerFunc {
 			totalPages++
 		}
 
-		// The banner a replay or resubmit POST redirected back
-		// with. The message comes from a fixed set keyed by the
-		// outcome code, never from the query string itself.
-		replayMsg, replayOK := replayOutcome(
-			r.URL.Query().Get(replayOutcomeParam),
-		)
-
-		resubmitMsg, resubmitOK := resubmitOutcome(
-			r.URL.Query().Get(resubmitOutcomeParam),
-		)
-
 		data := map[string]any{
-			tmplKeyWebhook:    &webhook,
-			"Events":          evts,
-			"ReplayMessage":   replayMsg,
-			"ReplayQueued":    replayOK,
-			"ResubmitMessage": resubmitMsg,
-			"ResubmitQueued":  resubmitOK,
-			"Page":            page,
-			"TotalPages":      totalPages,
-			"TotalEvents":     total,
-			"HasPrev":         page > 1,
-			"HasNext":         page < totalPages,
-			"PrevPage":        page - 1,
-			"NextPage":        page + 1,
+			tmplKeyWebhook: &webhook,
+			"Events":       evts,
+			"Page":         page,
+			"TotalPages":   totalPages,
+			"TotalEvents":  total,
+			"HasPrev":      page > 1,
+			"HasNext":      page < totalPages,
+			"PrevPage":     page - 1,
+			"NextPage":     page + 1,
 		}
 
 		h.renderTemplate(w, r, "source_logs.html", data)
@@ -1254,7 +1243,8 @@ func (h *Handlers) HandleEntrypointCreate() http.HandlerFunc {
 		}
 
 		http.Redirect(
-			w, r, "/hook/"+webhook.ID, http.StatusSeeOther,
+			w, r, withNotice("/hook/"+webhook.ID, entrypointAdded),
+			http.StatusSeeOther,
 		)
 	}
 }
@@ -1365,7 +1355,8 @@ func (h *Handlers) processTargetCreate(
 	}
 
 	http.Redirect(
-		w, r, "/hook/"+webhook.ID, http.StatusSeeOther,
+		w, r, withNotice("/hook/"+webhook.ID, targetAdded),
+		http.StatusSeeOther,
 	)
 }
 
@@ -1643,6 +1634,7 @@ func (h *Handlers) HandleEntrypointDelete() http.HandlerFunc {
 		"entrypointID", &database.Entrypoint{},
 		"failed to delete entrypoint",
 		nil,
+		entrypointDeleted,
 	)
 }
 
@@ -1655,18 +1647,21 @@ func (h *Handlers) HandleTargetDelete() http.HandlerFunc {
 		"targetID", &database.Target{},
 		"failed to delete target",
 		h.evictArchiveWriterIfUnused,
+		targetDeleted,
 	)
 }
 
 // deleteChildResource returns a handler that deletes a child
 // resource (entrypoint or target) belonging to a webhook. The
 // optional afterDelete hook runs with the webhook's id once the
-// delete has succeeded, before the redirect.
+// delete has succeeded, before the redirect, which carries done as
+// its notice.
 func (h *Handlers) deleteChildResource(
 	idParam string,
 	model any,
 	errMsg string,
 	afterDelete func(webhookID string),
+	done noticeCode,
 ) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		userID, ok := h.getUserID(r)
@@ -1708,7 +1703,7 @@ func (h *Handlers) deleteChildResource(
 
 		http.Redirect(
 			w, r,
-			"/hook/"+webhook.ID,
+			withNotice("/hook/"+webhook.ID, done),
 			http.StatusSeeOther,
 		)
 	}
@@ -1719,7 +1714,7 @@ func (h *Handlers) deleteChildResource(
 func (h *Handlers) HandleEntrypointToggle() http.HandlerFunc {
 	return h.toggleChildResource(
 		"entrypointID",
-		func(webhookID, childID string) error {
+		func(webhookID, childID string) (bool, error) {
 			var ep database.Entrypoint
 
 			err := h.db.DB().Where(
@@ -1727,14 +1722,15 @@ func (h *Handlers) HandleEntrypointToggle() http.HandlerFunc {
 				childID, webhookID,
 			).First(&ep).Error
 			if err != nil {
-				return err
+				return false, err
 			}
 
 			ep.Active = !ep.Active
 
-			return h.db.DB().Save(&ep).Error
+			return ep.Active, h.db.DB().Save(&ep).Error
 		},
 		"failed to toggle entrypoint",
+		entrypointActivated, entrypointDeactivated,
 	)
 }
 
