Install Simple Node.js (Express) WebServer on bare AWS EC2 Linux AMI (201409, Fedora 19 "like")

install-simple-nodejs-webserver-on-ec2_aws_linux_ami_201409

#### Installs Nodejs and Express on a new AWS EC2 instance, running Linux AMI.
#    "Webserver" is about 10 lines of code in Express.js/Node
#    This works on RHEL systems (i.e. yum).
#    To install, do this on target machine (make sure to get the link from RAW gist):
#
#        $ sudo su -
#        $ curl https://gist...../raw/... | bash -s

#### Step 1:  Note OS
#    Installing Nodejs depends on which OS you're on.  Since I was on a AWS AMI
#    I needed to determine what Linux this was closest to, so I could determine
#    the simplest install instructions:

#### Step 2: Install nodejs and npm

yum -y update
yum -y --enablerepo=epel install nodejs npm
npm install npm -g
npm update -g

# Ignore bunch of dependency warnings...

#### Step 3: Create WebServer App and Install Express on Target Instance
#    We will now create a simple Nodejs app, the usual way, by creating an empty
#    directory, initializing a package.json, creating a .js program, and installing
#    the express dependencies.  The "web server" is about 10 lines of Javascript
#    code using Expressjs.

mkdir webserver
cd webserver
npm init
npm install express --save

# Create Javascript program "main.js" (copy and paste from below):
$ cat > main.js <<EOF
var express = require ('express');
var app = express ();

app.get ('/', function (req, res) {
    res.send ("Web server works!\n");
});

console.log ("Web server starting, attempting to listen on privileged port 80...");
app.listen (80);
console.log ("Listening on port 80");
EOF

#### Step 4: Start webserver and test
#    Since the webserver will be listening on port 80, which is privileged
#    we need to start with "sudo":
#
# To start:  $ sudo node main.js

#### Step 4:  Test locally
# We'll now make a curl request on the webserver
# In another shell window do:
# $ curl http://localhost/
# Web server works!

# You can test from another vm instance, providable the port and vm
# are reachable.