SoFunction
Updated on 2024-11-20

QA logging in python about third-party logs in detail

Q: python View the current log level

A: In Python, you can use thelogging module to view the current log level.logging module provides a global logging system that contains various configurations and methods that allow you to control the output of the log.

Below is a simple example demonstrating how to view the current log level:

import logging
# Get root logger
logger = ()
# Get the current log level
current_log_level = ()
# Output the current log level
print(f"Current log level: {current_log_level}")
# Set a log level (for demonstration purposes only, you may not need to set a level)
()
# Get the current log level again
current_log_level = ()
# Output updated log levels
print(f"Updated log level: {current_log_level}")

In this example, first use thegetEffectiveLevel() method to get the current log level and print it out. Then, the current level of the log is printed out via thesetLevel() method sets a new log level (in practice, you may not need to set a level, this is just for demonstration purposes). Finally, get the current log level again and print it out.

Please note.getEffectiveLevel() Returns a numeric value, which you can uselogging Constants defined in modules (such as、 etc.) to compare these values to make it easier to understand the log level.

Q: The output value is 30, what does it mean?

A: In Python'slogging In the module, logging levels are represented using integer values that correspond to several predefined constants. These integer values reflect the priority of a log message, from the lowest level of theDEBUG To the highest levelCRITICAL。

Here are some common logging levels and their corresponding integer values:

  • CRITICAL: 50
  • ERROR: 40
  • WARNING (orWARN): 30
  • INFO: 20
  • DEBUG: 10
  • NOTSET: 0

In your code, if the() A return value of 30 indicates that the current log level isWARNING. This means that onlyWARNING、ERROR cap (a poem)CRITICAL level log messages are logged, and theINFO cap (a poem)DEBUG level messages will be ignored.

If you want to output more detailed log information, you can set the log level to a lower value by adjusting it. For example, using the() will enableDEBUG level and above for all log messages.

Q: How to make the logger output to standard output

A: In Python'slogging In the module, logging can be configured to output to different places, one of which is the standard output. Typically, if you want to output logs to standard output, you can do the following configuration:

import logging
# Get root logger
logger = ()
# Create a StreamHandler to output logs to standard output
stream_handler = ()
# Create a formatter, optional, configure as needed
formatter = ('%(levelname)s - %(message)s')
stream_handler.setFormatter(formatter)
# Add StreamHandler to the logger
(stream_handler)
# Set log level, optional, configure as needed
()
# The subsequent log messages will be output to the standard output
("This is a debug message.")
("This is an info message.")
("This is a warning message.")
("This is an error message.")

In the above example, we use the() creates a processor that sends log messages to standard output. We can then pass the(stream_handler) Add this processor to the logger. Finally, we add this processor to the logger via the() The log level is set to ensure that log messages below the specified level are not output.

Please note that this is just a basic configuration example, and you can tweak the format, level, etc. to suit your actual needs.

Q: What is the exc_info parameter for?

A: exc_info be An optional parameter in the grade function that specifies whether to log exception information to the log. When you use the Records a log and includes exception information in that log message.exc_info parameter controls whether detailed exception information (traceback) is included in the log.

following The signature of the function:

(msg, *args, exc_info=False, **kwargs)
  • msg: A log message to be logged, which can contain formatting strings.
  • *args: Parameters used to format the string.
  • exc_info: a boolean if forTrue, then the exception message (traceback) is included in the log. If an exception message for theFalse(default), then no exception information is included.
  • **kwargs: Other optional parameters, such asextra、stack_info etc.

Example use:

import logging
# Get root logger
logger = ()
try:
    # Some of the code that may raise exceptions
    result = 1 / 0
except Exception as e:
    # Record warning level logs and include exception information in the logs
    ("An error occurred: %s", e, exc_info=True)

In this example, theexc_info=True will cause the log to contain detailed exception information, including tracebacks. omitting theexc_info parameter or set it toFalseIf it is not, the log will not contain the exception message.

Note: In general, logging exception information to the log can help you find what went wrong more easily when troubleshooting a problem, but use caution, especially in production environments, as detailed exception information may contain sensitive information.

Q: How to delete all Handlers of all loggers?

A: If you want to delete all handlers for all loggers, you can do it in the following way:

import logging
# Get the names of all existing loggers
existing_loggers = ()
# Iterate over each logger and remove all its handlers
for logger_name in existing_loggers:
    logger = (logger_name)
    handlers = [:]
    for handler in handlers:
        (handler)
        ()

This code first gets the names of all existing loggers, then iterates through each logger and removes all of its handlers, and then calls the() to close each handler and free up any resources that may be occupied.

Note that this removes the handler for all loggers, including any configuration you may have set up previously. If you only want to remove the handler for the root logger, you can use the following code:

import logging
# Get root logger
logger = ()
# Get all handlers of the root logger
handlers = [:]
# Iterate over each handler and delete
for handler in handlers:
    (handler)
    ()

This only removes the handler for the root logger and does not affect other loggers; if you have previously set up handlers for other loggers, they will not be affected.

Q:python View all loggers

A: You can uselogging modular attribute to get the names of all created logger objects. This can be accomplished in the following way:

import logging
# Get the names of all existing loggers
existing_loggers = ()
# Print the names of all loggers
for logger_name in existing_loggers:
    print(logger_name)

The above code first gets the Each key is the name of a logger object. Then, you iterate through the keys, i.e., the logger names, in a loop and print them out.

It is important to note that belogging A global variable in the module that manages all logger objects. This method only fetches loggers that have been created at the current runtime; if you create new loggers in subsequent code, they will also be included.

If you want to get each logger object itself, not just the name, you can use the(logger_name) Methods:

import logging
# Get the names of all existing loggers
existing_loggers = ()
# Get each logger object itself
loggers = [(logger_name) for logger_name in existing_loggers]
# Print each logger object
for logger in loggers:
    print(logger)

This gives you access to all the logger objects that have been created.

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