Correct release-blocking documentation inaccuracies (closes #141)

Four defects found by the integration review, each of which would have
made the README or the release notes untrue at the moment of tagging.

RETENTION_SWEEP_INTERVAL was absent from the README env table while two
other passages referred to it as documented. Enumerated every variable
read by internal/config from the source (12 in total) rather than by
eye; that was the only one missing.

TODO.md omitted five of the units landed in this milestone (#64, #79,
#90, #113, #118), two of them credential-exposure fixes, which are
precisely the entries a reader of the release notes wants to find. The
list is now derived from git log origin/main..origin/next.

The README sold Replay in the present tense as a core capability while
no redelivery code exists anywhere in the tree, and the roadmap entry
for it had been dropped without it being implemented. The README now
says planned, and the roadmap entry is back.

The production JS asset shipped a console.log on load. The rest of the
file and every other shipped asset were checked; that was the only one
(alpine.min.js is vendored and untouched).

No behavioural change: the only non-documentation edit is the deleted
console.log.

README.md

@@ -93,6 +93,7 @@ TTY detection, and security headers are always applied.
 | `METRICS_USERNAME`      | Basic auth username for `/metrics`  | `""`     |
 | `METRICS_PASSWORD`      | Basic auth password for `/metrics`  | `""`     |
 | `SENTRY_DSN`            | Sentry error reporting DSN          | `""`     |
+| `RETENTION_SWEEP_INTERVAL` | How often the retention reaper and archive sweeper run (Go duration) | `1h` |
 | `SESSION_IDLE_TIMEOUT`  | Idle session timeout (Go duration)  | `24h`    |
 | `RECEIVER_RATE_LIMIT`   | Receiver requests/minute per IP per entrypoint | `120` |
 | `TRUSTED_PROXIES`       | CIDRs whose forwarded headers are trusted | `""` (none) |
@@ -260,9 +261,10 @@ webhooker solves this by acting as a durable intermediary:
    targets simultaneously. This enables patterns like forwarding a
    GitHub webhook to both a deployment service and a Slack channel.
 
-5. **Replay** — Stored events can be manually redelivered for debugging
-   or testing, without requiring the original sender to fire the webhook
-   again.
+5. **Replay** (not yet implemented) — Every received event is stored in
+   full, which is what manual redelivery for debugging or testing will
+   be built on. No redelivery exists today, in the web UI or the API;
+   see [TODO.md](TODO.md).
 
 ### Use Cases
 
@@ -272,6 +274,7 @@ webhooker solves this by acting as a durable intermediary:
   size, and delivery performance
 - **Debugging** and introspection of webhook payloads in the web UI
 - **Replay** of webhook events for application testing and development
+  (planned; not yet implemented)
 - **Fan-out** delivery of a single webhook to multiple downstream
   targets
 - **High-availability ingestion** for delivery to less reliable backend

TODO.md

@@ -1,35 +1,94 @@
 # Workflow
 
-* branch (from `main`)
-* do the work in Next Step
-* move Next Step to the top of Completed Steps
-* move the top item of Future Steps into Next Step
-* commit (`TODO.md` changes in the same commit as the work)
-* merge to `main` if the branch is not protected, otherwise open a PR
-* push
+One issue per unit of work, one branch and one PR per issue:
+
+* ensure a tracked issue exists with a definition of done
+* branch from `next` (never from `main`)
+* do the work; open a PR based on `next` (never on `main`)
+* pass an independent review, then the manager squash-merges into `next`
+* push; nothing stays local-only
+
+`next` is the branch for the next milestone and must stay green and
+mergeable to `main` without notice. One `next` -> `main` PR accumulates
+the milestone; releases are cut from `main` separately.
+
+Issue branches do NOT touch this file — the manager maintains it on
+`next`. Every branch editing `TODO.md` conflicts with every other
+(#112).
 
 # Status
 
-pre-1.0. No git tags exist. main (4f5ecb1) is a working webhook proxy
+pre-1.0. No git tags exist. `main` (4f5ecb1) is a working webhook proxy
 with auth, CSRF/SSRF protections, login rate limiting, Slack target,
 event retention (#63), the database archiving target (#43), the admin
 password change flow (#65), policy compliance (#6), pinned lint tooling
-(#55), and fail-loud configuration parsing (#80). Note: TODO.md was
-deliberately deleted from this repo in f9a9569 (2026-03-01, #6); its
-content was folded into the README TODO section, which this draft
-reconstructs as of 2026-07-06.
+(#55), and fail-loud configuration parsing (#80).
+
+`next` (9bfd033) holds the completed 1.0.0 milestone: every issue in it
+is closed, and it is verified green by cache-defeated container runs
+rather than by the CI badge, which can pass without executing anything
+(#119). Note: TODO.md was deliberately deleted from this repo in f9a9569
+(2026-03-01, #6); its content was folded into the README TODO section,
+which this draft reconstructs as of 2026-07-06.
 
