common.utils.readconf SystemExit is noisy

[clayg]

Anytime you want to use swift.common.utils.readconf if you don't want your program to exit when the config doesn't have the section you're looking for - you have to "handle" a SystemExit.

There's a couple of places in tree that do this, e.g.

https://github.com/openstack/swift/blob/2bf5eb775fe3ad6d3a2afddfc7572318e85d10be/swift/obj/auditor.py#L54

That's.... fine.... i guess - but the real problem is the message that gets spewed to STDOUT:

May 4 17:11:17 precisenode0 object-auditor: STDOUT: Unable to find object-replicator config section in /etc/swift/object-server/1.conf

^ happens every pass when a new AuditorWorker is created/forked.

1) refactor readconf to raise a different error if the section isn't defined (probably ValueError?) - include the helpful text *in* the Exception
2) find all the call-sites of readconf that want to exit - and catch the ValueError and translate the message to SystemExit
3) find all the call-sites of readconf that *don't* want to exit - and catch the ValueError and observe no messages are sent to stdout/logged

optional step 4 is to worry about all there that was handling readconf's SystemExit that will have to be updated to handle ValueError...

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/393388

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/393388
Committed: https://git.openstack.org/cgit/openstack/swift/commit/?id=ffd5194a3be8cd5fced038cc25ea1d8f78be1ea9
Submitter: Jenkins
Branch: master

commit ffd5194a3be8cd5fced038cc25ea1d8f78be1ea9
Author: Christian Hugo <email address hidden>
Date: Thu Nov 3 17:01:35 2016 +0100

    Raise ValueError if a config section does not exist

    Instead of printing the error message and
    calling sys.exit() when a section not exists
    or reading the file failed rais an Exception
    from readconfig. Depending on the Value or IO-Error,
    the caller can decide if he wants to exit or continue.
    If an Exception reaches the wsgi utilities
    it bubbles all the way up.

    Change-Id: Ieb444f8c34e37f49bea21c3caf1c6c2d7bee5fb4
    Closes-Bug: 1578321

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/swift 2.13.0 release.