Logging custom docs

[euri10]

attempt at solving #491

It adds a simple example of an app with custom logging

I added markdown-include so that examples are code, it could be a good idea to add to the tests CI that part of the docs

[tomchristie]

Great work getting started on this!

It'd be great if we could make this a bit more minimal. In particular:

• It'd be helpful to just give an example logging config file that replicates the existing default log config.
• It'd be nice if the only things that changed in the PR were (1) Adding an example log config file. and (2) linking to it from the settings docs.

I'd prefer it if we could drop all the other surrounding context.

[euri10]

ok I made the logging_example.yml replicate the default config the only difference being it's a yaml file and not a dict
I kept markdown-include addition but I can remove it, it just makes things simpler imho in the case we put a yaml file as a config, any change in it will be automatically reflected in the docs, but I understand if you'd prefer not to.

Next slash in the PR could be to just copy/paste the LOGGING_CONFIG dictionnary into a file and link it in the settings page, that;d more minimal, let me know what you prefer :)

[tomchristie]

I'd rather than any example is just included directly, than using this style.

[euri10]

ok so you prefer to remove markdown-include and just copy-paste examples right ?

[tomchristie]

Yup

[euri10]

done

[tomchristie]

Just checking... Does this definately work?
I haven't checked out if Python's log file format also supports using the yaml style?

[euri10]

this is definitely an ambiguous formulation, python logging supports dict / file (ini style). A lot of time people use yaml and load it to dict with pyyaml for instance, that's why I said "representation"

[tomchristie]

Right, but it wouldn't directly work with our --log-config flag right?

(Tho we could potentially change things here, so that we expect a YAML style logging config file.)

[euri10]

correct, one would have to do something like

    with open('logging_example.yaml', 'r') as stream:
        config = yaml.load(stream, yaml.FullLoader)
    uvicorn.run("main:app", reload=True, log_config=config, log_level="trace")