 # Next Step
 
-Manual event redelivery from the web UI (replay is a core promised
-capability in the README rationale).
+Tag 1.0.0 from `main` once the milestone PR merges, then repair the CI
+gate (#119) before the next cycle's work lands — a gate that can report
+success without running is the one thing every other guarantee here
+rests on.
 
 # Completed Steps
 
+- 2026-08-12 Bound the `X-Forwarded-For` scan's allocation to the hop
+  cap: the reverse walk cuts entries with `strings.LastIndexByte`
+  instead of joining and splitting, so a 1 MB header allocates 16 bytes
+  rather than 1.6 MB per request on the unauthenticated receiver.
+  Semantics proven unchanged by differential testing against the
+  previous implementation (#133)
+- 2026-08-12 Cap the `X-Forwarded-For` hop walk at 64 entries, so an
+  attacker-supplied chain cannot burn unbounded CPU in the rate-limit
+  key function; running off the end falls back to the peer address
+  (#124)
+- 2026-08-12 Gate forwarded-header trust behind a `TRUSTED_PROXIES` CIDR
+  list: all three rate limiters key on the connection's own address
+  unless the direct peer is a configured proxy, in which case
+  `X-Forwarded-For` is walked right to left for the first non-proxy hop.
+  Default trusts nothing, and a set-but-unparseable value aborts
+  startup. Before this, any client could mint a fresh bucket or drain
+  another's by rotating a spoofed header (#88)
 - 2026-08-11 Web UI cleanup: nav terminology unified on Webhooks, the
   Profile settings placeholder removed, a progressive-enhancement copy
   button for the entrypoint URL, and retention form copy that states the
   actual policy (deletion by the reaper, 0 retains forever) (#57)
+- 2026-08-11 Mask the webhook credential in delivery errors and logs:
+  Go embeds the request URL in `*url.Error`, so every transport failure
+  persisted the full Slack webhook URL into the per-webhook event
+  database via `DeliveryResult.Error`, a field a future REST API would
+  have served. `maskURLError` drops path, query and userinfo while
+  preserving the wrapped cause, so `errors.Is`/`As` and `Timeout()`
+  still work and DNS, TLS and timeout failures still read differently
+  (#118)
+- 2026-08-11 Rate-limit the public webhook receiver endpoint
+  (`RECEIVER_RATE_LIMIT`, default 120/min), keyed on client IP plus
+  entrypoint path so one entrypoint cannot exhaust another's budget;
+  over-limit requests get 429 with `Retry-After`. It was the one
+  unauthenticated, internet-facing endpoint with no limit at all (#64)
+- 2026-08-11 Enforce the body size limit before CSRF parses the form:
+  `MaxBodySize` is now first in all four form-parsing route groups, so
+  an oversized request is rejected with 413 instead of being read in
+  full by the CSRF middleware before any cap applied (#90)
+- 2026-08-11 Mask target config on the source detail page, which
+  rendered the stored blob verbatim and so exposed the Slack
+  incoming-webhook URL — a bearer credential that cannot be revoked
+  per-holder. Config reaches the template only as a `TargetView` of
+  labelled fields, and header values are rendered as a count (#113)
+- 2026-08-11 Allow `retention_days` of 0 to mean retain forever, via a
+  sentinel written in `BeforeSave` so the GORM column default cannot
+  win the race. Also bounds the reaper's cutoff arithmetic: day counts
+  above 106751 overflowed `time.Duration` and wrapped the cutoff into
+  the future, where every row matched and the sweep deleted everything
+  (#79)
 - 2026-08-09 Inactivity-based session timeout: sliding idle expiry
   (`SESSION_IDLE_TIMEOUT`, default `24h`) refreshed on authenticated
   requests, with the 7-day absolute cap kept as an independent
@@ -84,6 +143,9 @@ capability in the README rationale).
 
 # Future Steps
 
+- Manual event redelivery from the web UI — the "Replay" capability the
+  README describes as planned. No redelivery code exists anywhere in the
+  tree; events are stored in full, which is all it would be built on
 - Delivery status and retry management UI
 - Per-webhook rate limiting in the receiver handler (per-webhook config
   plus handler enforcement; global limits must not apply to receiver

internal/database/export_test.go

@@ -46,19 +46,8 @@ func (r *RetentionReaper) ExportStart() {
 }
 
 // ExportStop stops the reaper's background loop for tests.
-func (r *RetentionReaper) ExportStop(ctx context.Context) error {
-	return r.stop(ctx)
-}
-
-// ExportWedgeLoop adds a goroutine to the reaper's WaitGroup that
-// never observes cancellation and returns only when release is
-// closed. It stands in for a sweep stuck on a locked database.
-func (r *RetentionReaper) ExportWedgeLoop(
-	release <-chan struct{},
-) {
-	r.wg.Go(func() {
-		<-release
-	})
+func (r *RetentionReaper) ExportStop() {
+	r.stop()
 }
 
