Simple Python Web App

Note

You can download the full source code for this tutorial

Project File

Create the project using:

mkdir -p ~/Projects/webapp
echo -e "com.nasos.webapp\n1.0\norg.debian.wheezy-lamp-1.2" | sudo rainbow --init ~/Projects/webapp/
sudo chown -R rainbow:rainbow ~/Projects/webapp

Edit ~/Projects/webapp/package.json so it contains:

{
    "type": "application", 
    "id": "com.nasos.webapp", 
    "version": "1.0", 
    "depends": [
        "org.debian.wheezy-lamp-1.2" 
    ], 
    "network_ports": {
        "WEB_UI": 8080 
    }
}

As can be seen, we will use the org.debian.wheezy-lamp-1.2, since we need Python, and we declare the port 8080 for our WEB_UI.

Startup Script

Create the source directory:

mkdir -p ~/Projects/webapp/source

And create the ~/Projects/webapp/source/rc.local file with the following content:

#!/bin/sh -e

PIDFILE=/var/run/webapp.pid
case $1 in
    start)
        start-stop-daemon --start \
                          --make-pidfile \
                          --pidfile $PIDFILE \
                          --background \
                          --startas /usr/bin/webapp.py 
        ;;
    stop)
        start-stop-daemon --stop --pidfile $PIDFILE
        rm -f $PIDFILE
        ;;
esac

exit 0

App Source Code

The app is composed of a single Python file. Create the ~/Projects/webapp/source/webapp.py file with the following content:

#!/usr/bin/python
import web
import os
urls = (
    os.environ['RAINBOW_WEB_PATH'], 'index',
    os.environ['RAINBOW_WEB_PATH'] + '/', 'index',
)

class index:
    def GET(self):
        return "Hello, world!"

class MyApplication(web.application):
    def run(self, port, *middleware):
        func = self.wsgifunc(*middleware)
        return web.httpserver.runsimple(func, ('0.0.0.0', port))

if __name__ == "__main__":
    web.config.debug = False
    app = MyApplication(urls, globals())
    app.run(port=int(os.environ['RAINBOW_PORT_WEB_UI']))

Build Script

Create the ~/Projects/webapp/build.sh file with the following content:

#!/bin/bash
install -m 755 /home/source/rc.local /etc
install -m 755 /home/source/webapp.py /usr/bin
pip install web.py
exit 0

This script:

Build the App

You can then build the app using:

sudo rainbow --build ~/Projects/webapp
sudo rainbow --pack ~/Projects/webapp

Then install it for testing:

sudo rainbow --install ~/Projects/webapp/build/x86_64/com.nasos.webapp-1.0-x86_64.rbw

And check its URL:

sudo rainbow --list com.nasos.webapp

Which should return something like:

-- com.nasos.webapp: Webapp
    version                         : 1.0
    architecture                    : x86_64
    install_path                    : /opt/rainbow/webapp-34da237
    state                           : running
    blocking_state                  : not_blocked
    startup_mode                    : auto
    install_id                      : webapp-34da237
    public_key_hash                 : None
    nasos_min_version               : None
    nasos_max_version               : None
    url                             : http://10.0.2.15/apps/webapp
    PIDS:
      \- 5306 : /usr/bin/python /usr/bin/webapp.py
    NETWORK PORTS:
      WEB_UI                        : 8080

Open the http://10.0.2.15/apps/webapp in the browser, you should get:

Testing the App