Fedora Infrastructure Message Bus

We want to hook all the services in Fedora Infrastructure up to send messages to one another over a message bus instead of communicating with each other in the heterogenous, “Rube-Goldberg” ways they do now.

fedmsg (Fedora-Messaging) is a python package and API used around Fedora Infrastructure to send and receive messages to and from applications. See Overview for a thorough introduction.

Click here to see a feed of the Fedora bus. There’s also a #fedora-fedmsg channel on the freenode network with a firehose bot echoing messages to channel to help give you a feel for what’s going on.

Receiving Messages with Python

import fedmsg

# Yield messages as they're available from a generator
for name, endpoint, topic, msg in fedmsg.tail_messages():
    print topic, msg

Receiving Messages from the Shell

$ fedmsg-tail --really-pretty

Publishing Messages with Python

See Development on setting up your environment and workflow.

import fedmsg
fedmsg.publish(topic='testing', modname='test', msg={
    'test': "Hello World",
})

Publishing Messages from the Shell

$ echo "Hello World." | fedmsg-logger --modname=git --topic=repo.update
$ echo '{"a": 1}' | fedmsg-logger --json-input
$ fedmsg-logger --message="This is a message."
$ fedmsg-logger --message='{"a": 1}' --json-input

Testimonials

  • Jordan Sissel – “Cool idea, gives new meaning to open infrastructure.”
  • David Gay – “It’s like I’m working with software made by people who thought about the future.”

Community

The source for this document can be found on github. The issue tracker can be found there, too.

Almost all discussion happens in #fedora-apps on the freenode network. There is also a mailing list.