common_resources = ['products', 'availability', 'S3_feeds', 'S3_images']

#  sqs_handler.py

import boto.sqs
from boto.sqs.message import Message


class SqsHandler(object):

    service_name = None

    def __init__(
        self, aws_region, aws_access_key_id, aws_secret_access_key,
        aws_queue_name, logger, sleep_sec
    ):
        self.conn = boto.sqs.connect_to_region(
            aws_region,
            aws_access_key_id=aws_access_key_id,
            aws_secret_access_key=aws_secret_access_key
        )
        self.queue = self.conn.get_queue(aws_queue_name)
        self.logger = logger
        self.sleep_sec = sleep_sec

    # ...

    # ...

    def mq_loop(self):
        while True:
            try:
                message = self.queue.read()

                if message is not None:
                    body = message.get_body()
                    
                    if body["service"] == self.service_name: 
                        self.queue.delete_message(message)
                        self.process_message(body)

            except Exception:
                self.logger.error(traceback.format_exc())
            finally:
                time.sleep(self.sleep_sec)

    # ...

    # ...

    def process_message(self, body):
        raise NotImplementedError()

    def write_message(self, body):
        m = Message()
        m.set_body(body)
        self.queue.write(m)

# ...settings.base.py

# ...

GROUP_CONTROL_PANEL = 'control_panel'
GROUP_DASHBOARD = 'dashboard'
GROUP_SERVICES = 'services'
GROUP_AVAILABILITY = 'availability'
GROUP_AVAILABILITY_UPDATE = 'availability_update'
# ...

AWS_REGION = os.environ['AWS_REGION']
AWS_ACCESS_KEY_ID = os.environ['AWS_ACCESS_KEY_ID']
AWS_SECRET_ACCESS_KEY = os.environ['AWS_SECRET_ACCESS_KEY']

# ...

# ...settings.production.py

from .base import *


# ...

AWS_AVAILABILITY_QUEUE_NAME = 'availability'

# ...

# ...permissions.py


def group_check(user, groups):
    if not user.is_authenticated():
        return False

    if user.is_superuser:
        return True

    for group in groups:
        if not user.groups.filter(name=group).exists():
            raise PermissionDenied

    return True


def control_panel_group_check(user):
    groups = [settings.GROUP_CONTROL_PANEL]

    return group_check(user, groups)

# ...

# ...

def avl_update_group_check(user):
    groups = [
        settings.GROUP_CONTROL_PANEL,
        settings.GROUP_DASHBOARD,
        settings.GROUP_SERVICES,
        settings.GROUP_AVAILABILITY,
        settings.GROUP_AVAILABILITY_UPDATE,
    ]

    return group_check(user, groups)

# ...

# ...views.availability.py

@require_POST
@login_required
@user_passes_test(avl_update_group_check)
def avl_update(request):

    # ....

    test_only = request.POST.get('test_only', False)
    send_email = request.POST.get('send_email', False)
    queue_name = settings.AWS_AVAILABILITY_QUEUE_NAME

    body = {
        "service": "availability",
        "parameters": {
            "test_only": test_only,
            "send_email": send_email,
        }
    }

    mq = SqsHandler(
        settings.AWS_REGION,
        settings.AWS_ACCESS_KEY_ID,
        settings.AWS_SECRET_ACCESS_KEY,
        queue_name,
        logger,
        settings.MQ_LOOP_SLEEP_SEC
    )

    mq.write_message(json.dumps(body))

    # ....

#  mq_loop.py

# ...

class SqsAvlHandler(SqsHandler):

    service_name = "availability"

    def process_message(self, body):
        message = json.loads(body)

        service = message["service"]

        if service == service_name:
            test_only = message["parameters"]["test_only"]
            send_email = message["parameters"]["send_email"]

            avl(test_only, send_email)
        else:
            raise Exception(
                "Service {0} not supported.".format(service))

    # ...

# mq_loop.py

# ...

if __name__ == "__main__":

    # ...

    mq = SqsAvlHandler(
        settings.AWS_REGION,
        settings.AWS_ACCESS_KEY_ID,
        settings.AWS_SECRET_ACCESS_KEY,
        settings.AWS_AVAILABILITY_QUEUE_NAME,
        logger,
        settings.AVAILABILITY_LOOP_SLEEP_SEC
    )

    mq.mq_loop()

# mq_loop.sh

#!/bin/bash

source /var/.virtualenvs/avl/bin/activate
cd /var/avl
python mq_loop.py

# /etc/init/avl.conf

description "Availability update"

# Start up when the system hits any normal runlevel, and
# shuts down when the system goes to shutdown or reboot.
# 
# 0 : System halt.
# 1 : Single-User mode.
# 2 : Graphical multi-user plus networking (DEFAULT)
# 3 : Same as "2", but not used.
# 4 : Same as "2", but not used.
# 5 : Same as "2", but not used.
# 6 : System reboot.
start on runlevel [2345]
stop on runlevel [06]

# respawn the job up to 10 times within a 5 second period.
# If the job exceeds these values, it will be stopped and
# marked as failed.
respawn
respawn limit 10 5

setuid avl
setgid avl

exec /var/avl/mq_loop.sh

/etc/init/avl.conf

/etc/init.d/avl > /lib/init/upstart-job

# helloworld.py

from nameko.rpc import rpc


class GreetingService(object):

    name = "greeting_service"

    @rpc
    def hello(self, name):
        return "Hello, {}!".format(name)

# http.py

import json
from nameko.web.handlers import http


class HttpService(object):

    name = "http_service"

    @http('GET', '/get/<int:value>')
    def get_method(self, request, value):
        return json.dumps({'value': value})

    @http('POST', '/post')
    def do_post(self, request):
        return "received: {}".format(request.get_data(as_text=True))

$ curl -i localhost:8000/get/42
HTTP/1.1 200 OK
Content-Type: text/plain; charset=utf-8
Content-Length: 13
Date: Fri, 13 Feb 2015 14:51:18 GMT

{'value': 42}