Fix crash handling and log noise in logging feature

Review of the logging work from the previous commit turned up a real
correctness issue: the uncaughtException/unhandledRejection handlers
logged the error but let the process keep running, which silently
disabled Node's default crash-on-fatal-error behavior and could leave
a zombie process serving broken requests instead of restarting. Both
processes now log and then exit(1); restart: unless-stopped is added
to both services so Docker actually brings them back up.

Also: harden the logger against JSON.stringify throwing on
non-serializable meta, log aborted (closed-before-finished) requests
in the API access log, and stop the Next.js proxy from logging the
Docker healthcheck's request to "/" every few seconds so real
navigation events aren't drowned out.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

compose.yaml

@@ -13,6 +13,7 @@ services:
       CHOKIDAR_USEPOLLING: "true"
       LOG_LEVEL: "${LOG_LEVEL:-info}"
     init: true
+    restart: unless-stopped
     logging:
       driver: json-file
       options:
@@ -53,6 +54,7 @@ services:
       NEXT_TELEMETRY_DISABLED: "1"
       LOG_LEVEL: "${LOG_LEVEL:-info}"
     init: true
+    restart: unless-stopped
     logging:
       driver: json-file
       options:

docs/deployment.md

@@ -58,6 +58,15 @@ mit Laufzeit und Speicherverbrauch – nützlich, um Speicherlecks oder Hänger
 einem 502 über einen längeren Zeitraum nachzuvollziehen. Für die Detailsuche
 `LOG_LEVEL=debug` setzen; das protokolliert zusätzlich den Start jeder
 API-Anfrage und macht damit hängende (nie abgeschlossene) Requests sichtbar.
+Ein `close`-Ereignis ohne vorheriges `finish` wird als `request aborted before
+response finished` (`warn`) geloggt und zeigt damit vom Client oder einem
+vorgeschalteten Proxy abgebrochene Verbindungen.
+
+Eine unbehandelte Exception oder Promise-Rejection wird geloggt und beendet
+den jeweiligen Prozess anschließend bewusst (`process.exit(1)`), statt in
+einem unbekannten Zustand weiterzulaufen. Beide Dienste laufen deshalb mit
+`restart: unless-stopped`, damit Docker sie danach automatisch neu startet;
+ohne diese Policy würde ein Crash den Dienst dauerhaft unerreichbar lassen.
 
 ## Voraussetzungen für ein späteres Produktionssetup
 

src/instrumentation-node.ts

@@ -7,11 +7,13 @@ export function registerNodeInstrumentation() {
   logger.info("web server starting", { pid: process.pid });
 
   process.on("uncaughtException", (error) => {
-    logger.error("uncaught exception", toErrorMeta(error));
+    logger.error("uncaught exception, exiting", toErrorMeta(error));
+    process.exit(1);
   });
 
   process.on("unhandledRejection", (reason) => {
-    logger.error("unhandled rejection", toErrorMeta(reason));
+    logger.error("unhandled rejection, exiting", toErrorMeta(reason));
+    process.exit(1);
   });
 
   setInterval(() => {

src/proxy.ts

@@ -5,10 +5,14 @@ import { createLogger } from "./shared/logging/logger";
 const logger = createLogger("web:navigation");
 
 export function proxy(request: NextRequest) {
+  // The Docker healthcheck hits "/" every few seconds with no User-Agent
+  // header; skip it so real navigation isn't drowned out in the logs.
+  if (request.headers.get("user-agent")) {
     logger.info("page request", {
       method: request.method,
       path: request.nextUrl.pathname,
     });
+  }
   return NextResponse.next();
 }
 

src/server/index.ts

@@ -31,6 +31,15 @@ app.use((req, res, next) => {
     else if (res.statusCode >= 400) logger.warn("request completed", meta);
     else logger.info("request completed", meta);
   });
+  res.on("close", () => {
+    if (!res.writableEnded) {
+      logger.warn("request aborted before response finished", {
+        method: req.method,
+        path: req.originalUrl,
+        durationMs: Date.now() - startedAt,
+      });
+    }
+  });
   next();
 });
 
@@ -46,11 +55,13 @@ app.use("/api/project-devices", projectDeviceRouter);
 app.use(errorMiddleware);
 
 process.on("uncaughtException", (error) => {
-  logger.error("uncaught exception", toErrorMeta(error));
+  logger.error("uncaught exception, exiting", toErrorMeta(error));
+  process.exit(1);
 });
 
 process.on("unhandledRejection", (reason) => {
-  logger.error("unhandled rejection", toErrorMeta(reason));
+  logger.error("unhandled rejection, exiting", toErrorMeta(reason));
+  process.exit(1);
 });
 
 process.on("SIGTERM", () => logger.info("received SIGTERM"));

src/shared/logging/logger.ts

@@ -47,13 +47,19 @@ export function createLogger(
     if (LEVEL_SEVERITY[level] > LEVEL_SEVERITY[threshold]) {
       return;
     }
-    const line = JSON.stringify({
+    const timestamp = new Date().toISOString();
-      timestamp: new Date().toISOString(),
+    let line: string;
+    try {
+      line = JSON.stringify({ timestamp, level, scope, message, ...meta });
+    } catch {
+      line = JSON.stringify({
+        timestamp,
         level,
         scope,
         message,
-      ...meta,
+        logError: "failed to serialize log metadata",
       });
+    }
     if (level === "error" || level === "warn") {
       console.error(line);
     } else {