add num files and socket monitoring

Author: anandkumarpatel

lib/express-app.js

@@ -16,6 +16,7 @@ app.use(require('connect-datadog')({
   'method':true,
   'tags': ['name:api', 'logType:express', 'env:'+process.env.NODE_ENV]
 }));
+app.use(dogstatsd.captureSocketCount);
 
 if (envIs('development', 'local', 'io')) {
   app.use(morganFreeman());

lib/models/datadog/index.js

@@ -3,7 +3,7 @@ var StatsD = require('node-dogstatsd').StatsD;
 var client = module.exports = new StatsD(
   process.env.DATADOG_HOST,
   process.env.DATADOG_PORT);
-
+var exec = require('child_process').exec;
 
 function captureSteamData (streamName, stream) {
   stream.on('data', function(){
@@ -21,5 +21,26 @@ function captureSteamData (streamName, stream) {
 }
 
 
+function captureSocketCount (req, res, next) {
+  var sockets = require('http').globalAgent.sockets;
+  var request = require('http').globalAgent.requests;
+  var key;
+
+  for (key in sockets) {
+    client.gauge('sockets_open', sockets[key].length, ['target:'+key]);
+  }
+
+  for (key in request) {
+    client.gauge('sockets_pending', request[key].length, ['target:'+key]);
+  }
+
+  exec('lsof -p ' + process.pid + ' | wc -l', function (err, stdout) {
+    if (err) { return; }
+    client.gauge('openFiles', parseInt(stdout), ['target:'+key]);
+  });
+
+  next();
+}
 
 module.exports.captureSteamData = captureSteamData;
+module.exports.captureSocketCount = captureSocketCount;