 // ExportSetInterval overrides the sweep interval for tests.

internal/database/retention.go

@@ -10,7 +10,6 @@ import (
 	"go.uber.org/fx"
 	"gorm.io/gorm"
 	"sneak.berlin/go/webhooker/internal/config"
-	"sneak.berlin/go/webhooker/internal/lifecycle"
 	"sneak.berlin/go/webhooker/internal/logger"
 )
 
@@ -63,9 +62,8 @@ func NewRetentionReaper(
 }
 
 // registerHooks wires the reaper's start and stop into the fx
-// lifecycle. The start hook's context is deliberately ignored (see
-// start for why the sweep loop must not inherit it); the stop hook's
-// context is honoured (see stop).
+// lifecycle. The start hook's context is deliberately ignored: see
+// start for why the sweep loop must not inherit it.
 func (r *RetentionReaper) registerHooks(lc fx.Lifecycle) {
 	lc.Append(fx.Hook{
 		//nolint:contextcheck // Not inheriting the hook context is
@@ -75,8 +73,10 @@ func (r *RetentionReaper) registerHooks(lc fx.Lifecycle) {
 
 			return nil
 		},
-		OnStop: func(ctx context.Context) error {
-			return r.stop(ctx)
+		OnStop: func(_ context.Context) error {
+			r.stop()
+
+			return nil
 		},
 	})
 }
@@ -105,27 +105,15 @@ func (r *RetentionReaper) start() {
 	)
 }
 
-// stop cancels the sweep loop's context and waits for it to
-// exit, bounded by the stop hook's context: a sweep wedged on a
-// locked database must not hang the process past fx's stop
-// timeout.
-func (r *RetentionReaper) stop(ctx context.Context) error {
+func (r *RetentionReaper) stop() {
 	r.log.Info("retention reaper stopping")
 
 	if r.cancel != nil {
 		r.cancel()
 	}
 
-	err := lifecycle.WaitForShutdown(
-		ctx, r.log, "retention reaper", &r.wg,
-	)
-	if err != nil {
-		return err
-	}
-
+	r.wg.Wait()
 	r.log.Info("retention reaper stopped")
-
-	return nil
 }
 
 func (r *RetentionReaper) run(ctx context.Context) {

internal/database/retention_lifecycle_test.go

@@ -26,13 +26,6 @@ const (
 	// reaperTestRetentionDays is the retention policy the lifecycle
 	// tests give their webhook.
 	reaperTestRetentionDays = 30
-
-	// reaperWedgeStopTimeout is the stop timeout the wedged-shutdown
-	// test hands OnStop, standing in for fx's StopTimeout. The test
-	// asserts only that the hook returns at all, and allows it
-	// reaperStopTimeout — forty times this budget — to do so, so no
-	// assertion races the wall clock.
-	reaperWedgeStopTimeout = 250 * time.Millisecond
 )
 
 // recordingLifecycle is a minimal fx.Lifecycle that records the
@@ -214,59 +207,3 @@ func TestRetentionReaper_StopHookStopsLoop(t *testing.T) {
 		"a stopped reaper must not sweep anything",
 	)
 }
-
-// TestRetentionReaper_StopHookHonoursStopTimeout is the
-// regression test for a shutdown that could never complete. fx
-// hands OnStop a context carrying the application's stop timeout;
-// an OnStop that discards it and calls wg.Wait() bare hangs the
-// process forever on a sweep blocked on a locked SQLite database
-// — precisely when a bounded shutdown matters most.
-//
-// The wedged goroutine here never observes cancellation, so the
-// hook can only return by honouring its context, and it must say
-// so rather than reporting a clean stop.
-func TestRetentionReaper_StopHookHonoursStopTimeout(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	env := setupRetentionTest(t)
-
-	env.reaper.ExportSetInterval(reaperTestInterval)
-
-	lc := startReaperViaHook(t, env.reaper)
-
-	release := make(chan struct{})
-
-	t.Cleanup(func() { close(release) })
-
-	env.reaper.ExportWedgeLoop(release)
-
-	stopCtx, cancel := context.WithTimeout(
-		context.Background(), reaperWedgeStopTimeout,
-	)
-	defer cancel()
-
-	var stopErr error
-
-	stopped := make(chan struct{})
-
-	go func() {
-		defer close(stopped)
-
-		stopErr = lc.hooks[0].OnStop(stopCtx)
-	}()
-
-	select {
-	case <-stopped:
-	case <-time.After(reaperStopTimeout):
-		t.Fatal(
-			"OnStop did not return: it discarded the stop " +
-				"context and is waiting on a wedged goroutine " +
-				"that will never observe cancellation",
-		)
-	}
-
-	require.ErrorIs(t, stopErr, context.DeadlineExceeded)
-	require.ErrorContains(t, stopErr, "retention reaper")
-}

internal/delivery/archive_sweeper.go

@@ -10,7 +10,6 @@ import (
 	"go.uber.org/fx"
 	"sneak.berlin/go/webhooker/internal/config"
 	"sneak.berlin/go/webhooker/internal/database"
-	"sneak.berlin/go/webhooker/internal/lifecycle"
 	"sneak.berlin/go/webhooker/internal/logger"
 )
 
