Add acquireTimeout pool option

closes #821
closes #854

Author: dougwilson

Changes.md

@@ -7,6 +7,7 @@ you spot any mistakes.
 ## HEAD
 
 * Add code `POOL_NOEXIST` in PoolCluster error #846
+* Add `acquireTimeout` pool option to specify a timeout for acquiring a connection #821 #854
 * Add `timeout` option to all sequences #855 #863
 * Default `connectTimeout` to 10 seconds
 * Fix domain binding with `conn.connect`

Readme.md

@@ -328,6 +328,9 @@ Pools accept all the same options as a connection. When creating a new
 connection, the options are simply passed to the connection constructor. In
 addition to those options pools accept a few extras:
 
+* `acquireTimeout`: The milliseconds before a timeout occurs during the connection
+  acquisition. This is slightly different from `connectTimeout`, because acquiring
+  a pool connection does not always involve making a connection. (Default: 10 seconds)
 * `waitForConnections`: Determines the pool's action when no connections are
   available and the limit has been reached. If `true`, the pool will queue the
   connection request and call it when one becomes available. If `false`, the

lib/Pool.js

@@ -75,7 +75,7 @@ Pool.prototype.acquireConnection = function acquireConnection(connection, cb) {
   var pool = this;
 
   connection._pool = null;
-  connection.ping(function(err){
+  connection.ping({timeout: this.config.acquireTimeout}, function(err) {
     if (!err) {
       connection._pool = pool;
       cb(null, connection);

lib/PoolConfig.js

@@ -7,6 +7,9 @@ function PoolConfig(options) {
     options = ConnectionConfig.parseUrl(options);
   }
 
+  this.acquireTimeout     = (options.acquireTimeout === undefined)
+    ? 10 * 1000
+    : Number(options.acquireTimeout);
   this.connectionConfig   = new ConnectionConfig(options);
   this.waitForConnections = (options.waitForConnections === undefined)
     ? true

test/unit/pool/test-acquire-timeout.js

@@ -0,0 +1,60 @@
+var assert = require('assert');
+var common = require('../../common');
+var pool   = common.createPool({
+  acquireTimeout  : 100,
+  connectionLimit : 1,
+  port            : common.fakeServerPort
+});
+var server  = common.createFakeServer();
+var Packets = require(common.lib + '/protocol/packets');
+
+var fail       = false;
+var seq        = 0;
+var serverConn = null;
+var tid        = 0;
+
+server.listen(common.fakeServerPort, function (err) {
+  assert.ifError(err);
+
+  pool.getConnection(function (err, conn) {
+    assert.ifError(err);
+    assert.equal(conn.threadId, 1);
+    conn.release();
+
+    // lag the next ping
+    fail = true;
+
+    pool.getConnection(function(err, conn){
+      assert.ifError(err);
+      assert.equal(++seq, 1);
+      assert.equal(conn.threadId, 2);
+      assert.equal(fail, false);
+      conn.ping(function(err){
+        assert.ifError(err);
+        conn.release();
+      });
+    });
+
+    pool.getConnection(function(err, conn){
+      assert.ifError(err);
+      assert.equal(++seq, 2);
+      assert.equal(conn.threadId, 2);
+      server.destroy();
+    });
+  });
+});
+
+server.on('connection', function(incomingConnection) {
+  serverConn = incomingConnection;
+  incomingConnection.handshake({
+    threadId: ++tid
+  });
+  incomingConnection.on('ping', function() {
+    if (!fail) {
+      this._sendPacket(new Packets.OkPacket());
+      this._parser.resetPacketNumber();
+    }
+
+    fail = false;
+  });
+});

test/unit/test-PoolConfig.js

@@ -41,3 +41,35 @@ test('PoolConfig#Constructor', {
     assert.equal(config.connectionLimit, 2);
   },
 });
+
+test('PoolConfig#Constructor.acquireTimeout', {
+  'defaults to 10 seconds': function() {
+    var config = new PoolConfig({});
+
+    assert.equal(config.acquireTimeout, (10 * 1000));
+  },
+
+  'undefined uses default': function() {
+    var config = new PoolConfig({
+      acquireTimeout: undefined
+    });
+
+    assert.equal(config.acquireTimeout, (10 * 1000));
+  },
+
+  'can set to 0': function() {
+    var config = new PoolConfig({
+      acquireTimeout: 0
+    });
+
+    assert.equal(config.acquireTimeout, 0);
+  },
+
+  'can set to custom value': function() {
+    var config = new PoolConfig({
+      acquireTimeout: 10000
+    });
+
+    assert.equal(config.acquireTimeout, 10000);
+  },
+});