In python, is there any way to set the LOG level based on the logger's name?

Let's consider a python3 package called "foo". I have defined a root logger, a stream handler and each time I create a logger in different modules I call logging.getLogger(__ name__).
I use some third-party libraries too.

I was expecting only to see my own logs with logger names such as "foo.A". But, in addition to those logs, I am also getting third-party logs of the libraries with loggers names such as: "urllib3.connectionpool" or "asyncio".

I would like to be able to set the LOG level of those loggers.

I have tried to create parent loggers for those and set the log level one by one. For example:

urllib3_logger = logging.getLogger("urllib3")
urllib3_logger.setLevel("WARNING")

It works, but I would like to use some kind of regex to do it for every logger. For example set "WARNING" level for any logger for whose name does not start with "foo".

Do you have any idea how could I achieve this?

logging library doesn't directly support regular expressions for logger names, we could set the root logger's level to WARNING and then set your application's logger level to a lower level, something like the following

import logging

root_logger = logging.getLogger()
root_logger.setLevel(logging.WARNING)

my_logger = logging.getLogger('foo')
my_logger.setLevel(logging.INFO)

third_party_logger = logging.getLogger('urllib3')

handler = logging.StreamHandler()
root_logger.addHandler(handler)
my_logger.addHandler(handler)
third_party_logger.addHandler(handler)

my_logger.info("This will print because its level is INFO")
third_party_logger.info("This will not print because its level is WARNING")

Here is a little demo, it assumes:

• the only logger with a handler (or handlers) is the
  root logger
• all ohter loggers are created with 'propagate' set to true
  (this is the default)

Then all messages are emitted with the root logger's handler and you can add a filter to that handler (not to the logger, it won't be called for propagated messages)

import logging

def rootfilter(record):
    name = record.name
    if name == 'foo' or name.startswith('foo.'):
        level = logging.DEBUG
    else:
        level = logging.WARNING
    # --testing only--
    if record.levelno < level:
        print(f"rejecting {record}")
    # --end--
    return record.levelno >= level

root_logger = logging.getLogger()
root_logger.setLevel(logging.DEBUG)
handler = logging.StreamHandler()
handler.addFilter(rootfilter)
root_logger.addHandler(handler)

my_logger = logging.getLogger('foo')
other_logger = logging.getLogger('other')

my_logger.info("foo INFO")
other_logger.info("other INFO")
other_logger.warning("other WARNING")