I've written a python cli with the 'click' library. I'd like to also use python's built-in logging
module for logging to the console. But I've struggled getting the logging messages to the console. I tried a very simple approach:
logger = logging.getLogger(__name__)
@click.command()
def cli():
logger.setLevel("INFO")
logger.info("Does this work?")
print("done.")
The logger content doesn't appear in my console. Maybe it needs a handler to explicitly send log messages to stdout?
logger = logging.getLogger(__name__)
@click.command()
def cli():
handler = logging.StreamHandler(sys.stdout)
handler.setFormatter(logging.Formatter('%(asctime)s %(message)s'))
handler.setLevel("INFO")
logger.addHandler(handler)
logger.info("Does this work?")
print("done.")
Unfortunately this also doesn't work.
A third option--creating a handler and setting loglevels for the handler and the logger-- works:
logger = logging.getLogger(__name__)
@click.command()
def cli():
logger.setLevel("INFO")
handler = logging.StreamHandler(sys.stderr)
handler.setFormatter(logging.Formatter('%(asctime)s %(message)s'))
handler.setLevel("INFO")
logger.addHandler(handler)
logger.info("Does this work?")
print("done.")
It seems like:
logging.getLogger
, I have to create a handler for my logger explicitly.Is that right? It seems silly to set the level twice. What's the point?
Or am I still misunderstanding the right way to do this?
Thanks for your help!
I personally like the loguru
library for handling logs. I think it's simpler.
Here's an example of how I usually do it:
import click
from loguru import logger
@click.command()
@click.option('--count', default=1, help='Number of greetings.')
@click.option('--name', prompt='Your name', help='The person to greet.')
def hello(count, name):
"""Simple program that greets NAME for a total of COUNT times."""
for x in range(count):
logger.info(f"That's it, beautiful and simple logging! - Counter: {x}")
click.echo('Hello %s!' % name)
if __name__ == '__main__':
hello()
❯ python loguru-click-cli-test.py --count=3
Your name: Geraldo
2020-06-10 20:02:48.297 | INFO | __main__:hello:11 - That's it, beautiful and simple logging! - Counter: 0
Hello Geraldo!
2020-06-10 20:02:48.297 | INFO | __main__:hello:11 - That's it, beautiful and simple logging! - Counter: 1
Hello Geraldo!
2020-06-10 20:02:48.297 | INFO | __main__:hello:11 - That's it, beautiful and simple logging! - Counter: 2
Hello Geraldo!
Loguru: https://github.com/Delgan/loguru
I had to manually set
logging.basicConfig(level=logging.INFO)
Example
import click
import logging
logging.basicConfig(level=logging.INFO)
@click.command()
def cli():
logging.info("it works")
gives
$ mycli
INFO:root:it works
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