Socket Hang up problem - A sample to generate the problem.

test-simple-http-data.js

/*
 * This is a simple HTTP data generator for testing.
 *
 */

var http = require('http');

var counter = 0;
http.createServer(function (req, res) {
    var start = new Date();
    var myCounter = counter++;

    var timeout = 50;	// default timeout.  Mimic how much time it takes to run a process.
    
    // Controlled long response time causing timeout in client side. 
    if ( (myCounter % 20000) == 0) {
        console.log('-------- reach 20000 ------------');
        timeout = 600000;	// 10 minutes
    }

    // give it some timeout
    setTimeout(function() {
        var output = '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>\n';

                output += '<myData>ABCDE'+myCounter+'</myData>\n';
                
        console.log("output: " + myCounter);
        
        res.writeHead(200, {'Content-Type': 'application/xml'});
        res.write(output);
        res.end();
    }, timeout);


}).listen(3015);

console.log('Server running at port 3015');

test-simple-http-server.js

var http = require('http');

// option1 is the from Google.  GoogleAPI usually has less timeout and causing less issue. 

//https://ajax.googleapis.com/ajax/services/search/web?v=1.0&q=Paris%20Hilton&callback=foo&context=bar
var agent1 = http.getAgent('ajax.googleapis.com',80);
agent1.maxSockets = 2000;

var options1 = {
	agent:agent1,
    host: 'ajax.googleapis.com',
    port: 80,
    path: '/ajax/services/search/web?v=1.0&q=Paris%20Hilton&callback=foo&context=bar',
    method: 'GET',
    headers:{
		"Connection":"keep-alive"
	}
};

// option2 is your own server that feeds data.
var agent2 = http.getAgent('localhost', 80);
agent2.maxSockets = 2000;
var options2 = {
		agent:agent2,
		host:'localhost',
		port:80,
		path:'/',
		method:'GET',
		headers:{
				"Connection":"keep-alive"
			}
	};

// option3 is my AWS micro instance.   It has controlled timeout for ever 20000 request.
var agent3 = http.getAgent('50.19.237.122', 3015);
agent3.maxSockets = 2000;
var options3 = {
		agent:agent3,
		host:'50.19.237.122',
		port:3015,
		path:'/',
		method:'GET',
		headers:{
				"Connection":"keep-alive"
			}	
	};

// set which 
var workingOption = options3;

var counter = 0;

var server = http.createServer(function (req, res) {
	var myCounter = counter ++;
	console.log("Start: counter: " + myCounter);
	
    var start = new Date();	// just for timing.
    
    var clientRequest = http.request(workingOption, function(response) {
        
    	var result = '';
        response.setEncoding('utf8');
        res.writeHead(response.statusCode, {'Content-Type': 'application/xml'});
        response.on('data', function (chunk) {
        	result += chunk;
            if (!res.write(chunk)) { // if write failed, the stream is choking
                response.pause(); // tell the incoming stream to wait until output stream drained
            }
        }).on('end', function () {
            var end = new Date();
            console.log("End: counter: " + myCounter + ' Time: ' + (end-start) + " chunk: " + result.substring(0, 20));
            res.end();
        });
    });
    clientRequest.on('error', function(e) {
    	console.error("ERROR: " + JSON.stringify(e));
    	console.log("ERROR: " + JSON.stringify(e));
    });
    
    
    clientRequest.end();
});

server.listen(3204);

console.log('Server running at port 3204');