Yesterday I spent some time to understand a problem with a Node Js application on Microsoft Azure. To be quick, my code was a simple web application built on top of Express and the code was something like this:
var express = require("express");
var app = express();
.... configure express
var port = Number(process.env.port || 5000);
app.listen(port, function() {
logger.info("Listening on " + port);
});
Running locally the code works very well both if you run it on your dev environment or a server. Unfortunately it doesn't work if you try to run it on Microsoft Azure Website. But Why?
Adding some log I identified the problem on the port environment, basically process.env.port returns a string instead of a number (to be precise it was \\.\pipe\e289ed7e-b57b-46bb-8bba-ad8cd1f1529c) f The solution is easy, do not try to convert it to a number but pass it as is to node:
var port = process.env.port || 5000;
app.listen(port, function() {
logger.info("Listening on " + port);
});
The reason is that Node is not running on its process like on local machine (node app.js to be clear), but it's mapped under IIS using IISNode with a wildcard on an HTTP Handler using named pipe
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<system.webServer>
<handlers>
<add name="iisnode" path="app.js" verb="*" modules="iisnode"/>
</handlers>
<rewrite>
<rules>
<rule name="StaticContent">
<action type="Rewrite" url="public{REQUEST_URI}"/>
</rule>
<rule name="DynamicContent">
<conditions>
<add input="{REQUEST_FILENAME}" matchType="IsFile" negate="True"/>
</conditions>
<action type="Rewrite" url="app.js"/>
</rule>
</rules>
</rewrite>
<iisnode
debuggingEnabled="false"
logDirectory="..\..\LogFiles\nodejs"
watchedFiles="*.js;iisnode.yml;node_modules\*;views\*.jade;views\*.ejb;routes\*.js;views\*.vash" />
</system.webServer>
</configuration>
For confirmation, I wrote to David Ebbo via twitter getting this answer:
Unfortunately (or not), right now there is no way to run Node outside of IIS on Azure Websites but maybe it's not a problem, it works 