added user metrics

README.md

@@ -21,8 +21,8 @@ Backend for movie-web
   - [ ] consume provider metrics
   - [ ] DELETE user - should delete all associated data
  - [ ] prometheus metrics
-  - [ ] requests
-  - [ ] user count
+  - [X] requests
+  - [X] user count
   - [ ] provider metrics
  - [ ] ratelimits (stored in redis)
  - [X] switch to pnpm

src/main.ts

@@ -1,4 +1,5 @@
-import { setupFastify } from '@/modules/fastify';
+import { setupFastify, startFastify } from '@/modules/fastify';
+import { setupMetrics } from '@/modules/metrics';
 import { setupMikroORM } from '@/modules/mikro';
 import { scopedLogger } from '@/services/logger';
 
@@ -9,8 +10,11 @@ async function bootstrap(): Promise<void> {
     evt: 'setup',
   });
 
+  const app = await setupFastify();
   await setupMikroORM();
-  await setupFastify();
+  await setupMetrics(app);
+
+  await startFastify(app);
 
   log.info(`App setup, ready to accept connections`, {
     evt: 'success',

src/modules/fastify/index.ts

@@ -72,9 +72,14 @@ export async function setupFastify(): Promise<FastifyInstance> {
     },
   );
 
+  if (!exportedApp) throw new Error('no app to export in fastify');
+  return exportedApp;
+}
+
+export function startFastify(app: FastifyInstance) {
   // listen to port
   log.info(`listening to port`, { evt: 'setup-listen' });
-  return new Promise((resolve) => {
+  return new Promise<void>((resolve) => {
     app.listen(
       {
         port: conf.server.port,
@@ -91,7 +96,7 @@ export async function setupFastify(): Promise<FastifyInstance> {
         log.info(`fastify setup successfully`, {
           evt: 'setup-success',
         });
-        resolve(exportedApp as FastifyInstance);
+        resolve();
       },
     );
   });

src/modules/fastify/routes.ts

@@ -9,11 +9,8 @@ import { userProgressRouter } from '@/routes/users/progress';
 import { userSessionsRouter } from '@/routes/users/sessions';
 import { userSettingsRouter } from '@/routes/users/settings';
 import { FastifyInstance } from 'fastify';
-import metricsPlugin from 'fastify-metrics';
 
 export async function setupRoutes(app: FastifyInstance) {
-  await app.register(metricsPlugin, { endpoint: '/metrics' });
-
   await app.register(manageAuthRouter.register);
   await app.register(loginAuthRouter.register);
   await app.register(userSessionsRouter.register);

src/modules/metrics/index.ts

@@ -0,0 +1,39 @@
+import { getORM } from '@/modules/mikro';
+import { FastifyInstance } from 'fastify';
+import { Counter } from 'prom-client';
+import metricsPlugin from 'fastify-metrics';
+import { updateMetrics } from '@/modules/metrics/update';
+import { scopedLogger } from '@/services/logger';
+
+const log = scopedLogger('metrics');
+
+export type Metrics = {
+  user: Counter<'namespace'>;
+};
+
+let metrics: null | Metrics = null;
+
+export function getMetrics() {
+  if (!metrics) throw new Error('metrics not initialized');
+  return metrics;
+}
+
+export async function setupMetrics(app: FastifyInstance) {
+  log.info(`Setting up metrics...`, { evt: 'start' });
+
+  await app.register(metricsPlugin, { endpoint: '/metrics' });
+
+  metrics = {
+    user: new Counter({
+      name: 'user_count',
+      help: 'user_help',
+      labelNames: ['namespace'],
+    }),
+  };
+
+  const orm = getORM();
+  const em = orm.em.fork();
+  log.info(`Syncing up metrics...`, { evt: 'sync' });
+  await updateMetrics(em, metrics);
+  log.info(`Metrics initialized!`, { evt: 'end' });
+}

src/modules/metrics/update.ts

@@ -0,0 +1,22 @@
+import { User } from '@/db/models/User';
+import { Metrics } from '@/modules/metrics';
+import { EntityManager } from '@mikro-orm/postgresql';
+
+export async function updateMetrics(em: EntityManager, metrics: Metrics) {
+  const users = await em
+    .createQueryBuilder(User)
+    .groupBy('namespace')
+    .count()
+    .select(['namespace', 'count'])
+    .execute<
+      {
+        namespace: string;
+        count: string;
+      }[]
+    >();
+
+  metrics.user.reset();
+  users.forEach((v) => {
+    metrics?.user.inc({ namespace: v.namespace }, Number(v.count));
+  });
+}

src/routes/auth/manage.ts

@@ -1,5 +1,6 @@
 import { formatSession } from '@/db/models/Session';
 import { User, formatUser } from '@/db/models/User';
+import { getMetrics } from '@/modules/metrics';
 import { assertCaptcha } from '@/services/captcha';
 import { handle } from '@/services/handler';
 import { makeRouter } from '@/services/router';
@@ -37,6 +38,7 @@ export const manageAuthRouter = makeRouter((app) => {
       );
 
       await em.persistAndFlush([user, session]);
+      getMetrics().user.inc({ namespace: body.namespace }, 1);
 
       return {
         user: formatUser(user),