@@ -1742,7 +1738,7 @@ func (h *Handlers) HandleEntrypointToggle() http.HandlerFunc {
 func (h *Handlers) HandleTargetToggle() http.HandlerFunc {
 	return h.toggleChildResource(
 		"targetID",
-		func(webhookID, childID string) error {
+		func(webhookID, childID string) (bool, error) {
 			var tgt database.Target
 
 			err := h.db.DB().Where(
@@ -1750,23 +1746,27 @@ func (h *Handlers) HandleTargetToggle() http.HandlerFunc {
 				childID, webhookID,
 			).First(&tgt).Error
 			if err != nil {
-				return err
+				return false, err
 			}
 
 			tgt.Active = !tgt.Active
 
-			return h.db.DB().Save(&tgt).Error
+			return tgt.Active, h.db.DB().Save(&tgt).Error
 		},
 		"failed to toggle target",
+		targetActivated, targetDeactivated,
 	)
 }
 
 // toggleChildResource returns a handler that toggles the active
-// state of a child resource belonging to a webhook.
+// state of a child resource belonging to a webhook. toggleFn returns
+// the new state, and the redirect carries activated or deactivated as
+// its notice to match.
 func (h *Handlers) toggleChildResource(
 	idParam string,
-	toggleFn func(webhookID, childID string) error,
+	toggleFn func(webhookID, childID string) (bool, error),
 	errMsg string,
+	activated, deactivated noticeCode,
 ) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		userID, ok := h.getUserID(r)
@@ -1792,16 +1792,21 @@ func (h *Handlers) toggleChildResource(
 			return
 		}
 
-		err = toggleFn(webhook.ID, childID)
+		active, err := toggleFn(webhook.ID, childID)
 		if err != nil {
 			h.serverError(w, r, errMsg, err)
 
 			return
 		}
 
+		done := deactivated
+		if active {
+			done = activated
+		}
+
 		http.Redirect(
 			w, r,
-			"/hook/"+webhook.ID,
+			withNotice("/hook/"+webhook.ID, done),
 			http.StatusSeeOther,
 		)
 	}

internal/handlers/target_edit.go

@@ -161,7 +161,8 @@ func (h *Handlers) applyTargetEdit(
 	}
 
 	http.Redirect(
-		w, r, "/hook/"+webhook.ID, http.StatusSeeOther,
+		w, r, withNotice("/hook/"+webhook.ID, targetSaved),
+		http.StatusSeeOther,
 	)
 }
 

internal/metrics/metrics.go

@@ -384,6 +384,7 @@ func (s *Set) initSeries() {
 		s.deliveriesFailed.WithLabelValues(label)
 		s.deliveryRetries.WithLabelValues(label)
 		s.deliveryReplays.WithLabelValues(label)
+		s.deliveryDuration.WithLabelValues(label)
 		s.deliveriesPending.WithLabelValues(label)
 		s.deliveriesRetrying.WithLabelValues(label)
 		s.circuitBreakersOpen.WithLabelValues(label)

internal/metrics/metrics_test.go

@@ -167,6 +167,7 @@ func TestKnownSeriesExistBeforeAnyDelivery(t *testing.T) {
 		"webhooker_deliveries_succeeded_total",
 		"webhooker_deliveries_failed_total",
 		"webhooker_delivery_retries_total",
+		"webhooker_delivery_duration_seconds",
 		"webhooker_circuit_breakers_open",
 	} {
 		assert.ElementsMatch(t,

internal/server/error_page_test.go

@@ -83,6 +83,22 @@ func TestErrorPage_DeletedTarget(t *testing.T) {
 	assertErrorPage(t, w, http.StatusNotFound, backToWebhooks)
 }
 
+// TestErrorPage_ShowsNoNotice pins that a notice code in the URL of a
+// page that fails is not shown above the error.
+func TestErrorPage_ShowsNoNotice(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+
+	userID, _ := env.seedUser(t, "owner", "somepassword")
+	cookies := env.authCookies(t, userID, "owner")
+
+	w := env.get("/hook/no-such-webhook?notice=webhook-saved", cookies)
+
+	assertErrorPage(t, w, http.StatusNotFound, backToWebhooks)
+	assert.NotContains(t, w.Body.String(), "Webhook saved.")
+}
+
 func TestErrorPage_UnknownPath(t *testing.T) {
 	t.Parallel()
 

internal/server/routes_test.go

@@ -263,6 +263,24 @@ func (e *testEnv) urlFrom(
 	return html.UnescapeString(match[1])
 }
 
