From 5b8c9a9d4caaca36c6d79f2754fd3be254b2803d Mon Sep 17 00:00:00 2001
From: henrique <henrique@ub32.(none)>
Date: Tue, 27 Aug 2013 15:06:42 +0200
Subject: [PATCH] THRIFT-2058:Add reconnect support to node.js library Client:
 nodejs Patch: Hamed Madani

---
 lib/nodejs/lib/thrift/connection.js | 82 ++++++++++++++++++++++++++++-
 1 file changed, 81 insertions(+), 1 deletion(-)

diff --git a/lib/nodejs/lib/thrift/connection.js b/lib/nodejs/lib/thrift/connection.js
index a49d427d..904d7bd8 100644
--- a/lib/nodejs/lib/thrift/connection.js
+++ b/lib/nodejs/lib/thrift/connection.js
@@ -35,6 +35,21 @@ var Connection = exports.Connection = function(stream, options) {
   this.offline_queue = [];
   this.connected = false;
 
+  this._debug = options.debug || false;
+  if (options.max_attempts
+     && !isNaN(options.max_attempts) && options.max_attempts > 0) {
+     this.max_attempts = +options.max_attempts;
+  }
+  this.retry_max_delay = null;
+  if (options.retry_max_delay !== undefined
+     && !isNaN(options.retry_max_delay) && options.retry_max_delay > 0) {
+     this.retry_max_delay = options.retry_max_delay;
+  }
+  this.connect_timeout = false;
+  if (options.connect_timeout
+     && !isNaN(options.connect_timeout) && options.connect_timeout > 0) {
+     this.connect_timeout = +options.connect_timeout;
+  }
   this.connection.addListener("connect", function() {
     self.connected = true;
 
@@ -43,6 +58,7 @@ var Connection = exports.Connection = function(stream, options) {
     this.frameLeft = 0;
     this.framePos = 0;
     this.frame = null;
+    self.initialize_retry_vars();
 
     self.offline_queue.forEach(function(data) {
       self.connection.write(data);
@@ -58,11 +74,14 @@ var Connection = exports.Connection = function(stream, options) {
         || self.listeners('error').length > 0) {
       self.emit("error", err)
     }
+    // "error" events get turned into exceptions if they aren't listened for.  If the user handled this error
+    // then we should try to reconnect.
+    self.connection_gone();
   });
 
   // Add a close listener
   this.connection.addListener("close", function() {
-    self.emit("close");
+    self.connection_gone(); // handle close event. try to reconnect
   });
 
   this.connection.addListener("timeout", function() {
@@ -102,6 +121,14 @@ Connection.prototype.end = function() {
   this.connection.end();
 }
 
+Connection.prototype.initialize_retry_vars = function () {
+  this.retry_timer = null;
+  this.retry_totaltime = 0;
+  this.retry_delay = 150;
+  this.retry_backoff = 1.7;
+  this.attempts = 0;
+};
+
 Connection.prototype.write = function(data) {
   if (!this.connected) {
     this.offline_queue.push(data);
@@ -110,6 +137,59 @@ Connection.prototype.write = function(data) {
   this.connection.write(data);
 }
 
+Connection.prototype.connection_gone = function () {
+  var self = this;
+
+  // If a retry is already in progress, just let that happen
+  if (this.retry_timer || !this.max_attempts) {
+	 return;
+  }
+
+  this.connected = false;
+  this.ready = false;
+
+  if (this.retry_max_delay !== null && this.retry_delay > this.retry_max_delay) {
+    this.retry_delay = this.retry_max_delay;
+  } else {
+    this.retry_delay = Math.floor(this.retry_delay * this.retry_backoff);
+  }
+
+  if (self._debug) {
+    console.log("Retry connection in " + this.retry_delay + " ms");
+  }
+
+  if (this.max_attempts && this.attempts >= this.max_attempts) {
+    this.retry_timer = null;
+    console.error("thrift: Couldn't get thrift connection after " + this.max_attempts + " attempts.");
+    self.emit("close");
+    return;
+  }
+
+  this.attempts += 1;
+  this.emit("reconnecting", {
+    delay: self.retry_delay,
+    attempt: self.attempts
+  });
+
+  this.retry_timer = setTimeout(function () {
+    if (self._debug) {
+       console.log("Retrying connection...");
+	}
+
+    self.retry_totaltime += self.retry_delay;
+
+    if (self.connect_timeout && self.retry_totaltime >= self.connect_timeout) {
+       self.retry_timer = null;
+       console.error("thrift: Couldn't get thrift connection after " + self.retry_totaltime + "ms.");
+       self.emit("close");
+       return;
+    }
+
+    self.connection.connect(self.port, self.host);
+    self.retry_timer = null;
+  }, this.retry_delay);
+};
+
 exports.createConnection = function(host, port, options) {
   var stream = net.createConnection(port, host);
   var connection = new Connection(stream, options);
-- 
2.17.1