[roma-frolov]

Description

Fixes #2516

Type of change

• Documentation (typos, code examples, or any documentation updates)
• Bug fix (a non-breaking change that resolves an issue)
• New feature (a non-breaking change that adds functionality)
• Breaking change (a fix or feature that would disrupt existing functionality)
• This change requires a documentation update

Checklist

• My code adheres to the style guidelines of this project (just lint shows no errors)
• I have conducted a self-review of my own code
• I have made the necessary changes to the documentation
• My changes do not generate any new warnings
• I have added tests to validate the effectiveness of my fix or the functionality of my new feature
• Both new and existing unit tests pass successfully on my local environment by running just test-coverage
• I have ensured that static analysis tests are passing by running just static-analysis
• I have included code examples to illustrate the modifications

[roma-frolov]

@draincoder hi!

A similar feature in litestart allows you to pass a Callable that accepts a Request object. Which object is best to pass to FS? AnyMsg?

[Lancetnik]

I think, we can split them in the static init method and cast here without runtime filtering

[roma-frolov]

Did I understand you correctly, you mean this?:

def __init__(
        self,
        msg: AnyMsg | None,
        /,
        *,
        ...,
        static_custom_labels: dict[str, str] | None,
        dynamic_custom_labels: dict[str, Callable[[Any], str]] | None,
) -> None:
    ...
    self._custom_labels = {
        **(static_custom_labels or {}),
        **{k: str(v(msg)) for k, v in (dynamic_custom_labels or {}).items()},
    }
    ...

[Lancetnik]

Nope, I mean

class MiddlewareBuilder:
    def __init__(self, custom_labels):
        self.static_labels = {}
        self.dynamic_labels = {}
        
        for k, v in custom_labels.items():
             if callable(v):
                 self.dynamic_labesl[k] = v
             else:
                 self.static_labesl[k] = v
      
    def __call__(self, msg):
         return RealMiddleware(msg, custom_labels = self.static_labels | {
             k: v(msg) for k, v in self.dynamic_labels.items()
         })

[roma-frolov]

done