@@ -68,9 +67,10 @@ func NewArchiveSweeper(
 }
 
 // registerHooks wires the sweeper's start and stop into the fx
-// lifecycle. The start hook's context is deliberately ignored
-// (see start for why the background loop must not inherit it);
-// the stop hook's context is honoured (see stop).
+// lifecycle. Both hook contexts are deliberately ignored: see
+// start for why the background loop must not inherit the start
+// hook's context, and stop for why shutdown blocks on the loop
+// rather than on the stop hook's deadline.
 func (s *ArchiveSweeper) registerHooks(lc fx.Lifecycle) {
 	lc.Append(fx.Hook{
 		//nolint:contextcheck // Not passing the hook context is
@@ -80,8 +80,10 @@ func (s *ArchiveSweeper) registerHooks(lc fx.Lifecycle) {
 
 			return nil
 		},
-		OnStop: func(ctx context.Context) error {
-			return s.stop(ctx)
+		OnStop: func(_ context.Context) error {
+			s.stop()
+
+			return nil
 		},
 	})
 }
@@ -111,27 +113,15 @@ func (s *ArchiveSweeper) start() {
 	)
 }
 
-// stop cancels the sweep loop's context and waits for it to
-// exit, bounded by the stop hook's context: a prune wedged on a
-// locked archive must not hang the process past fx's stop
-// timeout.
-func (s *ArchiveSweeper) stop(ctx context.Context) error {
+func (s *ArchiveSweeper) stop() {
 	s.log.Info("archive sweeper stopping")
 
 	if s.cancel != nil {
 		s.cancel()
 	}
 
-	err := lifecycle.WaitForShutdown(
-		ctx, s.log, "archive sweeper", &s.wg,
-	)
-	if err != nil {
-		return err
-	}
-
+	s.wg.Wait()
 	s.log.Info("archive sweeper stopped")
-
-	return nil
 }
 
 func (s *ArchiveSweeper) run(ctx context.Context) {

internal/delivery/archive_sweeper_test.go

@@ -14,6 +14,7 @@ import (
 	"github.com/google/uuid"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"go.uber.org/fx"
 	"gorm.io/driver/sqlite"
 	"gorm.io/gorm"
 	"gorm.io/gorm/clause"
@@ -225,6 +226,17 @@ func countArchivedRows(path string) (int64, error) {
 	return count, nil
 }
 
+// captureLifecycle is a minimal fx.Lifecycle that records the
+// hooks a component registers, so a test can invoke the real
+// OnStart/OnStop functions with a context of its choosing.
+type captureLifecycle struct {
+	hooks []fx.Hook
+}
+
+func (l *captureLifecycle) Append(h fx.Hook) {
+	l.hooks = append(l.hooks, h)
+}
+
 // TestArchiveSweeper_LoopOutlivesStartHookContext is the
 // regression test for a sweeper that never swept. fx calls
 // OnStart with a context carrying the application's start
@@ -258,7 +270,7 @@ func TestArchiveSweeper_LoopOutlivesStartHookContext(
 
 	// Drive the genuine fx hooks the application registers,
 	// rather than a test-only entry point.
-	lc := &recordingLifecycle{}
+	lc := &captureLifecycle{}
 	env.sweeper.ExportRegisterHooks(lc)
 	require.Len(t, lc.hooks, 1)
 
@@ -912,36 +924,7 @@ func TestArchiveSweeper_StopsCleanly(t *testing.T) {
 	env.sweeper.ExportSetInterval(time.Millisecond)
 	env.sweeper.ExportStart()
 
-	// stop blocks on the loop's WaitGroup, so returning without
-	// error proves the loop observed the cancellation and exited
-	// well inside the stop context.
-	require.NoError(
-		t, env.sweeper.ExportStop(context.Background()),
-	)
-}
-
-// TestArchiveSweeper_StopHookHonoursStopTimeout is the sweeper's
-// half of the same shutdown defect the engine and the retention
-// reaper carried: an OnStop that discards its context and waits
-// on the WaitGroup bare hangs the process forever on a prune
-// wedged inside a locked archive.
-func TestArchiveSweeper_StopHookHonoursStopTimeout(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	env := setupSweeperTest(t)
-
-	lc := &recordingLifecycle{}
-	env.sweeper.ExportRegisterHooks(lc)
-	require.Len(t, lc.hooks, 1)
-	require.NoError(t, lc.hooks[0].OnStart(context.Background()))
-
-	release := make(chan struct{})
-
-	t.Cleanup(func() { close(release) })
-
-	env.sweeper.ExportWedgeLoop(release)
-
-	requireStopHookExpires(t, lc.hooks[0], "archive sweeper")
+	// stop blocks on the loop's WaitGroup, so returning at all
+	// proves the loop observed the cancellation and exited.
+	env.sweeper.ExportStop()
 }

