django-cid 2.1

Correlation IDs in Django for debugging requests

Logging is important. Anyone who has had a call at 3am to say the site is down knows this. Without quality logging it is almost impossible to work out what on earth is happening.

The more you log, the harder it is to track down exactly what the effects of a particular request are. Enter Django Correlation ID. Incoming requests are assigned a unique identifier. This can either happen in your public facing web server (e.g. nginx) or be applied by Django itself.

This correlation id (also known as request id) is then available through the Django request/response cycle and may be automatically included in all log messages. That way, you can easily link all log messages that relate to the same request:

2018-10-01T08:18:39.86+00:00 correlation_id=2433d5d4-27a3-4889-b14b-107a131368a3 Call to plug from cpoint=1
2018-10-01T08:18:39.90+00:00 correlation_id=72fbd7dd-a0ba-4f92-9ed0-0db358338e86 Call to state by cpoint=2 with {'state': {'B': 'idle', 'A': 'on_charge'}}
2018-10-01T08:18:39.92+00:00 correlation_id=2433d5d4-27a3-4889-b14b-107a131368a3 Ended rental=7 customer="John Smith" on plug

In this example, we can see that the first and the third log messages are tied to the same request, while the second message relates to a distinct request.

In addition to these logs, django-cid can include the correlation id:

• in all SQL queries (as a comment);

• in rendered templates;

• as a header in the HTTP response generated by Django;

• and possibly anywhere by using the API of django-cid, for example as an HTTP header on a request to another internal system of yours, which is especially useful in service-oriented architecture.

Documentation can be found at: https://django-correlation-id.readthedocs.org/

Sources are on GitHub: https://github.com/Polyconseil/django-cid

Supported versions

We currently support the following versions:

• Django 2.2 with Python >= 3.5.

• Django 3.0 with Python >= 3.6.

Other versions may work but are not supported.

History

2.1 (2020-06-22)

• Add support of Django 3.0

• backward incompatible: Drop support of Django 2.1.

2.0 (2019-09-27)

• backward incompatible: Drop support of Python 3.4.

• backward incompatible: Drop support of Django 1.11 and Django 2.0.

• Add CID_GENERATOR setting to allow the customization of the correlation id.

1.3 (2018-10-09)

• bugfix: Fix packaging bug (introduced in version 1.2) that caused two extra packages tests and sandbox to be installed.

1.2 (2018-10-08)

• bugfix: Fix bug (introduced in version 1.0) that caused the correlation id to be reused across all requests that were processed by the same thread.

1.1 (2018-10-01)

• Allow to concatenate an upstream correlation id with a locally-generated one, with a new CID_CONCATENATE_IDS setting.

1.0 (2018-10-01)

Warning: this release includes changes that are not backward compatible. Be sure to read the details below to know if and how you can migrate.

• backward incompatible: Drop support of Django 1.10 and earlier.

• backward incompatible: Drop support of Python 2.

• Add support of Django 2. Version 0.x could already be used with Django 2 but tests were not run against it. They now are.

• Generate cid outside of the middleware when GENERATE_CID is enabled, so that it’s available even if the middleware is not used.

• Fix support of Django 1.11 in database backends.

• Add PostGIS database backend.

• Add CID_SQL_COMMENT_TEMPLATE to customize how the cid is included as comments in SQL queries.

• backward incompatible: Change the app name to be used in INSTALLED_APPS.

  Migration from version 0.x: if you had cid in INSTALLED_APPS, replace it by cid.apps.CidAppConfig. If you did not, add the latter.

• backward incompatible: Drop compatibility with MIDDLEWARE_CLASSES. You should use the MIDDLEWARE setting. If you already did, no change is necessary.

  If you really must use the old MIDDLEWARE_CLASSES setting, include CidOldStyleMiddleware instead of CidMiddleware.

0.2.0 (2016-12-06)

• Added support for Django 1.10 middleware (thanks @qbey)

0.1.2 (2016-12-01)

• Made CID repsonse header configurable, and optional (thanks @dbaty)

0.1.0 (2014-08-05)

• First release on PyPI.