JSONRenderer and not serializable dict keys

[askurihin]

This code

import uuid
import structlog             

structlog.configure(processors=[structlog.processors.JSONRenderer()]) 
structlog.get_logger().info({uuid.uuid4(): 1})

fails with TypeError

TypeError: keys must be str, int, float, bool or None, not UUID

In my setup, I can fix this issue by using a custom json encoder, passed to json.dums using cls argument. What do you suggest, fix the issue in structlog code or mention this case in the docs?

[hynek]

This seems a very fringe use-case. Ultimately, if you want to pass non-standard datatypes into your log entries, you have to customize dumps anyway. If you want to have non-standard keys, that's even more true. I would recommend to do it via default argument if possible though.

[askurihin]

I didn't manage to make it work via default argument, as far as I understood, default is applied to values, not keys.

I think that is quite a fringe use-case, sure, but it can be useful for someony If it is mentioned in the docs. Will you accept a PR with such change?

[hynek]

Yes, because it’s rather unexpected that someone uses anything else than strings as keys. 😅

This use-case by itself is nothing I would want to add to the docs, since they are quite extensive already.

What I could imagine is an isolated chapter specifically on JSON logs that explains some beste practices and logging of custom types.