One-file Pyramid app

gistfile1.py

# we'll use gevent to run the webserver, so one-thread, evented IO
import gevent.monkey
gevent.monkey.patch_all()
import gevent.pywsgi

from pyramid.config import Configurator
from pyramid.response import Response

from boto.ec2.connection import EC2Connection

# conf vars
USER_DATA = """#!/bin/bash
set -x -e
apt-get update
aptitude -y install less screen php5-cli php5-mysql php5-curl
"""
AWS_ID = 'id'
AWS_SECRET = 'secret'
AMI = 'ami'
INSTANCE_TYPE = 'm1.small'
SECURITY_GROUP = 'ssh'
KEYPAIR = 'secret'
AUTH_PASS = 'another secret'


def start_instance(conn, user_data):
    """Wrap starting a spot request."""
    return conn.request_spot_instances('0.50', AMI, count=1, key_name=KEYPAIR, security_groups=[SECURITY_GROUP], user_data=user_data, instance_type=INSTANCE_TYPE)


def shutdown_and_start(request):
    inst_id = int(request.matchdict['id'])
    if 'password' in request.params:
        if request.params['password'] == AUTH_PASS:
            if inst_id in request.registry.settings['instances']:
                inst = request.registry.settings['instances'][inst_id]
                conn = EC2Connection(AWS_ID, AWS_SECRET)
                match = conn.get_all_spot_instance_requests([inst['spot_id']])
                if match:
                    # kill old
                    # since we're using spot instances, have to dig around a bit to get
                    # the instance itself
                    match = conn.get_all_instances([match[0].instance_id])
                    if match:
                        match[0].instances[0].terminate()
                # start new
                request.registry.settings['i_counter'] += 1
                inst_id = request.registry.settings['i_counter']
                r = start_instance(conn, USER_DATA)
                request.registry.settings['instances'][inst_id] = {'spot_id': r[0].id}
                return {'success': True}
            else:
                return {'success': False, 'reason': 'Unknown ID'}
        else:
            return {'success': False, 'reason': 'Bad Password'}
    else:
        return {'success': False, 'reason': 'No Password Specified'}


def new_server(request):
    if 'password' in request.params:
        if request.params['password'] == AUTH_PASS:
            conn = EC2Connection(AWS_ID, AWS_SECRET)
            request.registry.settings['i_counter'] += 1
            inst_id = request.registry.settings['i_counter']
            r = start_instance(conn, USER_DATA)
            request.registry.settings['instances'][inst_id] = {'spot_id': r[0].id}
            return {'success': True}
        else:
            return {'success': False, 'reason': 'Bad Password'}
    else:
        return {'success': False, 'reason': 'No Password Given'}


if __name__ == '__main__':
    config = Configurator()
    # url dispatch, just render results as JSON, really simple REST interface
    config.add_route('main', '/cycle/{id}', shutdown_and_start, view_renderer='json')
    config.add_route('new', '/new', new_server, view_renderer='json')

    # these are available to every request and are essentially global (but note they are specific to a thread)
    config.registry.settings['i_counter'] = 0
    config.registry.settings['instances'] = {}
    
    app = config.make_wsgi_app()
    gevent.pywsgi.WSGIServer(('0.0.0.0', 8080), app).serve_forever()