FilteringBoundLogger exception() method has different API

[alexcouper]

FilteringBoundLogger exception call fails with positional arguments.

Example

import structlog
from structlog import get_logger
from structlog.stdlib import LoggerFactory

structlog.configure(logger_factory=LoggerFactory())
log = get_logger("test")
log.error("%s %s %s", "bob", "alice", "fred")
log.exception("%s %s %s", "bob", "alice", "fred")

Expected output:

2023-07-15 11:30:42 [error    ] bob alice fred
2023-07-15 11:30:42 [error    ] bob alice fred

Actual output:

2023-07-15 11:30:42 [error    ] bob alice fred
Traceback (most recent call last):
  File "/Users/alex/Work/syndis/aftra/debug/2023-07-13-logging.py", line 30, in <module>
    log.exception("%s %s %s", "bob", "alice", "fred")
TypeError: exception() takes 2 positional arguments but 5 were given

Some historical digging

b71aabb#diff-b87fe76f9eed7fd535af19eade4ac979499ddaaaba4611af36cc59f4b7f247fc introduced the exception method without the *args part of the signature.

That implementation was also later used for the exception method used by FilteringBoundLogger here

A later fix was made to exception to "add pos arg support to exception" here

But no corresponding fix was made to the functions found in _log_levels.py.

Question

Any reason I shouldn't provide a fix, that adjusts the _log_levels.py arguments to include *args and pass them through to the error call?

[alexcouper]

This is the minimum set of configuration needed to make %s style formatting work with the .exception method (afaict):

structlog.configure(
    processors=[
        structlog.stdlib.PositionalArgumentsFormatter(),
        structlog.processors.format_exc_info,
        structlog.stdlib.render_to_log_kwargs,
    ],
    logger_factory=structlog.stdlib.LoggerFactory(),
    wrapper_class=structlog.stdlib.BoundLogger,
)

log = get_logger()
log.info("this is too %s!", "easy")
log.exception("%s %s %s", "bob", "alice", "fred")

Extra info:

• The .info call works straight out of the box with no configuration.
• Changing wrapper_class to structlog.make_filtering_bound_logger(logging.INFO) with the above configuration causes .exception to fail.

[hynek]

Thanks for the digging, that's very helpful!