From 32861b025a96c6acfe9714a1460aba5ad45a97b0 Mon Sep 17 00:00:00 2001
From: Rob <rob@codecombat.com>
Date: Tue, 17 Nov 2015 14:57:12 -0800
Subject: [PATCH] Support sending performance information to stats.

---
 package.json                  |  1 +
 server/commons/perfmon.coffee | 43 +++++++++++++++++++++++++++++++++++
 server_config.coffee          |  5 ++++
 server_setup.coffee           |  4 ++++
 4 files changed, 53 insertions(+)
 create mode 100644 server/commons/perfmon.coffee

diff --git a/package.json b/package.json
index 36a5dc034..0dfd4bc87 100644
--- a/package.json
+++ b/package.json
@@ -72,6 +72,7 @@
     "mongoose-cache": "~0.1.4",
     "node-force-domain": "~0.1.0",
     "node-gyp": "~0.13.0",
+    "node-statsd": "^0.1.1",
     "passport": "0.1.x",
     "passport-local": "0.1.x",
     "redis": "",
diff --git a/server/commons/perfmon.coffee b/server/commons/perfmon.coffee
new file mode 100644
index 000000000..e03b6145f
--- /dev/null
+++ b/server/commons/perfmon.coffee
@@ -0,0 +1,43 @@
+fs = require 'fs'
+path = require 'path'
+config = require '../../server_config'
+StatsD = require 'node-statsd'
+
+if config.statsd
+	realClient = new StatsD(config.statsd)
+else
+	mock = new StatsD(mock: true)
+
+exports.client = realClient or mock
+exports.middleware = (req, res, next) ->
+
+	req.statsd = exports.client
+	if realClient
+		time = process.hrtime();
+		cleanup = ->
+			res.removeListener 'finish', recordMetrics
+			res.removeListener 'error', cleanup
+			res.removeListener 'close', cleanup
+
+		recordMetrics = ->
+			diff = process.hrtime(time);
+			ms = (diff[0] * 1000 + diff[1] / 1e6);
+			path = req.route?.path or '/*'
+			stat = req.method + "." + path.replace /[^A-Za-z0-9]+/g, '_'
+			realClient.timing stat, ms
+			
+
+		res.once 'finish', recordMetrics
+		res.once 'error', cleanup
+		res.once 'close', cleanup
+	else
+		req.statsd = mock
+
+	next() unless not next
+
+exports.trace = (name, callback) ->
+	return callback unless realClient
+	time = process.hrtime()
+	(args...) ->
+		realClient.timing name, ms
+		return callback.apply(this, args)
\ No newline at end of file
diff --git a/server_config.coffee b/server_config.coffee
index 4507a8d7e..b8468f4c9 100644
--- a/server_config.coffee
+++ b/server_config.coffee
@@ -84,5 +84,10 @@ if not config.unittest and  not config.isProduction
   # change artificially slow down non-static requests for testing
   config.slow_down = false
 
+if process.env.COCO_STATSD_HOST
+  config.statsd =
+    host: process.env.COCO_STATSD_HOST
+    port: process.env.COCO_STATSD_PORT or 8125
+    prefix: process.env.COCO_STATSD_PREFIX or ''
 
 module.exports = config
diff --git a/server_setup.coffee b/server_setup.coffee
index ee327a830..230f7c56b 100644
--- a/server_setup.coffee
+++ b/server_setup.coffee
@@ -8,6 +8,7 @@ compressible = require 'compressible'
 geoip = require 'geoip-lite'
 
 database = require './server/commons/database'
+perfmon = require './server/commons/perfmon'
 baseRoute = require './server/routes/base'
 user = require './server/users/user_handler'
 logging = require './server/commons/logging'
@@ -127,8 +128,11 @@ setupRedirectMiddleware = (app) ->
     nameOrID = req.path.split('/')[3]
     res.redirect 301, "/user/#{nameOrID}/profile"
 
+setupPerfMonMiddleware = (app) ->
+  app.use perfmon.middleware
 
 exports.setupMiddleware = (app) ->
+  setupPerfMonMiddleware app
   setupCountryRedirectMiddleware app, "china", "CN", "zh", "tokyo"
   setupCountryRedirectMiddleware app, "brazil", "BR", "pt-BR", "saoPaulo"
   setupMiddlewareToSendOldBrowserWarningWhenPlayersViewLevelDirectly app