oslo.log – user_identity format flexibility


The goal of this blueprint is to make it easier to adjust the format of the user_identity field in the log line without having to specify the full log format string.

Problem description

  • We want devstack to log identity using names, but by default we want identity to use UUID values because they are guaranteed to be unique.

  • We don’t want devstack to override the format string for projects individually.

  • We do want devstack to be able to change the default format without having to specify the whole string, for this leaves devstack with no info on anything added into the default formatting string.

Proposed change

Since oslo.context is not using oslo.config, and is incorrectly enforcing formatting, we want to make this change to oslo.log.

Let oslo.log control the formatting for the user_identity value in the log output. We have to leave the value in place in oslo.context, but we don’t have to use it any more.

Add a new configuration option to specify how to format the user_identity field. (We might find it useful to do this for other fields in the future, too, but let’s focus on one for now.)

Update oslo.log so it asks oslo.context for the values, and then replaces the user_identity with a string it builds itself using values it gets from oslo.context and the format string it gets from its configuration option.


We could require anyone wanting to customize the log format to replace the entire format string, but that makes it a little harder to adjust just part of it as we standardize the overall structure of the log messages.

We could place the configuration option in oslo.context, but that library is not using oslo.config yet and it should not have log formatting logic embedded in it.

Impact on Existing APIs

None. The RequestContext from oslo.context will still need to provide user_identity for backwards compatibility.

Security impact

The result will be no more or less secure than before.

Performance Impact

One extra format call should not have a big performance impact.

Configuration Impact

One new configuration option, with the default set up to result in the same format we have now.

Developer Impact

Users of devstack will eventually be able to see user identity in a nicer format.

Testing Impact

No significant change.



Primary assignee: doug-hellmann

Other contributors: ihrachyshka


Target Milestone for completion: liberty-3

Work Items

  1. add a new config option to oslo.log to control how the user_identity values are formatted; default it to what oslo.context does now

  2. add a new method to oslo.context to provide identity values to go into that format string (or just use the whole context dict?) Dict is fine.

  3. update oslo.log to build a new string and update the dictionary given to it from to_dict() always

  4. update devstack to set the new configuration option in a way that uses names instead of, or in addition to, uuids



Documentation Impact

The new configuration option needs to be documented.




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