docs: how to see your logs in Kibana

README.md

@@ -7,6 +7,7 @@ Express 5 + TypeScript backend generated from `nholtware/service-template-expres
 - `GET /healthz` liveness, always 200 once listening
 - `GET /readyz` readiness: Postgres `SELECT 1` and Redis `PING` for whichever of `DATABASE_URL` / `REDIS_URL` are set; 503 + JSON reason otherwise
 - `GET /` service name, version (git sha), pod, a `service_info` row, Redis hit counter
+- `GET /log-demo?msg=...` logs `{ demo: true, text }` with message `log-demo` (logging-pipeline demo; delete when you don't need it)
 
 ## Local dev
 
@@ -20,6 +21,20 @@ Env is validated at boot (`src/lib/config.ts`): `PORT`, `SERVICE_NAME` (required
 Migrations: SQL files in `migrations/`, applied with `npm run migrate`.
 Logs: one JSON object per line on stdout (`level,time,msg,service,version`, plus `req.*`/`res.statusCode`/`responseTime` per request).
 
+## Seeing your logs
+
+Every container's stdout is shipped to Elasticsearch by Fluent Bit; nothing to configure per service.
+
+1. Open Kibana: http://kibana.192.168.1.83.nip.io, user `elastic`, password from
+   `kubectl get secret -n logging logging-es-elastic-user -o jsonpath='{.data.elastic}' | base64 -d`.
+2. **Discover**, data view `kube-*` (the default).
+3. Query with KQL, e.g. `service:"${REPO_NAME}" and demo:true`, or `service:"${REPO_NAME}" and level:"error"`.
+
+Any field you pass to the logger becomes a queryable field:
+`req.log.info({ orderId }, "order placed")` → KQL `orderId:123`. The message string always
+overrides a `msg` key in the object, so don't name a field `msg`. Lines show up within ~10 s;
+retention is 14 days.
+
 ## Using this template
 
 1. **Generate** a repo from this template in Forgejo (public). The repo name is substituted into `package.json`, this README, `.env.example`, and the first migration (CI derives the app name from the repo name itself).

src/app.test.ts

@@ -67,3 +67,26 @@ describe("routes", () => {
     expect(b.headers["x-request-id"]).toMatch(/^[0-9a-f-]{36}$/);
   });
 });
+
+describe("log-demo", () => {
+  it("logs one JSON line with demo fields and the request id", async () => {
+    const lines: Record<string, unknown>[] = [];
+    const captured = pino(
+      { base: { service: "test-svc" } },
+      { write: (l: string) => lines.push(JSON.parse(l)) },
+    );
+    const app = createApp({ config: parseConfig(base), logger: captured });
+    const res = await request(app)
+      .get("/log-demo?msg=hello")
+      .set("X-Request-Id", "rid-demo");
+    expect(res.status).toBe(200);
+    expect(res.body).toMatchObject({ logged: true, text: "hello" });
+    const line = lines.find((l) => l.msg === "log-demo");
+    expect(line).toMatchObject({
+      service: "test-svc",
+      demo: true,
+      text: "hello",
+      req: { id: "rid-demo" },
+    });
+  });
+});

src/app.ts

@@ -6,6 +6,7 @@ import type { Config } from "./lib/config.js";
 import type { Db } from "./lib/db.js";
 import type { Cache } from "./lib/redis.js";
 import { healthRouter } from "./routes/health.js";
+import { logDemoRouter } from "./routes/log-demo.js";
 import { rootRouter } from "./routes/root.js";
 
 export interface Deps {
@@ -43,6 +44,7 @@ export function createApp({ config, logger, db, cache }: Deps) {
 
   app.use(healthRouter({ db, cache }));
   app.use(rootRouter({ config, db, cache }));
+  app.use(logDemoRouter());
 
   // Express identifies error handlers by arity; keep all four args.
   // eslint-disable-next-line @typescript-eslint/no-unused-vars

src/routes/log-demo.ts

@@ -0,0 +1,17 @@
+import { Router } from "express";
+
+// Developer-story demo for the logging pipeline: every field in the first
+// argument to req.log.* becomes a queryable field in Kibana (data view kube-*).
+// The message string always wins over a `msg` key in the object, so the
+// caller's text goes in `text`.
+export function logDemoRouter(): Router {
+  const router = Router();
+
+  router.get("/log-demo", (req, res) => {
+    const text = typeof req.query.msg === "string" ? req.query.msg : "";
+    req.log.info({ demo: true, text }, "log-demo");
+    res.json({ logged: true, text, requestId: req.id });
+  });
+
+  return router;
+}