galamit86
commented
3 years ago @dkapitan
Trying to implement a decorator logger, I am having trouble understanding what should happen in the decorator, and what in the function itself. More specifically, where do I instantiate a logger object?
Currently, with the basic implementation, I do this:
## statline_bq/utils.py
import logging
# provide logging configuration
LOGGING_CONF_FILE = Path(__file__).parent / "logging_conf.toml"
logging.config.dictConfig(toml.load(LOGGING_CONF_FILE))
# create logger object
logger = logging.getLogger(__name__)
# define some function, and use logger to create the Log Record
def some_func():
# do some things
do_something()
do_something_else()
# log some things
logger.info("This is an INFO log message")My first instinct, was to write this decorator:
## statline_bq/log.py
from pathlib import Path
import functools
import logging
import logging.config
import toml
LOGGING_CONF_FILE = Path(__file__).parent / "logging_conf.toml"
logging.config.dictConfig(toml.load(LOGGING_CONF_FILE))
def logdec(func):
@functools.wraps(func)
def log(*args, **kwargs):
logger = logging.getLogger(func.__module__) #should provide the same as __name__ in the file itself
result = func(*args, **kwargs)
return result
return logNaively hoping that the by replacing the last line of some_func() from logger.info("MESSAGE") to logging.info("MESSAGE"), and decorating it, so it ends up looking like this:
## statline_bq/utils.py
import logging
from statline_bq.log import logdec
# No logger or configuration defined here now
@logdec
def some_func():
# do some things
do_something()
do_something_else()
# log some things
logging.info("This is an INFO log message"), it would use the logger defined in the decorator. But that is not true, as logging.info() simply uses the root logger, and the logger defined in the decorator is not used.
The examples I can find online are always about logging things from "outside" of the function - either because it finished concluded running - like the returned value or a raised exception, or value that are constant to the function - like its name or module. But it seems to me we are looking for something else: we want to log things that are happening inside the function, during normal operation.
I am still working on it, so my problem definition might be off still. But if you have some thoughts or reference to this, let me know.
dkapitan
Implement logging using the standard
loggingmodule:printstatements tologging.SOME_LEVELprefect, throughnl-open-data