python-openstackclient/doc/source/contributor/command-logs.rst

Command Logs

Logger usage in OpenStackClient is not exactly the same as those in other OpenStack projects. The following basic rules should be followed.

1. OpenStackClient uses python standard logging library instead of oslo.log so that it will depend on oslo as little as possible.
2. All logs except debug log need to be translated. The log message strings that need to be translated should follow the rule of i18n guidelines: https://docs.openstack.org/oslo.i18n/latest/user/guidelines.html
3. There are mainly two kinds of logs in OpenStackClient: command specific log and general log. Use different logger to record them. The examples below will show the detail.

Command specific log

Command specific logs are those messages that used to record info, warning and error generated from a specific command. OpenStackClient uses the logger of the module the command belongs to to record the command specific logs.

Example

This example shows how to log command specific logs in OpenStackClient.

import logging

from openstackclient.i18n import _


LOG = logging.getLogger(__name__)     # Get the logger of this module

## ...

    LOG.error(_("Error message"))
    LOG.warning(_("Warning message"))
    LOG.info(_("Info message"))
    LOG.debug("Debug message")        # Debug messages do not need to be translated

## ...

General log

General logs are those messages that not specific to any single command. Use the logger of openstackclient.shell to record them. In each command class, we can simply get this logger by self.app.log.

Example

This example shows how to log general logs in OpenStackClient.

from openstackclient.i18n import _


## ...

    self.app.log.error(_("Error message"))
    self.app.log.warning(_("Warning message"))
    self.app.log.info(_("Info message"))
    self.app.log.debug("Debug message")        # Debug messages do not need to be translated

## ...