fix: log idle client errors instead of crashing

index.js

@@ -88,6 +88,19 @@ function fastifyPostgres (fastify, options, next) {
   delete options.name
 
   const pool = new pg.Pool(options)
+  // pg-pool re-emits idle client errors here; unhandled, it crashes the process
+  pool.on('error', () => {})
+  // fires for idle and checked-out clients, so log only here
+  pool.on('connect', (client) => {
+    let errored = false
+    client.on('error', (err) => {
+      // a dropped connection emits follow-ups like 'Connection terminated unexpectedly'; like pg-pool, log only the first
+      if (errored) return
+      errored = true
+      fastify.log.error({ err, name }, 'pg client error')
+    })
+  })
+
   const db = {
     connect: pool.connect.bind(pool),
     pool,

test/initialization.test.js

@@ -237,3 +237,81 @@ test('const result = await fastify.pg and a fastify.pg custom namespace should e
   t.assert.deepStrictEqual(result.rowCount, 1)
   t.assert.deepStrictEqual(resultOne.rowCount, 1)
 })
+
+test('Should log instead of crashing when an idle client errors', { timeout: 10000 }, async (t) => {
+  t.plan(4)
+
+  const errorLogs = []
+  const stream = {
+    write (line) {
+      const log = JSON.parse(line)
+      if (log.level === 50) errorLogs.push(log)
+    }
+  }
+
+  const fastify = Fastify({ logger: { stream } })
+  t.after(() => fastify.close())
+
+  await fastify.register(fastifyPostgres, {
+    connectionString
+  })
+  await fastify.ready()
+
+  const client = await fastify.pg.connect()
+  const { rows } = await client.query('SELECT pg_backend_pid() AS pid')
+  const ended = new Promise((resolve) => client.once('end', resolve))
+  client.release()
+  t.assert.strictEqual(fastify.pg.pool.idleCount, 1)
+
+  const admin = new fastify.pg.Client({ connectionString })
+  await admin.connect()
+  await admin.query('SELECT pg_terminate_backend($1)', [rows[0].pid])
+  await admin.end()
+  await ended
+
+  t.assert.strictEqual(errorLogs.length, 1)
+  t.assert.strictEqual(errorLogs[0].err.code, '57P01')
+
+  const result = await fastify.pg.query('SELECT 1 AS one')
+  t.assert.strictEqual(result.rows[0].one, 1)
+})
+
+test('Should log instead of crashing when a checked-out client errors', { timeout: 10000 }, async (t) => {
+  t.plan(4)
+
+  const errorLogs = []
+  const stream = {
+    write (line) {
+      const log = JSON.parse(line)
+      if (log.level === 50) errorLogs.push(log)
+    }
+  }
+
+  const fastify = Fastify({ logger: { stream } })
+
+  await fastify.register(fastifyPostgres, {
+    connectionString
+  })
+  await fastify.ready()
+
+  const client = await fastify.pg.connect()
+  t.after(() => {
+    client.release()
+    return fastify.close()
+  })
+  const { rows } = await client.query('SELECT pg_backend_pid() AS pid')
+  const ended = new Promise((resolve) => client.once('end', resolve))
+
+  const admin = new fastify.pg.Client({ connectionString })
+  await admin.connect()
+  await admin.query('SELECT pg_terminate_backend($1)', [rows[0].pid])
+  await admin.end()
+  await ended
+
+  t.assert.strictEqual(errorLogs.length, 1)
+  t.assert.strictEqual(errorLogs[0].err.code, '57P01')
+  await t.assert.rejects(client.query('SELECT 1'), /not queryable/)
+
+  const result = await fastify.pg.query('SELECT 1 AS one')
+  t.assert.strictEqual(result.rows[0].one, 1)
+})