internal/delivery/engine.go

@@ -13,7 +13,6 @@ import (
 	"go.uber.org/fx"
 	"gorm.io/gorm"
 	"sneak.berlin/go/webhooker/internal/database"
-	"sneak.berlin/go/webhooker/internal/lifecycle"
 	"sneak.berlin/go/webhooker/internal/logger"
 )
 
@@ -235,9 +234,8 @@ func (e *Engine) ScheduleRetry(
 }
 
 // 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
-// stop hook's context is honoured (see stop).
+// lifecycle. The start hook's context is deliberately ignored:
+// see start for why the worker pool must not inherit it.
 func (e *Engine) registerHooks(lc fx.Lifecycle) {
 	lc.Append(fx.Hook{
 		//nolint:contextcheck // Not inheriting the hook context
@@ -247,8 +245,10 @@ func (e *Engine) registerHooks(lc fx.Lifecycle) {
 
 			return nil
 		},
-		OnStop: func(ctx context.Context) error {
-			return e.stop(ctx)
+		OnStop: func(_ context.Context) error {
+			e.stop()
+
+			return nil
 		},
 	})
 }
@@ -289,26 +289,11 @@ func (e *Engine) start() {
 	)
 }
 
-// stop cancels the worker pool's context and waits for the pool
-// to drain, bounded by the stop hook's context: a wedged worker
-// must not hang the process past fx's stop timeout.
-func (e *Engine) stop(ctx context.Context) error {
+func (e *Engine) stop() {
 	e.log.Info("delivery engine stopping")
-
-	if e.cancel != nil {
 	e.cancel()
-	}
-
-	err := lifecycle.WaitForShutdown(
-		ctx, e.log, "delivery engine", &e.wg,
-	)
-	if err != nil {
-		return err
-	}
-
+	e.wg.Wait()
 	e.log.Info("delivery engine stopped")
-
-	return nil
 }
 
 func (e *Engine) worker(ctx context.Context) {

internal/delivery/engine_integration_test.go

@@ -501,7 +501,7 @@ func TestWorkerLifecycle_StartStop(t *testing.T) {
 
 	iWaitForDelivered(t, s.WebhookDB, d.ID)
 
-	require.NoError(t, s.Engine.ExportStop(context.Background()))
+	s.Engine.ExportStop()
 }
 
 // iWaitForDelivered polls until the delivery reaches the
@@ -567,7 +567,7 @@ func TestWorkerLifecycle_ProcessesRetryChannel(
 
 	iWaitForDelivered(t, s.WebhookDB, d.ID)
 
-	require.NoError(t, s.Engine.ExportStop(context.Background()))
+	s.Engine.ExportStop()
 }
 
 // --- processDelivery: unknown target type ---

internal/delivery/engine_lifecycle_test.go

@@ -27,13 +27,6 @@ const (
 	// and a ready deliveryCh are chosen between at random and a
 	// doomed pool still delivers.
 	hookSettleDelay = 250 * time.Millisecond
-
-	// wedgeStopTimeout is the stop timeout a wedged-shutdown test
-	// hands OnStop, standing in for fx's StopTimeout. The test
-	// asserts only that the hook returns at all, and allows it
-	// hookStopTimeout — forty times this budget — to do so, so no
-	// assertion here races the wall clock.
-	wedgeStopTimeout = 250 * time.Millisecond
 )
 
 // recordingLifecycle is a minimal fx.Lifecycle that records the
@@ -47,44 +40,6 @@ func (l *recordingLifecycle) Append(h fx.Hook) {
 	l.hooks = append(l.hooks, h)
 }
 
