Deploy main eacf1e7 to prod

Replaces #559, which conflicted.

Model: opus-5-5

internal/server/server.go

@@ -39,6 +39,12 @@ const (
 	// refuses to spend, leaving it for the hooks that run after the
 	// server: the delivery engine, the healthcheck, the webhook DB
 	// manager and the database close.
+	//
+	// Its value is not tuned to those hooks, which take about a
+	// millisecond between them. It is what the 5s fx stop timeout in
+	// cmd/webhooker leaves after a full ShutdownTimeout drain, so a
+	// drain that starts on a full budget still gets all of
+	// ShutdownTimeout.
 	TailHookReserve = 2 * time.Second
 
 	// sentryFlushTimeout is the longest wait for Sentry to flush
@@ -59,6 +65,16 @@ const (
 // key off it, and a zero exit would read as a deliberate stop.
 const StartupFailureExitCode = 1
 
+// DrainBudget reports how long the HTTP drain may wait for in-flight
+// requests when remaining is the time left on the fx stop context as
+// the server's stop hook starts. The hooks before the server can
+// already have spent part of the budget, so the drain takes its time
+// out of what they left, never out of TailHookReserve. Zero or less
+// means no wait at all.
+func DrainBudget(remaining time.Duration) time.Duration {
+	return min(ShutdownTimeout, remaining-TailHookReserve)
+}
+
 // SentryFlushBudget reports how long the Sentry flush may run when
 // remaining is the time left on the fx stop context after the HTTP
 // drain. sentry.Flush takes a bare duration and honours no context,
@@ -119,6 +135,8 @@ func New(lc fx.Lifecycle, params ServerParams) (*Server, error) {
 	s.httpServer = s.newHTTPServer()
 
 	lc.Append(fx.Hook{
+		//nolint:contextcheck // The listener outlives this hook, whose
+		// context fx cancels once the app has started.
 		OnStart: func(_ context.Context) error {
 			s.startupTime = time.Now()
 			go s.Run()
@@ -159,12 +177,6 @@ func (s *Server) Run() {
 	s.serve()
 }
 
-// MaintenanceMode returns whether the server is in maintenance
-// mode.
-func (s *Server) MaintenanceMode() bool {
-	return s.params.Config.MaintenanceMode
-}
-
 // enableSentry initialises the Sentry SDK when error reporting is
 // configured, and reports the failure when it is configured and cannot
 // be initialised. A DSN that is not set is not a failure: reporting
@@ -267,10 +279,17 @@ func (s *Server) cleanupForExit() {
 	s.log.Info("cleaning up")
 }
 
+// cleanShutdown drains the HTTP server and flushes Sentry inside what
+// is left of the fx stop budget. A context carrying no deadline — a
+// caller outside the fx lifecycle — gets the full ShutdownTimeout.
 func (s *Server) cleanShutdown(ctx context.Context) {
-	ctxShutdown, shutdownCancel := context.WithTimeout(
-		ctx, ShutdownTimeout,
-	)
+	drain := ShutdownTimeout
+
+	if deadline, ok := ctx.Deadline(); ok {
+		drain = DrainBudget(time.Until(deadline))
+	}
+
+	ctxShutdown, shutdownCancel := context.WithTimeout(ctx, drain)
 	defer shutdownCancel()
 
 	err := s.httpServer.Shutdown(ctxShutdown)