A PubSubHubBub Publisher implementation in Python
We wanted to use a defined spec with easy to use clients, and PubSubHubBub fit the bill nicely.
Why implement an external publisher?
The original impetus for this project is to adapt an existing piece of software to sending notifications without laying the job of managing those notifications on said implementation. Because PubSubHubBub requires an ATOM feed, we didn't want the original software from having to worry about completely unrelated functionality. Additionally, this route buys us a lot of flexibility.
- pubsubhubbub_publish (available under the publisher_clients folder after checking out the project from Google Code NOTE: the plan is to replace this dependency later with our implementation
- carrot (if using Rabbit)
Setting up the hub
Download the Google App Engine SDK for Linux and add it to your path
Then checkout the reference hub.
svn checkout http://pubsubhubbub.googlecode.com/svn/trunk/ pubsubhubbub-read-only
Install pubsubhubbub_publisher for python
cd pubsubhubbub-read-only/publisher_clients/python sudo python setup.py install
Start the hub
cd pubsubhubbub-read-only dev_appserver.py hub/ -p<port number specified in yagi.conf>
Setting up Yagi
After setting up the hub, above
cd yagi # edit yagi.conf, setting up as appropriate # Take care to update the feed_host variable in the event_feed # section as it will be the IP address presented in the feed. Otherwise # Yagi will attempt to infer it, and it doesn't seem to be all that # successful at it. sudo cp yagi.conf /etc sudo python setup.py install yagi-event yagi-feed
cd yagi # You'll want to run this in multiple screen windows or terminal sessions, as the callback process # won't daemonize python subscriber/callback.py <sub_port> python subscriber/sub.py <topic> <callback> <hub> # I usually load other/push_rabbit.py in an iPython session cd other ipython import push_rabbit # the cast below is assuming you setting up yagi to listen on a queue named 'notifications.warn' push_rabbit.cast(dict(a=3), 'instance', 'notifications', 'warn')
You should see XML content being pushed to your window running callback.py, above.