Config file generator cannot discover oslo.messaging config options

[Mark McLoughlin]

See e.g. https://review.openstack.org/39929

Porting Nova to oslo.messaging meant that all the messaging related config options disappeared from the sample config file

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/59989

[Mark McLoughlin (markmc)]

See also https://etherpad.openstack.org/p/icehouse-oslo-config-import-side-effects

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/66029

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/66955
Committed: https://git.openstack.org/cgit/openstack/oslo-incubator/commit/?id=5dce17bcee873d931df2467d437e04c8d93fefb2
Submitter: Jenkins
Branch: master

commit 5dce17bcee873d931df2467d437e04c8d93fefb2
Author: Doug Hellmann <email address hidden>
Date: Wed Jan 15 21:51:59 2014 +0000

    Use entry points to discover options in libraries

    When generating the sample configuration file, we want to include
    options defined in libraries used by the application (especially
    oslo libraries). Add a section to the sample generator to look
    at entry points in the 'oslo.config.opts' namespace and include
    their return values in the output.

    Implements: blueprint improve-config-discovery-for-docs
    Related-Bug: #1241566

    Change-Id: I635cd8e60ca687851c9dd891667ecc2ca3e8720c

[Mark McLoughlin (markmc)]

changes to make this happen in Nova:

  oslo.messaging - https://review.openstack.org/66029
  oslo-incubator - https://review.openstack.org/69355
  nova - https://review.openstack.org/69357

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/66029
Committed: https://git.openstack.org/cgit/openstack/oslo.messaging/commit/?id=0eb5a6f6c73b1300021dd8afef69459fa5b0f6cb
Submitter: Jenkins
Branch: master

commit 0eb5a6f6c73b1300021dd8afef69459fa5b0f6cb
Author: Mark McLoughlin <email address hidden>
Date: Fri Jan 10 17:43:02 2014 +0000

    Expose an entry point to list all config options

    Register a oslo.messaging entry point in the oslo.config.opts namespace
    which, when called, returns a list of the configuration options which
    may be registered by the library at runtime.

    The idea here is that the sample config file generator can query this
    and include the returned options in the sample config file of any
    applications which use the library.

    Some sample code for fetching available options:

      import pkg_resources

      for ep in pkg_resources.iter_entry_points('oslo.config.opts'):
          if ep.name == "oslo.messaging":
              list_opts = ep.load()
              for g, opts in list_opts():
                  opts.sort(key=lambda x: x.name)
                  print "[%s]" % g
                  for o in opts:
                      print "%s = %s" % (o.name, o.default)
                  print

    Related-Bug: #1241566
    Change-Id: Ic28351258652d2ea38974e2f4d1aa6b1d3dd7192