Limit length of log entries

[svenseeberg]

Short description

We sometimes have log entries with multiple megabytes of base64 encoded images. This breaks reading logs.

Proposed changes

Limit log messages to 4096 characters.

Side effects

• may cut messages.

Faithfulness to issue description and design

There are no intended deviations from the issue and design.

How to test

Resolved issues

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Pull Request Review Guidelines

[svenseeberg]

The failed test (generate unique slug) is unrelated to the PR.

[svenseeberg]

I already patched this onto the prod server to have a workaround for the long log messages.

[PeterNerlich]

I'm not sure how I feel about adding this blanket solution here. I opened up a PR on linkcheck instead, this targets specifically the problematic log message, and specifically data URLs: DjangoAdminHackers/django-linkcheck#219

I'm not sure what to expect regarding when it will be merged and land in a release however

[svenseeberg]

We can increase the length to 10k chars or whatever. But truncating too long log entries is something that many programs do to prevent problems.

[PeterNerlich]

Sounds good. I'm not sure about whether there is a better way than to just modify the RequestFormatter, but I have no good idea about how logging / django logging is supposed to work and at first glance it doesn't look like there is an easy way to chain formatters or something like that.

One note, if I remember correctly the 4096 will denote proper characters, not bytes, so the storage will still differ by line if some contain UTF characters. I don't think this is a problem though since our goal is to just keep the log file size from exploding