The module castellan.common.config will attempt to set some logging defaults and then register the configuration options. This causes an error for castellan consumers that have already registered and processed their configuration options. Additionally, the behavior in this module could overwrite the existing default logging message template, and might affect log levels in general.
Steps to reproduce:
1. create a simple application to demonstrate the error, this application follows a design pattern that is used for many OpenStack applications:
from oslo_config import cfg
from oslo_log import log
from castellan import key_manager
log.register_options(cfg.CONF)
cfg.CONF()
castellan_api = key_manager.API()
2. run the application
$ python log_error_test.py
Traceback (most recent call last):
File "log_error_test.py", line 10, in <module>
castellan_api = key_manager.API()
File "/home/mike/.venvs/sahara/lib/python2.7/site-packages/castellan/key_manager/__init__.py", line 34, in API
config.configure_logging()
File "/home/mike/.venvs/sahara/lib/python2.7/site-packages/castellan/common/config.py", line 31, in configure_logging
log.register_options(CONF)
File "/home/mike/.venvs/sahara/lib/python2.7/site-packages/oslo_log/log.py", line 242, in register_options
conf.register_cli_opts(_options.common_cli_opts)
File "/home/mike/.venvs/sahara/lib/python2.7/site-packages/oslo_config/cfg.py", line 1902, in __inner
result = f(self, *args, **kwargs)
File "/home/mike/.venvs/sahara/lib/python2.7/site-packages/oslo_config/cfg.py", line 2084, in register_cli_opts
self.register_cli_opt(opt, group, clear_cache=False)
File "/home/mike/.venvs/sahara/lib/python2.7/site-packages/oslo_config/cfg.py", line 1906, in __inner
return f(self, *args, **kwargs)
File "/home/mike/.venvs/sahara/lib/python2.7/site-packages/oslo_config/cfg.py", line 2076, in register_cli_opt
raise ArgsAlreadyParsedError("cannot register CLI option")
oslo_config.cfg.ArgsAlreadyParsedError: arguments already parsed: cannot register CLI option
Recommended action.
This logging configuration should be re-assessed as it is being called everytime a user might acquire the API object for castellan. I don't think the library should be performing the action of configuring the log style or levels, these decisions should be left up to the application that consumes castellan.
I think the best possible option would be to provide this functionality as a configuration call that the user could make at an appropriate time in their application. There should also be documentation about how to increase the logging level for castellan.
Fernando, another issue with the configure_logging function is that it should accept a ConfigOpt object instead of using the global oslo_config CONF object. The other configuration options have all been set to accept a user defined ConfigOpt and only use the global CONF is nothing is provided. This allows the consumer of castellan to be in full control of the configuration object that is used by their application.