-// requireStopHookExpires drives hook.OnStop with a stop context
-// that expires while a wedged goroutine is still running, and
-// requires the hook to return the deadline error naming
-// component instead of blocking on the WaitGroup forever.
-func requireStopHookExpires(
-	t *testing.T, hook fx.Hook, component string,
-) {
-	t.Helper()
-
-	stopCtx, cancel := context.WithTimeout(
-		context.Background(), wedgeStopTimeout,
-	)
-	defer cancel()
-
-	var stopErr error
-
-	stopped := make(chan struct{})
-
-	go func() {
-		defer close(stopped)
-
-		stopErr = hook.OnStop(stopCtx)
-	}()
-
-	select {
-	case <-stopped:
-	case <-time.After(hookStopTimeout):
-		t.Fatal(
-			"OnStop did not return: it discarded the stop " +
-				"context and is waiting on a wedged goroutine " +
-				"that will never observe cancellation",
-		)
-	}
-
-	require.ErrorIs(t, stopErr, context.DeadlineExceeded)
-	require.ErrorContains(t, stopErr, component)
-}
-
 // startEngineViaHook drives the genuine fx hooks the application
 // registers for the engine, handing OnStart a context that is
 // already done, and returns only once a pool that inherited that
@@ -242,30 +197,3 @@ func TestEngine_StopHookStopsWorkers(t *testing.T) {
 		"a stopped engine must not deliver anything",
 	)
 }
-
-// TestEngine_StopHookHonoursStopTimeout is the regression test
-// for a shutdown that could never complete. fx hands OnStop a
-// context carrying the application's stop timeout; an OnStop
-// that discards it and calls wg.Wait() bare hangs the process
-// forever on a single worker stuck inside a delivery target that
-// never returns — precisely when a bounded shutdown matters
-// most.
-//
-// The wedged goroutine here never observes cancellation, so the
-// hook can only return by honouring its context, and it must say
-// so rather than reporting a clean stop.
-func TestEngine_StopHookHonoursStopTimeout(t *testing.T) {
-	t.Parallel()
-
-	s := newISetup(t)
-
-	lc := startEngineViaHook(t, s.Engine)
-
-	release := make(chan struct{})
-
-	t.Cleanup(func() { close(release) })
-
-	s.Engine.ExportWedgeWorker(release)
-
-	requireStopHookExpires(t, lc.hooks[0], "delivery engine")
-}

internal/delivery/export_test.go

@@ -216,19 +216,8 @@ func (e *Engine) ExportRegisterHooks(lc fx.Lifecycle) {
 }
 
 // ExportStop exposes stop for testing.
-func (e *Engine) ExportStop(ctx context.Context) error {
-	return e.stop(ctx)
-}
-
-// ExportWedgeWorker adds a goroutine to the engine's WaitGroup
-// that never observes cancellation and returns only when release
-// is closed. It stands in for a worker stuck inside a delivery
-// target that never returns, which is the only way stop can be
-// made to outlast its context.
-func (e *Engine) ExportWedgeWorker(release <-chan struct{}) {
-	e.wg.Go(func() {
-		<-release
-	})
+func (e *Engine) ExportStop() {
+	e.stop()
 }
 
 // ExportDeliveryCh returns the delivery channel.
@@ -529,19 +518,8 @@ func (s *ArchiveSweeper) ExportRegisterHooks(lc fx.Lifecycle) {
 }
 
 // ExportStop stops the sweeper's background loop for tests.
-func (s *ArchiveSweeper) ExportStop(ctx context.Context) error {
-	return s.stop(ctx)
-}
-
-// ExportWedgeLoop adds a goroutine to the sweeper's WaitGroup
-// that never observes cancellation and returns only when release
-// is closed. It stands in for a prune stuck on a locked archive.
-func (s *ArchiveSweeper) ExportWedgeLoop(
-	release <-chan struct{},
-) {
-	s.wg.Go(func() {
-		<-release
-	})
+func (s *ArchiveSweeper) ExportStop() {
+	s.stop()
 }
 
 // ExportSetInterval overrides the sweep interval for tests.

internal/lifecycle/lifecycle.go

@@ -1,57 +0,0 @@
-// Package lifecycle holds helpers shared by the components that
-// register fx start and stop hooks.
-package lifecycle
-
-import (
-	"context"
-	"fmt"
-	"log/slog"
-	"sync"
-)
-
-// WaitForShutdown waits for wg to drain, bounded by ctx.
-//
-// fx hands OnStop a context carrying the application's stop
-// timeout. A bare wg.Wait() discards that deadline, so a single
-// goroutine that never observes cancellation — a delivery target
-// that never returns, a SQLite operation blocked on a lock —
-// hangs the process forever instead of letting it exit when the
-// timeout expires, which is exactly when a clean shutdown matters
-// most.
-//
-// On timeout it logs at error naming component and returns an
-// error: the goroutines are still running, and reporting success
-// would hide an unclean shutdown from the operator. The waiting
-// goroutine outlives this call and exits when (if) wg drains; it
-// holds nothing but the channel it closes.
-func WaitForShutdown(
-	ctx context.Context,
-	log *slog.Logger,
-	component string,
-	wg *sync.WaitGroup,
-) error {
-	done := make(chan struct{})
-
-	go func() {
-		defer close(done)
-
-		wg.Wait()
-	}()
-
-	select {
-	case <-done:
-		return nil
-	case <-ctx.Done():
-		log.Error(
-			"shutdown timed out, goroutines still running",
-			"component", component,
-			"error", ctx.Err(),
-		)
-
-		return fmt.Errorf(
-			"%s: shutdown timed out, "+
-				"goroutines still running: %w",
-			component, ctx.Err(),
-		)
-	}
-}

