Story #4689
Updated by daviddavis about 4 years ago
## Motivation
Pulp as a multi-process system needs to make debugging easy. Currently it is hard to:
1. Identify which log statements are related to a specific API request
2. Filter out all of those that aren't
3. Do this across multiple processes
Additionally, there is a use case where an external system wants to provide the correlation id, e.g. Katello wants to submit the correlation ID as part of the request.
## Solution
Use [django-cid](https://django-correlation-id.readthedocs.io/en/latest/) by default, and document that it's available for users to use.
## Implementation
### Enabling in Pulp itself
1. Add django-cid as an installed app
2. Reconfigure the default Django logger config in [settings.py](https://github.com/pulp/pulpcore/blob/master/pulpcore/app/settings.py#L178-L190) to incorporate the CID
3. Add user documentation identifying the types of things they can additionally configure
4. Add a test to assert Pulp viewset logs contain an autogenerated CID
### Enabling in the App
1. Add a test to assert content app logs contain an autogenerated CID
### Enabling in Tasking System
1. **Create the field on task and set it**: Add a field to the Task model called `logging_cid`. Have the [`enqueue_with_reservation`](https://github.com/pulp/pulpcore/blob/b94abd64d76ea4554e6750ff38ce458eaa888cc8/pulpcore/tasking/tasks.py#L162) function set this field when it creates a Task object with the value of [`get_cid`](https://django-correlation-id.readthedocs.io/en/latest/api.html#cid.locals.get_cid).
2. **Have the CID log on the resource manager itself:** Have the [`_queue_reserved_task`](https://github.com/pulp/pulpcore/blob/b94abd64d76ea4554e6750ff38ce458eaa888cc8/pulpcore/tasking/tasks.py#L51) method call [`set_cid()`](https://django-correlation-id.readthedocs.io/en/latest/api.html#cid.locals.set_cid) with the value of the new `logging_cid` from the ``inner_task``. This will enable the correlation ID in the resource_manager logs for that task also.
3. **Have all tasks also use the CID:** Have the [`perform_job`](https://github.com/pulp/pulpcore/blob/e00d176a90783cc757de025cb5be4f5b810645bc/pulpcore/tasking/worker.py#L79) call [`set_cid()`](https://django-correlation-id.readthedocs.io/en/latest/api.html#cid.locals.set_cid) with the value of the `logging_cid` from the task. This will enable the correlation ID in all pulp task logs without them having to change their signatures.
4. Lastly, expose the `logging_cid` in the task API for users to see.
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