Python script to watch a Docker Cloud service for redeployment

main.py

#!/usr/bin/python

import dockercloud
import logging
import json
import signal
import sys
import os

# To use this script you'll need to set the following environment variables
#
# DOCKERCLOUD_USER      - docker cloud user
# DOCKERCLOUD_APIKEY    - docker cloud api key
# DOCKERCLOUD_WATCH_SVC - the docker cloud UUID of the service you want to watch


logger = logging.getLogger("docker-cloud-watcher")


def get_uuid_from_resource_uri(uri):
    terms = uri.strip("/").split("/")
    if len(terms) < 2:
        return ""
    return terms[-1]


def on_websocket_open():
    logger.info("websocket opened")


def on_websocket_close():
    logger.info("websocket closed")


def on_cloud_event(message):

    try:
        event = json.loads(message)
    except ValueError:
        logger.info("event is not a valid json message")
        return

    uuid = get_uuid_from_resource_uri(event.get("resource_uri", ""))

    if event.get("state", "") not in ["In progress", "Pending", "Terminating", "Starting", "Scaling", "Stopping", "Running"] and \
        event.get("type", "").lower() in ["service"] and \
        uuid == os.getenv("DOCKERCLOUD_WATCH_SVC"):

        msg = "\n\nDocker Cloud Event: %s %s is %s\n" % (event["type"], uuid, event["state"].lower())
        logger.info(msg)


def listen_dockercloud_events():
    events = dockercloud.Events()
    events.on_open(on_websocket_open)
    events.on_close(on_websocket_close)
    events.on_message(on_cloud_event)
    events.run_forever()



def main():
    logging.basicConfig(stream=sys.stdout)
    logging.getLogger("docker-cloud-watcher").setLevel(logging.DEBUG)

    signal.signal(signal.SIGTERM, sys.exit)

    if os.environ.has_key("DOCKERCLOUD_USER") == False or os.environ.has_key("DOCKERCLOUD_APIKEY") == False:
        print "Docker cloud environment variables (DOCKERCLOUD_USER, DOCKERCLOUD_APIKEY, DOCKERCLOUD_WATCH_SVC) are not set!!!"
        exit()

    listen_dockercloud_events()


if __name__ == "__main__":
    main()