feat: add a secondary port with admin endpoints

The first endpoint included is for metrics using the prometheus
exposition format.

Author: darora

package-lock.json

@@ -35,6 +35,7 @@
   },
   "dependencies": {
     "@sinclair/typebox": "^0.23.4",
+    "fastify-metrics": "^8.0.0",
     "pg": "^8.7.1",
     "pg-format": "^1.0.4",
     "pgsql-parser": "^13.3.0",

package.json

@@ -0,0 +1,13 @@
+import fastify, { FastifyInstance, FastifyServerOptions } from 'fastify'
+
+import _default = require('fastify-metrics')
+
+export function build(opts: FastifyServerOptions = {}): FastifyInstance {
+  const app = fastify(opts)
+  app.register(_default, {
+    endpoint: '/metrics',
+    enableRouteMetrics: false,
+    blacklist: ['nodejs_version_info', 'process_start_time_seconds'],
+  })
+  return app
+}

src/server/admin-app.ts

@@ -4,6 +4,7 @@ import routes from './routes'
 import { extractRequestForLogging } from './utils'
 import pino from 'pino'
 import pkg from '../../package.json'
+import { build as buildAdminApp } from './admin-app'
 
 const logger = pino({
   formatters: {
@@ -57,6 +58,11 @@ if (PG_META_EXPORT_DOCS) {
   app.ready(() => {
     app.listen(PG_META_PORT, '0.0.0.0', () => {
       app.log.info(`App started on port ${PG_META_PORT}`)
+      const adminApp = buildAdminApp({ logger })
+      const adminPort = PG_META_PORT + 1
+      adminApp.listen(adminPort, '0.0.0.0', () => {
+        adminApp.log.info(`Admin App started on port ${adminPort}`)
+      })
     })
   })
 }