Add ability to reconfigure a Logfire object

[alxwrd-gelt]

Description

It would be useful to be able to reconfigure a Logfire object.

Right now, any call to .configure() needs to be aware of the full configuration for the logging and can't just update/reconfigure certain aspects. This can be problematic when needing to just update one aspect of the logger, like when testing.

For example, if I want to add a test exporter for tests

# app.py
import logfire

logfire.configure(
    scrubbing=logfire.ScrubbingOptions()
)

def main():
    logfire.info(...)

# test.py
import logfire
from logfire.testing import SimpleSpanProcessor, TestExporter

from app import main

def test_scrubbing():
    exporter = TestExporter()

    logfire.configure(
        scrubbing=logfire.ScrubbingOptions(),
        additional_span_processors=[SimpleSpanProcessor(exporter)],
    )

    main()

Here, Logire was already configured in app.py. I want to test my scrubber but I need to reconfigure it in the test. logfire.reconfigure would allow me to just pass additional_span_processors.

---

There is option of using capfire, but that has the inverse problem.

# test.py
import logfire
from logfire.testing import CaptureLogfire

from app import main

def test_scrubbing(capfire: CaptureLogfire):
    exporter = TestExporter()

    logfire.configure(
        scrubbing=logfire.ScrubbingOptions(),
        additional_span_processors=[SimpleSpanProcessor(exporter)],
    )

    main()

This time, the capfire fixture has made a call to logfire.configure(), overwriting the configuration from app.py. In order to add the scrubbing back in, I also need to configure my own test exporter. logfire.reconfigure would allow me to just pass scrubbing.

[pipinstalled]

@alexmojaki can i work on this?

[alexmojaki]

Multiple global calls to logfire.configure outside of tests is discouraged. What about capfire.reconfigure?