✨ Support --log-config option

[07pepa]

sometimes its nice to have your custom logging in fastapi so i added passing it to uvicorn and fallbacking to uvicorn default one if nothing is passed in

[Leon0824]

+1

[FelixBehne]

+1

[wchaws]

+1

[saligrama]

+1

[ghost]

+1

[vitaliy-sk]

+1

[LoopKarma]

Can you please help this feature to go through @tiangolo? it's very annoying to see unnecessary access logs in production servers

[darowny]

+1 I need ECS logging for fastapi run

[Morry98]

+1 i really need to change the uvicorn log level because some path like readiness and liveness in k8s are called every few seconds and the exception will "disappear" inside the logs after few minutes.
(also the possibility to have change the log only for specific paths should be nice. don't know if uvicorn support something similar or should be done in fastapi code)

[agbrettpittman]

+1 I also need this as the default logger doesn't have timestamps. When errors occur, it makes troubleshooting much more difficult. There are workarounds, but being able to specify a logging override would be the easiest method.

[sanderbollen-clockworks]

I too would love to be able to override the logger - I'd like to be able to use the same formatter that's used for my application code. Especially the lack of timestamps for access logs is quite annoying.

[CostcoFanboy]

+1, imo this is what stops this wrapper from being genuinely production-ready.

[Morry98]

Following up on my previous comment saying that after some studies I will suggest for production service to avoid fastapi-cli installing fastapi and uvicorn without fastapi[standard] or other versions.

You can create the main.py file with explicit uvicorn configuration:

import uvicorn

uvicorn.run(
    "app_folder.app_creator:app",
    host=<host>,  # example: "0.0.0.0"
    port=<port>,  # example: 8080
    workers=<workers>,  # example: 3
    reload=<reload>,  # false in production
    log_config=<logging_config dict> # Optional
)

• I suggest to use pydantic-settings to create a configuration object containing all the parameters in order to be flexible with different configuration sources having a type validation
• logging_config dict follow the python logging standard configuration that can be found here. In this way you can have a clean cli that is much readable server-side and you can set up other handlers like jsonl file or more fancy handlers. In my case I set up a clean and minimal cli log without fancy lines and similar stuff, plus a jsonl like handler that split the file by level and rotate them, all the handlers managed by a queue handler that process them in a separated thread in order to avoid api performance issues.

In app_creator.py create your FastAPI app with all necessary components like lifespan, routers, middleware etc.
Something similar to:

from fastapi import FastAPI

app = FastAPI(
    title="Your API",
    # all needed parameters and configurations
)

# Add routers, middleware, exception handlers, etc.
app.include_router(your_router)

[Copilot]

Pull request overview

This PR adds support for custom logging configuration in FastAPI CLI by allowing users to pass a --log-config option to both fastapi dev and fastapi run commands. The implementation properly falls back to uvicorn's default logging configuration when no custom config is provided.

Key changes:

• Added --log-config parameter to dev and run CLI commands that accepts a Path to a logging configuration file
• Updated _run function to accept and conditionally use custom log config, falling back to get_uvicorn_log_config() when not provided
• Added comprehensive test coverage including argument validation and help text verification

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/fastapi_cli/cli.py	Added log_config parameter to _run, dev, and run functions with conditional logic to use custom config or fall back to default
tests/test_cli.py	Added test cases verifying --log-config argument is properly passed to uvicorn and help text is correctly displayed
tests/assets/log_config.yaml	Added sample logging configuration file for testing purposes with standard Python logging dict config format

---

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[07pepa]

@YuriiMotov Sorry to spam you.

Can i ask you to add Feature label like it was done for #160
and leave further decision on Sebastian ?

Thank you

[YuriiMotov]

LGTM!
@07pepa, thanks!

As we don't have exist=True parameter, we don't actually need to add the tests/assets/log_config.yaml file.
But it will be needed if we decide to add exist=True.

[YuriiMotov]

We can also specify:

Suggested change

	),
	dir_okay=False,
	exists=True,
	),

(and the same for run command)