initial work on new pool

brianc · brianc · commit 971eb5d1ef84 · 2013-02-15T16:13:28.000-06:00
diff --git a/lib/pool.js b/lib/pool.js
@@ -0,0 +1,78 @@
+var defaults = require(__dirname + '/defaults');
+var genericPool = require('generic-pool');
+
+//takes the same config structure as client
+var createPool = function(config) {
+  config = config || {};
+  var name = JSON.stringify(config);
+  var pool = createPool.all[name];
+  if(pool) {
+    return pool;
+  }
+  pool = genericPool.Pool({
+    name: name,
+    max: defaults.poolSize,
+    create: function(cb) {
+      var client = new createPool.Client(config);
+      client.connect(function(err) {
+        return cb(err, client);
+      });
+    },
+    destroy: function(client) {
+      client.end();
+    }
+  });
+  createPool.all[name] = pool;
+  pool.connect = function(cb) {
+    pool.acquire(function(err, client) {
+      //TODO: on connection error should we remove this client automatically?
+      if(err) {
+        return cb(err);
+      }
+      if(cb.length > 2) {
+        return newConnect(pool, client, cb);
+      }
+      return oldConnect(pool, client, cb);
+    });
+  };
+  return pool;
+}
+
+//the old connect method of the pool
+//would automatically subscribe to the 'drain'
+//event and automatically return the client to
+//the pool once 'drain' fired once.  This caused
+//a bunch of problems, but for backwards compatibility
+//we're leaving it in
+var alarmDuration = 1000;
+var errorMessage = ['A client has been checked out from the pool for longer than ' + alarmDuration + ' ms.',
+'You might have a leak!',
+'You should use the following new way to check out clients','pg.connect(function(err, client, done)) {',
+'  //do something',
+'  done();  //call done() to signal you are finished with the client',
+'}'].join(require('os').EOL);
+var oldConnect = function(pool, client, cb) {
+  var tid = setTimeout(function() {
+    console.error(errorMessage);
+  }, alarmDuration);
+  var release = function() {
+    clearTimeout(tid);
+    pool.release(client);
+  };
+  client.once('drain', release);
+  cb(null, client);
+};
+
+var newConnect = function(pool, client, cb) {
+  cb(null, client, function() {
+    pool.release(client);
+  });
+};
+
+//list of all created pools
+createPool.all = {};
+
+//reference to client constructor
+createPool.Client = require(__dirname + '/client');
+
+module.exports = createPool;
diff --git a/test/unit/pool/basic-tests.js b/test/unit/pool/basic-tests.js
@@ -0,0 +1,103 @@
+var util = require('util');
+var EventEmitter = require('events').EventEmitter;
+
+var libDir = __dirname + '/../../../lib';
+var defaults = require(libDir + '/defaults');
+var pool = require(libDir + '/pool');
+var poolId = 0;
+
+require(__dirname + '/../../test-helper');
+
+var FakeClient = function() {
+  EventEmitter.call(this);
+}
+
+util.inherits(FakeClient, EventEmitter);
+
+FakeClient.prototype.connect = function(cb) {
+  process.nextTick(cb);
+}
+
+FakeClient.prototype.end = function() {
+  
+}
+
+//Hangs the event loop until 'end' is called on client
+var HangingClient = function(config) {
+  EventEmitter.call(this);
+  this.config = config;
+}
+
+util.inherits(HangingClient, EventEmitter);
+
+HangingClient.prototype.connect = function(cb) {
+  this.intervalId = setInterval(function() {
+    console.log('hung client...');
+  }, 1000);
+  process.nextTick(cb);
+}
+
+HangingClient.prototype.end = function() {
+  clearInterval(this.intervalId);
+}
+
+pool.Client = FakeClient;
+
+test('no pools exist', function() {
+  assert.empty(Object.keys(pool.all));
+});
+
+test('pool creates pool on miss', function() {
+  var p = pool();
+  assert.ok(p);
+  assert.equal(Object.keys(pool.all).length, 1);
+  var p2 = pool();
+  assert.equal(p, p2);
+  assert.equal(Object.keys(pool.all).length, 1);
+  var p3 = pool("pg://postgres:password@localhost:5432/postgres");
+  assert.notEqual(p, p3);
+  assert.equal(Object.keys(pool.all).length, 2);
+});
+
+test('pool follows default limits', function() {
+  var p = pool(poolId++);
+  for(var i = 0; i < 100; i++) {
+    p.acquire(function(err, client) {
+    });
+  }
+  assert.equal(p.getPoolSize(), defaults.poolSize);
+});
+
+test('pool#connect with 2 parameters (legacy, for backwards compat)', function() {
+  var p = pool(poolId++);
+  p.connect(assert.success(function(client) {
+    assert.ok(client);
+    assert.equal(p.availableObjectsCount(), 0);
+    assert.equal(p.getPoolSize(), 1);
+    client.emit('drain');
+    assert.equal(p.availableObjectsCount(), 1);
+    assert.equal(p.getPoolSize(), 1);
+    p.destroyAllNow();
+  }));
+});
+
+test('pool#connect with 3 parameters', function() {
+  var p = pool(poolId++);
+  var tid = setTimeout(function() {
+    throw new Error("Connection callback was never called");
+  }, 100);
+  p.connect(function(err, client, done) {
+    clearTimeout(tid);
+    assert.equal(err, null);
+    assert.ok(client);
+    assert.equal(p.availableObjectsCount(), 0);
+    assert.equal(p.getPoolSize(), 1);
+    client.emit('drain');
+    assert.equal(p.availableObjectsCount(), 0);
+    assert.equal(p.getPoolSize(), 1);
+    done();
+    assert.equal(p.availableObjectsCount(), 1);
+    assert.equal(p.getPoolSize(), 1);
+    p.destroyAllNow();
+  });
+});
