public access to logger._context

[radix]

Am I bad for wanting to access logger._context?

Here's my use case: exception logging with extra context from inner frames in the stack.

SLOG = structlog.get_logger()

def erroneous(log, a):
    log = log.bind(a=a)
    try:
        1 / 0
    except Exception as e:
        e._structlog_context = log._context  # This will include `a` and anything else that was already bound to the log
        raise

I don't want to log directly in my exception handler because there's already code higher up the stack which does its own logging:

def main():
    log = SLOG.bind(key="value")
    try:
        cool()
        erroneous(log, 1)
        yeah()
    except Exception as e:
        log.error("oh no", exc_info=True)

Then, I could write a processor that looks for _structlog_context on logged exceptions and return that additional context.

Really, all this exception-handling stuff is kinda orthogonal to request I have, but it shows my motivation. This "extra context on exception" feature could be implemented without being able to access an existing log's context; however, it naturally leads me to want to attach my logger's context to these exceptions, since those loggers are already convenient containers for all the context I want to attach.

So, I'm already doing this in production, but I'm having to access the private _context attribute. Is there some other way to get the context that I missed? Can we have a get_context() method?

[hynek]

I've already promised someone somewhere to keep _context around. Would you agree that structlog.get_context(SLOG) might be the safer bet?

[chiragjn]

+1 for a public method to get the bound context.
For use cases like in OP, I use threadlocal wrapper as the context class to avoid all the passing around. But here is another use case:

We use _context to extract the context and put into request headers to pass it around to other micro-services which gets read and rebound, allowing us to correlate logs across services.

[hynek]

Also: should we return the actual context or a copy? 🤔

[hynek]

I have added it in 33008b0, pls yell if something is missing.

[radix]

Thanks @hynek, sorry I was not around to respond to your comment. This looks perfect.