Middleware that makes a request GUID available from anywhere and injects it into your logs.


Keywords
django, logging, request, web, uuid, guid, correlation, correlation-id, django-correlation-id, django-guid, django-rest-framework
License
BSD-3-Clause
Install
pip install django-guid==1.1.1

Documentation

Django GUID

https://readthedocs.org/projects/django-guid/badge/?version=latest

Django GUID stores a GUID to an object, making it accessible by using the ID of the current thread. The GUID is accessible from anywhere within the application throughout a request, allowing us to inject it into the logs.

Example

Using demoproj as an example, all the log messages without django-guid would look like this:

INFO 2020-01-14 12:28:42,194 django_guid.middleware No Correlation-ID found in the header. Added Correlation-ID: 97c304252fd14b25b72d6aee31565843
INFO 2020-01-14 12:28:42,353 demoproj.views This is a DRF view log, and should have a GUID.
INFO 2020-01-14 12:28:42,354 demoproj.services.useless_file Some warning in a function

With django-guid every log message has a GUID attached to it(97c304252fd14b25b72d6aee31565843), through the entire stack:

INFO 2020-01-14 12:28:42,194 [None] django_guid.middleware No Correlation-ID found in the header. Added Correlation-ID: 97c304252fd14b25b72d6aee31565843
INFO 2020-01-14 12:28:42,353 [97c304252fd14b25b72d6aee31565843] demoproj.views This is a DRF view log, and should have a GUID.
INFO 2020-01-14 12:28:42,354 [97c304252fd14b25b72d6aee31565843] demoproj.services.useless_file Some warning in a function

For multiple requests at the same time over multiple threads, see the extended example docs.

Why

django-guid makes it extremely easy to track exactly what happened in any request. If you see an error in your log, you can use the attached GUID to search for any connected log message to that single request. The GUID can also be returned as a header and displayed to the end user of your application, allowing them to report an issue with a connected ID. django-guid makes troubleshooting easy.

Settings

  • SKIP_CLEANUP

    After the request is done, the GUID is deleted to avoid memory leaks. Memory leaks can happen in the case of many threads, or especially when using Gunicorn max_requests or similar settings, where the number of thread IDs can potentially scale for ever. Having clean up enabled ensures we can not have memory leaks, but comes at the cost that anything that happens after this middleware will not have the GUID attached, such as django.request or django.server logs. If you do not want clean up of GUIDs and know what you're doing, you can enable SKIP_CLEANUP.

    Default: False

  • GUID_HEADER_NAME

    The name of the GUID to look for in a header in an incoming request. Remember that it's case insensitive.

    Default: Correlation-ID

  • VALIDATE_GUID

    Whether the GUID_HEADER_NAME should be validated or not. If the GUID sent to through the header is not a valid GUID (uuid.uuid4).

    Default: True

  • RETURN_HEADER

    Whether to return the GUID (Correlation-ID) as a header in the response or not. It will have the same name as the GUID_HEADER_NAME setting.

    Default: True

  • EXPOSE_HEADER

    Whether to return Access-Control-Expose-Headers for the GUID header if RETURN_HEADER is True, has no effect if RETURN_HEADER is False. This is allows the JavaScript Fetch API to access the header when CORS is enabled.

    Default: True

Installation

Install using pip:

pip install django-guid

Then, in your project's settings.py add these settings:

Add the middleware to the MIDDLEWARE setting (if you want the correlation-ID to span your middleware-logs, put it on top):

MIDDLEWARE = [
    'django_guid.middleware.GuidMiddleware',
    ...
 ]

Add a filter to your LOGGING:

LOGGING = {
    ...
    'filters': {
        'correlation_id': {
            '()': 'django_guid.log_filters.CorrelationId'
        }
    }
}

Put that filter in your handler:

LOGGING = {
    ...
    'handlers': {
        'console': {
            'class': 'logging.StreamHandler',
            'formatter': 'medium',
            'filters': ['correlation_id'],
        }
    }
}

Lastly make sure we add the new correlation_id filter to the formatters:

LOGGING = {
    ...
    'formatters': {
        'medium': {
            'format': '%(levelname)s %(asctime)s [%(correlation_id)s] %(name)s %(message)s'
        }
    }
}

If these settings were confusing, please have a look in the demo project's settings.py file for a complete example.

If you wish to aggregate the django-guid logs to your console or other handlers, add django_guid to your loggers in the project. Example:

LOGGING = {
    ...
    'loggers': {
        'django_guid': {
            'handlers': ['console', 'logstash'],
            'level': 'WARNING',
            'propagate': False,
        }
    }
}

Inspired by django-log-request-id with a complete rewritten django-echelon approach.