+// requireNotice requires w to redirect to dest carrying the notice
+// code, then renders that page and requires it to show text.
+func (e *testEnv) requireNotice(
+	t *testing.T,
+	w *httptest.ResponseRecorder,
+	dest, code, text string,
+	cookies []*http.Cookie,
+) {
+	t.Helper()
+
+	require.Equal(t, http.StatusSeeOther, w.Code)
+	require.Equal(t, dest+"?notice="+code, w.Header().Get("Location"))
+
+	page := e.get(w.Header().Get("Location"), cookies)
+	require.Equal(t, http.StatusOK, page.Code)
+	assert.Contains(t, page.Body.String(), text)
+}
+
 // authCookies forges an authenticated session for the given user.
 func (e *testEnv) authCookies(
 	t *testing.T,
@@ -741,6 +759,31 @@ func TestPagesLogin_ReturnsToTheRequestedPage(t *testing.T) {
 	assert.Equal(t, asked, w.Header().Get("Location"))
 }
 
+// TestPagesLogout_SaysSignedOut signs out with the navbar's form and
+// lands on the sign-in page, which says so.
+func TestPagesLogout_SaysSignedOut(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+
+	userID, _ := env.seedUser(t, "leaver", "somepassword")
+	token, cookies := env.csrfFrom(
+		t, "/hooks", env.authCookies(t, userID, "leaver"),
+	)
+
+	form := url.Values{}
+	form.Set("csrf_token", token)
+
+	w := env.post(
+		env.urlFrom(t, "/hooks", `action="(/pages/logout)"`, cookies),
+		form, cookies,
+	)
+
+	// The sign-in page is requested without the session cookie, which
+	// the logout told the browser to delete.
+	env.requireNotice(t, w, "/pages/login", "signed-out", "Signed out.", nil)
+}
+
 // --- /user/{username} group ---
 
 // TestPasswordChange_OversizeBody_RejectedAndPasswordUnchanged
@@ -858,9 +901,9 @@ func TestHooks_ListAndNewWebhookForm(t *testing.T) {
 	require.NoError(t,
 		env.db.DB().Where("name = ?", "created").First(&created).Error,
 	)
-	assert.Equal(
-		t, "/hook/"+created.ID, w.Header().Get("Location"),
-		"creating a webhook should redirect to its page",
+	env.requireNotice(
+		t, w, "/hook/"+created.ID, "webhook-created", "Webhook created.",
+		cookies,
 	)
 }
 
@@ -891,8 +934,7 @@ func TestHook_EditFormAndDelete(t *testing.T) {
 		env.urlFrom(t, editPage, `action="(/hook/[^/"]+/edit)"`, cookies),
 		form, cookies,
 	)
-	require.Equal(t, http.StatusSeeOther, w.Code)
-	assert.Equal(t, page, w.Header().Get("Location"))
+	env.requireNotice(t, w, page, "webhook-saved", "Webhook saved.", cookies)
 
 	var edited database.Webhook
 
@@ -906,16 +948,17 @@ func TestHook_EditFormAndDelete(t *testing.T) {
 		env.urlFrom(t, page, `action="(/hook/[^/"]+/delete)"`, cookies),
 		form, cookies,
 	)
-	require.Equal(t, http.StatusSeeOther, w.Code)
-	assert.Equal(t, "/hooks", w.Header().Get("Location"))
+	env.requireNotice(
+		t, w, "/hooks", "webhook-deleted", "Webhook deleted.", cookies,
+	)
 	assert.Equal(
 		t, http.StatusNotFound, env.get(page, cookies).Code,
 		"a deleted webhook's page should be gone",
 	)
 }
 
-// TestHook_EntrypointActions adds, deactivates and deletes an
-// entrypoint with the forms on the webhook page, each submitted to
+// TestHook_EntrypointActions adds, deactivates, activates and deletes
+// an entrypoint with the forms on the webhook page, each submitted to
 // the action and with the token the page rendered.
 func TestHook_EntrypointActions(t *testing.T) {
 	t.Parallel()
@@ -933,16 +976,19 @@ func TestHook_EntrypointActions(t *testing.T) {
 	form.Set("csrf_token", token)
 
 	// submit posts the webhook page's form whose action pattern
-	// captures, and requires the redirect back to that page.
-	submit := func(pattern string) {
+	// captures, and requires the redirect back to that page with the
+	// notice code, and the page to show text.
+	submit := func(pattern, code, text string) {
 		t.Helper()
 
 		w := env.post(env.urlFrom(t, page, pattern, cookies), form, cookies)
-		require.Equal(t, http.StatusSeeOther, w.Code)
-		require.Equal(t, page, w.Header().Get("Location"))
+		env.requireNotice(t, w, page, code, text, cookies)
 	}
 
