Merge pull request #345 from innofluence/read-replication

Read replication for Mysql (experimental)

lib/dialects/mysql/connector-manager.js

@@ -13,20 +13,95 @@ module.exports = (function() {
     this.queue = []
     this.activeQueue = []
     this.maxConcurrentQueries = (this.config.maxConcurrentQueries || 50)
-    this.poolCfg = this.config.pool
+    this.poolCfg = Utils._.defaults(this.config.pool, {
+      maxConnections: 10,
+      minConnections: 0,
+      maxIdleTime: 1000
+    });
     this.pendingQueries = 0;
+    this.useReplicaton = !!config.replication;
     this.useQueue = config.queue !== undefined ? config.queue : true;
 
     var self = this
 
-    if (this.poolCfg) {
-      //the user has requested pooling, so create our connection pool
-      if (!this.poolCfg.maxConnections) {
-        this.poolCfg.maxConnections = 10
+    if (this.useReplicaton) {
+      var reads = 0, 
+        writes = 0;
+
+      // Init configs with options from config if not present
+      for (var i in config.replication.read) {
+        config.replication.read[i] = Utils._.defaults(config.replication.read[i], {
+          host: this.config.host,
+          port: this.config.port,
+          username: this.config.username,
+          password: this.config.password,
+          database: this.config.database
+        });
+      }
+      config.replication.write = Utils._.defaults(config.replication.write, {
+        host: this.config.host,
+        port: this.config.port,
+        username: this.config.username,
+        password: this.config.password,
+        database: this.config.database
+      });
+
+      // I'll make my own pool, with blackjack and hookers!
+      this.pool = {
+        release: function (client) {
+          if (client.queryType == 'read') {
+            return this.read.release(client);
+          } else {
+            return this.write.release(client);
           }
-      if (!this.poolCfg.minConnections) {
-        this.poolCfg.minConnections = 0
+        },
+        acquire: function (callback, priority, queryType) {
+          if (queryType == 'SELECT') {
+            this.read.acquire(callback, priority);
+          } else {
+            this.write.acquire(callback, priority);
           }
+        },
+        drain: function () {
+          this.read.drain();
+          this.write.drain();
+        },
+        read: Pooling.Pool({
+          name: 'sequelize-read',
+          create: function (done) {
+            if (reads >= self.config.replication.read.length) reads = 0;
+            var config = self.config.replication.read[reads++];
+
+            connect.call(self, function (err, connection) {
+              connection.queryType = 'read'
+              done(null, connection)
+            }, config);
+          },
+          destroy: function(client) {
+            disconnect.call(self, client)
+          },
+          max: self.poolCfg.maxConnections,
+          min: self.poolCfg.minConnections,
+          idleTimeoutMillis: self.poolCfg.maxIdleTime
+        }),
+        write: Pooling.Pool({
+          name: 'sequelize-write',
+          create: function (done) {
+            connect.call(self, function (err, connection) {
+              connection.queryType = 'write'
+              done(null, connection)
+            }, self.config.replication.write);
+          },
+          destroy: function(client) {
+            disconnect.call(self, client)
+          },
+          max: self.poolCfg.maxConnections,
+          min: self.poolCfg.minConnections,
+          idleTimeoutMillis: self.poolCfg.maxIdleTime
+        })
+      };
+    } else if (this.poolCfg) {
+      //the user has requested pooling, so create our connection pool
       this.pool = Pooling.Pool({
         name: 'sequelize-mysql',
         create: function (done) {
@@ -66,7 +141,7 @@ module.exports = (function() {
         sql: sql
       };
 
-      enqueue.call(this, queueItem);
+      enqueue.call(this, queueItem, options);
       return queueItem.query;
     }
 
@@ -93,7 +168,7 @@ module.exports = (function() {
         query.client = client;
         query.run(sql);
         return;
-      });
+      }, undefined, options.type);
     }
 
     return query;
@@ -146,13 +221,14 @@ module.exports = (function() {
     })
   }
 
-  var connect = function(done) {
+  var connect = function(done, config) {
+    config = config || this.config
     var connection = mysql.createConnection({
-      host: this.config.host,
-      port: this.config.port,
-      user: this.config.username,
-      password: this.config.password,
-      database: this.config.database
+      host: config.host,
+      port: config.port,
+      user: config.username,
+      password: config.password,
+      database: config.database
     })
     // client.setMaxListeners(self.maxConcurrentQueries)
     this.isConnecting = false
@@ -160,7 +236,8 @@ module.exports = (function() {
     done(null, connection)
   }
 
-  var enqueue = function(queueItem) {
+  var enqueue = function(queueItem, options) {
+    options = options || {}
     if(this.activeQueue.length < this.maxConcurrentQueries) {
       this.activeQueue.push(queueItem)
       if (this.pool) {
@@ -176,7 +253,7 @@ module.exports = (function() {
           queueItem.client = client
           execQueueItem.call(self, queueItem)
           return
-        })
+        }, undefined, options.type)
       }
       else
       {

lib/sequelize.js

@@ -38,7 +38,9 @@ module.exports = (function() {
       logging: console.log,
       omitNull: false,
       queue: true,
-      native: false
+      native: false,
+      replication: false,
+      pool: {}
     }, options || {})
 
     if(this.options.logging === true) {
@@ -56,6 +58,7 @@ module.exports = (function() {
       protocol: this.options.protocol,
       queue   : this.options.queue,
       native  : this.options.native,
+      replication: this.options.replication,
       maxConcurrentQueries: this.options.maxConcurrentQueries
     }