The Federated Message Bus, or Fedmsg, is used within the Fedora Infrastructure to easily connect services using ZeroMQ publishers and subscribers. This library is now deprecated in favour of Fedora Messaging.
Fedora Messaging provides a framework for declaring message schemas and a set of APIs to publish and consume messages to and from AMQP brokers.
In the project Fedora Happiness Packets, Fedmsg was set up to send messages to the Bus so that Fedora Badges could be awarded to the sender when they send a Happiness Packet, i.e an email worth of appreciation! My piece in this jigsaw was to migrate from Fedmsg to Fedora Messaging in this containerized project.