-	submit(`action="(/hook/[^/"]+/entrypoints)"`)
+	toggle := `action="(/hook/[^/"]+/entrypoints/[^/"]+/toggle)"`
+
+	submit(`action="(/hook/[^/"]+/entrypoints)"`,
+		"entrypoint-added", "Entrypoint added.")
 
 	var added database.Entrypoint
 
@@ -951,7 +997,7 @@ func TestHook_EntrypointActions(t *testing.T) {
 	)
 	require.True(t, added.Active)
 
-	submit(`action="(/hook/[^/"]+/entrypoints/[^/"]+/toggle)"`)
+	submit(toggle, "entrypoint-deactivated", "Entrypoint deactivated.")
 
 	var toggled database.Entrypoint
 
@@ -960,7 +1006,10 @@ func TestHook_EntrypointActions(t *testing.T) {
 	)
 	assert.False(t, toggled.Active, "the toggle should deactivate it")
 
-	submit(`action="(/hook/[^/"]+/entrypoints/[^/"]+/delete)"`)
+	submit(toggle, "entrypoint-activated", "Entrypoint activated.")
+
+	submit(`action="(/hook/[^/"]+/entrypoints/[^/"]+/delete)"`,
+		"entrypoint-deleted", "Entrypoint deleted.")
 
 	var left int64
 
@@ -971,8 +1020,8 @@ func TestHook_EntrypointActions(t *testing.T) {
 
 // TestHook_TargetActions adds a target with the form on the webhook
 // page, follows its Edit link to the target edit form and submits
-// it, then deactivates and deletes it, every URL and token taken from
-// the rendered pages.
+// it, then deactivates, activates and deletes it, every URL and token
+// taken from the rendered pages.
 func TestHook_TargetActions(t *testing.T) {
 	t.Parallel()
 
@@ -987,27 +1036,29 @@ func TestHook_TargetActions(t *testing.T) {
 
 	// submit posts form, with the token, to the action pattern
 	// captures on the page at from, and requires the redirect back to
-	// the webhook page.
-	submit := func(from, pattern string, form url.Values) {
+	// the webhook page with the notice code, and that page to show
+	// text.
+	submit := func(from, pattern string, form url.Values, code, text string) {
 		t.Helper()
 
 		form.Set("csrf_token", token)
 
 		w := env.post(env.urlFrom(t, from, pattern, cookies), form, cookies)
-		require.Equal(t, http.StatusSeeOther, w.Code)
-		require.Equal(t, page, w.Header().Get("Location"))
+		env.requireNotice(t, w, page, code, text, cookies)
 	}
 
+	toggle := `action="(/hook/[^/"]+/targets/[^/"]+/toggle)"`
+
 	submit(page, `action="(/hook/[^/"]+/targets)"`, url.Values{
 		"name": {"added"},
 		"type": {string(database.TargetTypeLog)},
-	})
+	}, "target-added", "Target added.")
 
 	editPage := env.urlFrom(
 		t, page, `href="(/hook/[^/"]+/targets/[^/"]+/edit)"`, cookies,
 	)
 	submit(editPage, `action="(/hook/[^/"]+/targets/[^/"]+/edit)"`,
-		url.Values{"name": {"renamed"}})
+		url.Values{"name": {"renamed"}}, "target-saved", "Target saved.")
 
 	var edited database.Target
 
@@ -1017,8 +1068,8 @@ func TestHook_TargetActions(t *testing.T) {
 	assert.Equal(t, "renamed", edited.Name)
 	require.True(t, edited.Active)
 
-	submit(page, `action="(/hook/[^/"]+/targets/[^/"]+/toggle)"`,
-		url.Values{})
+	submit(page, toggle, url.Values{},
+		"target-deactivated", "Target deactivated.")
 
 	var toggled database.Target
 
@@ -1027,8 +1078,11 @@ func TestHook_TargetActions(t *testing.T) {
 	)
 	assert.False(t, toggled.Active, "the toggle should deactivate it")
 
+	submit(page, toggle, url.Values{},
+		"target-activated", "Target activated.")
+
 	submit(page, `action="(/hook/[^/"]+/targets/[^/"]+/delete)"`,
-		url.Values{})
+		url.Values{}, "target-deleted", "Target deleted.")
 
