infra-docs-fpo/modules/sysadmin_guide/pages/fedmsg-introduction.adoc

= fedmsg introduction and basics, SOP

General information about fedmsg

== Contact Information

Owner::
  Messaging SIG, Fedora Infrastructure Team
Contact::
  #fedora-apps, #fedora-admin, #fedora-noc
Servers::
  Almost all of them.
Purpose::
  Introduce sysadmins to fedmsg tools and config

== Description

_fedmsg_ is a system that links together most of our webapps and services
into a message mesh or net (often called a "bus"). It is built on top of
the zeromq messaging library.

_fedmsg_ has its own developer documentation that is a good place to check
if this or other SOPs don't provide enough information -
http://fedmsg.rtfd.org

== Tools

Generally, _fedmsg-tail_ and _fedmsg-logger_ are the two most commonly used
tools for debugging and testing. To see if bus-connectivity exists
between two machines, log onto each of them and run the following on the
first:

....
$ echo testing from $(hostname) | fedmsg-logger
....

And run the following on the second:

....
$ fedmsg-tail --really-pretty
....

== Configuration

_fedmsg_ configuration lives in `/etc/fedmsg.d/`

`/etc/fedmsg.d/endpoints.py` keeps the list of every possible fedmsg
endpoint. It acts as a global index that defines the bus.

See https://fedmsg.readthedocs.org/en/stable/configuration/ for a full glossary of
configuration values.

== Logs

_fedmsg_ daemons keep their logs in `/var/log/fedmsg`. _fedmsg_ message hooks
in existing apps (like bodhi) will log any errors to the logs of the app
they've been added to (like `/var/log/httpd/error_log`).