Typo in section header in config silently disables all config parsing

[George Shuklin]

I know it sounds silly, but I just spend five hours trying to find why glance is not working with swift and printing random erros. At the end I had found it had ignored all debug/log settings, and later I had found the source of the problem - small typo in my config.

If config contains '[[DEFAULT]' instead of '[DEFAULT]' glance ignores all setting in section (i think it is not only for 'default', but 'default' is the most devastating, because it disables logging and logging locations).

Proposed solution: write down a warning to stdout if configuration file contains no '[DEFAULT]' section.

[Louis Taylor (kragniz)]

This doesn't actually work for me on master. On a plain devstack installation, replacing [DEFAULT] with [[DEFAULT] or [xDEFAULT] in /etc/glance/glance-api.conf causes the service to fail to start. It complains it can't read a certain option from the config file:

    2015-01-20 15:28:29.916 5741 TRACE glance BadDriverConfiguration: Driver glance.image_cache.drivers.sqlite could not be configured correctly. Reason: Failed to read image_cache_dir from config

Do you have some steps to reproduce?

[George Shuklin (george-shuklin)]

Hello. I check it on juno (sorry, got no devstack nearby).

Conditions:

1. Install any favorite distibution (I check it on ubuntu, but others should behave same way)
2. Stop system-wide glance (service glance-api stop)
3. Keep all other configuration files as is (paste.ini, etc).
3. In glance-api.conf replace [default] with [[default]
4. run glance-api from command line.

It will run without any complains to stdout and will ignore all settings in [[default] section.

Minimal 'bad' config it can use without complains looks like this:

[[DEFAULT]
image_cache_dir = /var/lib/glance/image-cache/
[glance_store]
filesystem_store_datadir = /var/lib/glance/images/

[Inessa Vasilevskaya (ivasilevskaya)]

I checked it on kilo -> server fails to start with the same trace as Louis mentioned:
2015-02-26 19:38:23.519 10003 TRACE glance BadDriverConfiguration: Driver glance.image_cache.drivers.sqlite could not be configured correctly. Reason: Failed to read image_cache_dir from config

[Kamil Rykowski (kamil-rykowski)]

Right, checked it on the latest master branch and the same behaviour occurs (BadDriverConfiguration).

[Hassaan Pasha (hassaanp)]

I reconfirmed on Juno.

The error message is handled by the following excerpt:

if self.base_dir is None:
            msg = _('Failed to read %s from config') % 'image_cache_dir'

Changing tags other than [Default] doesn't cause any trouble.
So should we simply change the error message to a more revealing one?