 	var left int64
 
@@ -1064,9 +1118,9 @@ func TestHook_ResubmitFromEventLog(t *testing.T) {
 		env.urlFrom(t, logsPath, `action="(/hook/[^"]+/resubmit)"`, cookies),
 		form, cookies,
 	)
-	require.Equal(t, http.StatusSeeOther, w.Code)
-	assert.Equal(
-		t, logsPath+"?resubmit=no-targets", w.Header().Get("Location"),
+	env.requireNotice(
+		t, w, logsPath, "resubmit-no-targets",
+		"this source has no active targets", cookies,
 	)
 
 	webhookDB, err := env.dbMgr.GetDB(wh.ID)
@@ -1302,10 +1356,8 @@ func TestDeliveryReplay_PostOnlyAndCSRFProtected(t *testing.T) {
 		html.UnescapeString(action[1]), form, cookies,
 	)
 
-	require.Equal(t, http.StatusSeeOther, w.Code)
-	assert.Equal(
-		t, logsPath+"?replay=queued",
-		w.Header().Get("Location"),
+	env.requireNotice(
+		t, w, logsPath, "replay-queued", "Replay queued:", cookies,
 	)
 	assert.Equal(
 		t, int64(2), env.countDeliveries(t, wh.ID),
@@ -1524,3 +1576,31 @@ func TestTwoMetricsRoutersInOneProcess(t *testing.T) {
 		}
 	}
 }
+
+// TestMetricsScrapeBeforeAnyDelivery pins
+// https://git.eeqj.de/sneak/webhooker/issues/267: an instance that
+// has delivered nothing must still serve the delivery duration
+// histogram, at zero, for every target type.
+func TestMetricsScrapeBeforeAnyDelivery(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnvWithConfig(
+		t, metricsConfig(t, metricsUser, metricsAuthValue),
+	)
+
+	scrape := env.metricsRequest(metricsUser, metricsAuthValue)
+	require.Equal(t, http.StatusOK, scrape.Code)
+
+	for _, targetType := range []database.TargetType{
+		database.TargetTypeHTTP,
+		database.TargetTypeDatabase,
+		database.TargetTypeLog,
+		database.TargetTypeSlack,
+	} {
+		assert.Contains(
+			t, scrape.Body.String(),
+			`webhooker_delivery_duration_seconds_count{target_type="`+
+				string(targetType)+`"} 0`,
+		)
+	}
+}

templates/base.html

@@ -7,6 +7,7 @@
 <body class="bg-gray-50 min-h-screen flex flex-col">
     <div class="flex-grow">
         {{template "navbar" .}}
+        {{template "notice" .}}
         {{block "content" .}}{{end}}
     </div>
     {{template "footer" .}}

templates/notice.html

@@ -0,0 +1,7 @@
+{{define "notice"}}
+{{with .Notice}}
+<div class="max-w-6xl mx-auto px-6 pt-4">
+    <div class="{{if .Failed}}alert-error{{else}}alert-success{{end}}">{{.Text}}</div>
+</div>
+{{end}}
+{{end}}

templates/source_detail.html

@@ -3,10 +3,14 @@
 {{define "title"}}{{.Webhook.Name}} - Webhooker{{end}}
 
 {{define "content"}}
-<div class="max-w-6xl mx-auto px-6 py-8" x-data="{ showAddEntrypoint: false, showAddTarget: false }">
+<!-- 108rem, half again the 72rem (max-w-6xl) of the webhook list, the
+     event log, the navbar and the footer, so an entrypoint URL fits on
+     one line. An inline style, because the committed tailwind.css has
+     no class this wide. -->
+<div class="mx-auto px-6 py-8" style="max-width: 108rem" x-data="{ showAddEntrypoint: false, showAddTarget: false }">
     <div class="mb-6">
         <a href="/hooks" class="text-sm text-primary-600 hover:text-primary-700">&larr; Back to webhooks</a>
-        <div class="flex justify-between items-center mt-2">
+        <div class="flex flex-wrap justify-between items-center gap-2 mt-2">
             <div>
                 <h1 class="text-2xl font-medium text-gray-900">{{.Webhook.Name}}</h1>
                 {{if .Webhook.Description}}

templates/source_logs.html

@@ -12,14 +12,6 @@
         </div>
     </div>
 
-    {{if .ReplayMessage}}
-    <div class="{{if .ReplayQueued}}alert-success{{else}}alert-error{{end}}">{{.ReplayMessage}}</div>
-    {{end}}
-
-    {{if .ResubmitMessage}}
-    <div class="{{if .ResubmitQueued}}alert-success{{else}}alert-error{{end}}">{{.ResubmitMessage}}</div>
-    {{end}}
-
     <div class="card">
         <div class="divide-y divide-gray-100">
             {{range .Events}}