internal/lifecycle/lifecycle_test.go

@@ -1,62 +0,0 @@
-package lifecycle_test
-
-import (
-	"context"
-	"log/slog"
-	"sync"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/require"
-	"sneak.berlin/go/webhooker/internal/lifecycle"
-)
-
-// waitTimeout is the stop budget the timeout case gives a
-// goroutine that never returns. The test's own patience is the
-// go test deadline, so the only thing this value affects is how
-// long the case takes.
-const waitTimeout = 100 * time.Millisecond
-
-func discardLogger() *slog.Logger {
-	return slog.New(slog.DiscardHandler)
-}
-
-func TestWaitForShutdown_DrainedGroup(t *testing.T) {
-	t.Parallel()
-
-	var wg sync.WaitGroup
-
-	wg.Go(func() {})
-
-	require.NoError(
-		t,
-		lifecycle.WaitForShutdown(
-			context.Background(), discardLogger(),
-			"test component", &wg,
-		),
-	)
-}
-
-func TestWaitForShutdown_ContextExpires(t *testing.T) {
-	t.Parallel()
-
-	release := make(chan struct{})
-
-	t.Cleanup(func() { close(release) })
-
-	var wg sync.WaitGroup
-
-	wg.Go(func() { <-release })
-
-	ctx, cancel := context.WithTimeout(
-		context.Background(), waitTimeout,
-	)
-	defer cancel()
-
-	err := lifecycle.WaitForShutdown(
-		ctx, discardLogger(), "test component", &wg,
-	)
-
-	require.ErrorIs(t, err, context.DeadlineExceeded)
-	require.ErrorContains(t, err, "test component")
-}

internal/middleware/export_test.go

@@ -25,6 +25,11 @@ func IPFromHostPort(hp string) string {
 	return ipFromHostPort(hp)
 }
 
+// ClientKeyForTest exposes clientKey for testing.
+func ClientKeyForTest(m *Middleware, r *http.Request) string {
+	return m.clientKey(r)
+}
+
 // IsClientTLS exposes isClientTLS for testing.
 func IsClientTLS(r *http.Request) bool {
 	return isClientTLS(r)

internal/middleware/ratelimit.go

@@ -32,6 +32,13 @@ const (
 	// receiver rate limit. The configured limit is expressed in
 	// requests per minute.
 	receiverRateInterval = 1 * time.Minute
+
+	// maxForwardedHops bounds how many X-Forwarded-For entries the
+	// chain walk examines. Real chains are one to three hops, but a
+	// client can pad the header up to MaxHeaderBytes, so without a
+	// bound every request pays a walk proportional to whatever the
+	// client sent.
+	maxForwardedHops = 64
 )
 
 // normalizeAddr strips the IPv4-in-IPv6 wrapper and any zone from
@@ -70,14 +77,36 @@ func (m *Middleware) isTrustedProxy(addr netip.Addr) bool {
 // a trusted proxy is the client. A hop that cannot be read as a bare
 // address ends the walk: past it the chain is not the shape assumed
 // here, so the caller falls back to the peer address.
+//
+// Only the last maxForwardedHops entries are examined. A longer chain
+// is padding, and running out of hops falls back to the peer address
+// the same way an unreadable hop does.
+//
+// The entries are cut off the right end of each header value in place
+// rather than split out of it: the receiver is unauthenticated and a
+// client can pad the header up to MaxHeaderBytes, so splitting would
+// allocate in proportion to the padding (about 8 MB for a 1 MB
+// header) before the cap could discard any of it. Multiple header
+// values are walked in reverse for the same reason, since joining
+// them copies the whole chain.
 func (m *Middleware) forwardedClientAddr(
 	r *http.Request,
 ) (netip.Addr, bool) {
-	hops := strings.Split(
-		strings.Join(r.Header.Values("X-Forwarded-For"), ","), ",",
-	)
+	seen := 0
+
+	for _, value := range slices.Backward(
+		r.Header.Values("X-Forwarded-For"),
+	) {
+		for last := false; !last && seen < maxForwardedHops; seen++ {
+			hop := value
+
+			comma := strings.LastIndexByte(value, ',')
+			if comma < 0 {
+				last = true
+			} else {
+				hop, value = value[comma+1:], value[:comma]
+			}
 
