extended json serialization

[antonkulaga]

I added more types for json serialization and tests for them. The tests run only if the libraries are installed.

[itamarst]

Thank you!

I like the functionality. I'm a little worried this will make logging slower, but I guess you only hit the path if it's not one of the types orjson already supports, so that's a start.

Making things faster:

• orjson already does some of these types (https://github.com/ijl/orjson?tab=readme-ov-file#serialize), so writing serializers for those may not be necessary. That's just deleting some unnecessary code from the PR.
• Instead of doing lots of isinstance(), dispatch on the type. This makes it harder to deal with subclasses, though I guess you can do the thing where you get all parent classes and dispatch on each. Though again this'll make it slower, but hopefully not as much. Building on getting parent classes technique, it may be possible to use a little caching so once you've seen a type, you know how to serialize it, so in the common case it's self._prep_for_json[type(obj)](obj) which isn't bad. I'd be OK with this as a second PR, or just filing an issue if you don't want to do it.

Will try to take a deeper look later this week.

[antonkulaga]

I checked and deleted those types that are serialized natively by orjson. It was a bit surprising that for example it could serialize datetime but failed on date and time separately. I do not think that several if-else will significantly slowdown the logging. If we can merge this PR I am open to continue and suggest the separate one with dispatch, but it should be separate PR as it will take time to agree on best apporach

[winternewt]

I'm also having a problem with Paths and other serializations. Wrapping random stuff in str() is tedious, what's missing in this PR for it to be merged? Isn't functools dispatch a bit slower than isinstance chain?

[itamarst]

@winternewt There's nothing stopping you from writing your own serialization code, Eliot has very easy ability to add custom destination for your logs: https://eliot.readthedocs.io/en/stable/outputting/output.html#configuring-logging-output.

[itamarst]

This will get merged when I have some free time.

[itamarst]

Oh, and the FileDestination constructor lets you override the json default function, so you can trivially hook in your own: https://github.com/itamarst/eliot/blob/master/eliot/_output.py#L456

So certainly it would be nicer to have this built-in, but there's really nothing stopping you from customizing JSON serialization in your own code.

[Livia-Zaharia]

Was looking through and found this PR. It could be a pretty useful feature.

[itamarst]

I've created my own branch based on this, going to go work on this now.

[itamarst]

Will re-open PR with new branch when done updating. Thank you for working on this!

[itamarst]

This feature is now released, as part of 1.17.5. Thank you!