Connection lifetime

README.md

@@ -53,6 +53,7 @@ const sql = postgres('postgres://username:password@host:port/database', {
   password        : '',         // Password of database user
   ssl             : false,      // true, prefer, require, tls.connect options
   max             : 10,         // Max number of connections
+  lifetime        : -1,         // Max connection lifetime in seconds (default: forever)
   idle_timeout    : 0,          // Idle connection timeout in seconds
   connect_timeout : 30,         // Connect timeout in seconds
   no_prepare      : false,      // No automatic creation of prepared statements

lib/connection.js

@@ -16,6 +16,7 @@ function Connection(options = {}) {
     transform,
     idle_timeout,
     connect_timeout,
+    lifetime,
     onnotify,
     onnotice,
     onclose,
@@ -31,6 +32,9 @@ function Connection(options = {}) {
   let ready = false
   let write = false
   let next = false
+  let readyAt
+  let endingGracefully
+  let endedGracefully
   let statements = {}
   let connect_timer
 
@@ -46,7 +50,7 @@ function Connection(options = {}) {
     cleanup
   })
 
-  const connection = { send, end, destroy, socket }
+  const connection = { send, hasExpired, endGracefully, end, destroy, socket }
 
   const backend = Backend({
     onparse,
@@ -105,6 +109,21 @@ function Connection(options = {}) {
     ).catch(onerror)
   }
 
+  function hasExpired() {
+    return lifetime > 0 && ((new Date() - readyAt) > (lifetime * 1000))
+  }
+
+  function endGracefully() {
+    if (!endingGracefully) {
+      endingGracefully = new Promise((resolve) => {
+        endedGracefully = () => resolve()
+      })
+    }
+    tryGracefulEnd()
+
+    return endingGracefully
+  }
+
   function end() {
     clearTimeout(timer)
     const promise = new Promise((resolve) => {
@@ -207,6 +226,11 @@ function Connection(options = {}) {
       clearTimeout(timer)
       timer = setTimeout(socket.end, idle_timeout * 1000)
     }
+    endingGracefully && tryGracefulEnd()
+  }
+
+  function tryGracefulEnd() {
+    !backend.query && queries.length === 0 && end().then(destroy).then(endedGracefully)
   }
 
   function onready(err) {
@@ -243,6 +267,10 @@ function Connection(options = {}) {
       messages.forEach(x => socket.write(x))
       messages = []
       open = true
+
+      if (lifetime > -1) {
+        readyAt = new Date()
+      }
     }
 
     backend.query = queries.shift()

lib/index.js

@@ -228,7 +228,21 @@ function Postgres(a, b) {
   }
 
   function getConnection(reserve) {
-    const connection = slots ? createConnection(options) : connections.shift()
+    let connection
+    while (1) {
+      connection = slots ? createConnection(options) : connections.shift()
+      if (!connection || !connection.hasExpired())
+        break
+
+      // has expired
+      const conn = connection // local scope closure
+      conn.endGracefully().then(() => {
+        slots++
+        // remove connection from all
+        all.splice(all.findIndex(x => x === conn), 1)
+      })
+    } 
+
     !reserve && connection && connections.push(connection)
     return connection
   }
@@ -634,6 +648,7 @@ function parseOptions(a, b) {
     user            : user,
     pass            : o.pass || o.password || auth[1] || env.PGPASSWORD || '',
     max             : o.max || url.query.max || 10,
+    lifetime        : o.lifetime || -1,
     types           : o.types || {},
     ssl             : o.ssl || parseSSL(url.query.sslmode || url.query.ssl) || false,
     idle_timeout    : o.idle_timeout || url.query.idle_timeout || env.PGIDLE_TIMEOUT || warn(o.timeout),

tests/index.js

@@ -1494,3 +1494,49 @@ t('multiple queries before connect', async() => {
     xs.map(x => x[0].x).join()
   ]
 })
+
+t('Connection with no lifetime', async() => {
+  const sql = postgres(options)
+
+  let result = await sql`select 1`
+  let startPid = result.state.pid
+
+  await delay(100);
+
+  result = await sql`select 1`
+  let pid = result.state.pid
+
+  return [true, pid == startPid]
+})
+
+t('Connection lifetime', async() => {
+  const sql = postgres({...options, lifetime: 0.050})
+
+  let result = await sql`select 1`
+  let startPid = result.state.pid
+
+  await delay(100);
+
+  result = await sql`select 1`
+  let pid = result.state.pid
+
+  return [true, pid != startPid]
+})
+
+t('Connection lifetime transaction', async() => {
+  const sql = postgres({...options, lifetime: 0.050})
+
+  let success
+
+  await sql.begin(async (sql) => {
+    await delay(100);
+    try {
+      await sql`select 1`
+      success = true
+    } catch (err) {
+      success = false
+    }
+  })
+
+  return [true, success]
+})

types/index.d.ts

@@ -28,6 +28,8 @@ interface BaseOptions<T extends JSToPostgresTypeMap> {
   ssl: 'require' | 'prefer' | boolean | object;
   /** Max number of connections */
   max: number;
+  /** Connection lifetime in seconds */
+  lifetime: number | undefined;
   /** Idle connection timeout in seconds */
   idle_timeout: number | undefined;
   /** Connect timeout in seconds */