-	for _, hop := range slices.Backward(hops) {
 			hop = strings.TrimSpace(hop)
 			if hop == "" {
 				continue
@@ -92,6 +121,7 @@ func (m *Middleware) forwardedClientAddr(
 				return addr, true
 			}
 		}
+	}
 
 	return netip.Addr{}, false
 }
@@ -113,8 +143,10 @@ func (m *Middleware) clientKey(r *http.Request) string {
 	peer, err := netip.ParseAddr(ipFromHostPort(r.RemoteAddr))
 	if err != nil {
 		// Not an address we can reason about; key on the raw
-		// value rather than collapsing such peers into one
-		// shared bucket.
+		// value, the most specific identity left. On a
+		// Unix-socket listener every peer carries the same
+		// RemoteAddr and so shares one bucket, which is the
+		// fail-closed direction.
 		return r.RemoteAddr
 	}
 

internal/middleware/ratelimit_test.go

@@ -8,7 +8,10 @@ import (
 	"net/http/httptest"
 	"net/netip"
 	"os"
+	"runtime"
+	"strings"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 	"sneak.berlin/go/webhooker/internal/config"
@@ -568,6 +571,105 @@ func TestRateLimitKey_ChainWalkSkipsClientPrepended(t *testing.T) {
 	)
 }
 
+// TestRateLimitKey_LongChainCapsWalkAndFallsBackToPeer covers the
+// hop-walk cap. A client behind the trusted proxy can pad
+// X-Forwarded-For with tens of thousands of trusted-looking hops,
+// which costs a walk proportional to the padding and, once the walk
+// runs off the left end of the chain, reaches the entry the client
+// put there. Capping the walk stops both: the key falls back to the
+// peer address, so rotating the head of the chain mints no bucket,
+// and the run does not scale with the chain length.
+func TestRateLimitKey_LongChainCapsWalkAndFallsBackToPeer(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	// 50k hops is roughly 0.9 MB, within the default
+	// MaxHeaderBytes.
+	const hops = 50000
+
+	padding := strings.Repeat(", 10.0.0.2", hops-1)
+
+	start := time.Now()
+
+	assertSharedBucket(
+		t, trustedProxies("10.0.0.0/8"), "10.0.0.1:44444",
+		func(i int) map[string]string {
+			return map[string]string{
+				headerXFF: fmt.Sprintf("9.9.9.%d%s", i+1, padding),
+			}
+		},
+		"a padded X-Forwarded-For chain must fall back to the "+
+			"peer address, not reach the client-controlled entry "+
+			"at the head of the chain",
+	)
+
+	assert.Less(
+		t, time.Since(start), 2*time.Second,
+		"the capped walk must not scale with the chain length",
+	)
+}
+
+// TestRateLimitKey_LongChainAllocationIsBounded is the allocation
+// half of the hop cap. Capping the walk still left every request
+// paying for the whole header the client sent, because the chain was
+// split before it was capped: about 8 MB of []string for the 1 MB a
+// default MaxHeaderBytes allows, on the unauthenticated receiver.
+//
+// Bytes are the measurement, not allocation count: strings.Split of a
+// 1 MB chain is a single allocation, so testing.AllocsPerRun scores
+// it as cheap. The test is deliberately sequential — it reads
+// process-wide counters, and Go runs this package's parallel tests
+// only after the sequential ones finish.
+//
+//nolint:paralleltest // reads process-wide allocation counters
+func TestRateLimitKey_LongChainAllocationIsBounded(t *testing.T) {
+	// 100k hops of ", 10.0.0.2" is roughly 1 MB.
+	const (
+		hops            = 100000
+		iterations      = 50
+		maxBytesPerCall = 4096
+	)
+
+	m := rateLimitMiddleware(t, &config.Config{
+		TrustedProxies: trustedProxies("10.0.0.0/8"),
+	})
+
+	req := httptest.NewRequestWithContext(
+		context.Background(), http.MethodPost, loginPath, nil,
+	)
+	req.RemoteAddr = "10.0.0.1:44444"
+	req.Header.Set(
+		headerXFF, "9.9.9.9"+strings.Repeat(", 10.0.0.2", hops),
+	)
+
+	var before, after runtime.MemStats
+
+	var key string
+
+	runtime.ReadMemStats(&before)
+
+	for range iterations {
+		key = middleware.ClientKeyForTest(m, req)
+	}
+
+	runtime.ReadMemStats(&after)
+
+	perCall := (after.TotalAlloc - before.TotalAlloc) / iterations
+
+	assert.Less(
+		t, perCall, uint64(maxBytesPerCall),
+		"a %d-byte X-Forwarded-For must not allocate in proportion "+
+			"to its length, but cost %d bytes per call",
+		len(req.Header.Get(headerXFF)), perCall,
+	)
+
+	assert.Equal(
+		t, "10.0.0.1", key,
+		"the padded chain must still fall back to the peer address",
+	)
+}
+
 // TestReceiverRateLimit_IgnoresForwardedFromUntrustedPeer proves
 // the receiver limiter uses the same gated key function as the
 // POST limiters.

static/js/app.js

@@ -1,5 +1,4 @@
 // Webhooker client-side JavaScript
-console.log("Webhooker loaded");
 
 // Copy-to-clipboard, as progressive enhancement.
 //