How to use the logging module in Python-Python Tutorial-php.cn

##1. Low-configuration logging

The logs are divided into the following five levels. These five levels match debug from bottom to top--> info-->warning-->error-->critical, the default lowest level is warning level.

1.v1

import logging

logging.debug(&#39;调试信息&#39;)
logging.info(&#39;正常信息&#39;)
logging.warning(&#39;警告信息&#39;)
logging.error(&#39;报错信息&#39;)
logging.critical(&#39;严重错误信息&#39;)

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WARNING:root:warning message
ERROR:root:error message
CRITICAL:root:serious error message

The v1 version cannot specify the log level; the log format cannot be specified; it can only print to the screen and cannot write to files. Therefore it can be changed to the following code.

2.v2

import logging

# 日志的基本配置

logging.basicConfig(filename=&#39;access.log&#39;,
                    format=&#39;%(asctime)s - %(name)s - %(levelname)s -%(module)s: %(message)s&#39;,
                    datefmt=&#39;%Y-%m-%d %H:%M:%S %p&#39;,
                    level=10)

logging.debug(&#39;调试信息&#39;)  # 10
logging.info(&#39;正常信息&#39;)  # 20
logging.warning(&#39;警告信息&#39;)  # 30
logging.error(&#39;报错信息&#39;)  # 40
logging.critical(&#39;严重错误信息&#39;)  # 50

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You can change the default behavior of the logging module through specific parameters in the logging.basicConfig() function. The available parameters are:

filename: Create a FileHandler with the specified file name (the concept of handler will be explained in detail later), so that the log will be stored in the specified file.
filemode: File opening mode, this parameter is used when filename is specified. The default value is "a" and can also be specified as "w".
format: Specify the log display format used by the handler.
datefmt: Specify the date and time format.
level: Set the log level of the rootlogger (the specific concept will be explained later)
stream: Create a StreamHandler with the specified stream. You can specify the output to sys.stderr, sys.stdout or a file. The default is sys.stderr. If both filename and stream parameters are listed, the stream parameter will be ignored.

Format string that may be used in the format parameter:

%(name)s Logger’s name
%(levelno)s Log level in numeric form
%(levelname)s Log level in text form
% (pathname)s The full path name of the module that calls the log output function, may not be
%(filename)s The file name of the module that calls the log output function
%(module)s The module name that calls the log output function
%(funcName)s The function name that calls the log output function
%(lineno)d The line of code where the statement that calls the log output function is located
%(created)f The current time, expressed as a UNIX standard floating point number representing time
%(relativeCreated)d The number of milliseconds since the Logger was created when outputting log information
%(asctime)s The current value in string form time. The default format is "2003-07-08 16:49:45,896". What follows the comma is the millisecond
%(thread)d thread ID. There may be no
%(threadName)s thread names. There may be no
%(process)d process ID. There may not be
%(message)s messages output by the user.

v2 version cannot specify character encoding; it can only be printed to a file.

3.v3

The logging module contains four roles: logger, Filter, Formatter object, Handler

logger: the object that generates logs
Filter: object for filtering logs
Formatter object: You can customize different log format objects and then bind them to different Handler objects to use This is used to control the log formats of different Handlers
Handler: receives logs and controls printing to different places, FileHandler is used to print to files, StreamHandler is used to print to the terminal

&#39;&#39;&#39;
critical=50
error =40
warning =30
info = 20
debug =10
&#39;&#39;&#39;


import logging

# 1、logger对象：负责产生日志，然后交给Filter过滤，然后交给不同的Handler输出
logger = logging.getLogger(__file__)

# 2、Filter对象：不常用，略

# 3、Handler对象：接收logger传来的日志，然后控制输出
h2 = logging.FileHandler(&#39;t1.log&#39;)  # 打印到文件
h3 = logging.FileHandler(&#39;t2.log&#39;)  # 打印到文件
sm = logging.StreamHandler()  # 打印到终端

# 4、Formatter对象：日志格式
formmater1 = logging.Formatter(&#39;%(asctime)s - %(name)s - %(levelname)s -%(module)s:  %(message)s&#39;,
                               datefmt=&#39;%Y-%m-%d %H:%M:%S %p&#39;,)

formmater2 = logging.Formatter(&#39;%(asctime)s :  %(message)s&#39;,
                               datefmt=&#39;%Y-%m-%d %H:%M:%S %p&#39;,)

formmater3 = logging.Formatter(&#39;%(name)s %(message)s&#39;,)


# 5、为Handler对象绑定格式
h2.setFormatter(formmater1)
h3.setFormatter(formmater2)
sm.setFormatter(formmater3)

# 6、将Handler添加给logger并设置日志级别
logger.addHandler(h2)
logger.addHandler(h3)
logger.addHandler(sm)

# 设置日志级别，可以在两个关卡进行设置logger与handler
# logger是第一级过滤，然后才能到handler
logger.setLevel(30)
h2.setLevel(10)
h3.setLevel(10)
sm.setLevel(10)

# 7、测试
logger.debug(&#39;debug&#39;)
logger.info(&#39;info&#39;)
logger.warning(&#39;warning&#39;)
logger.error(&#39;error&#39;)
logger.critical(&#39;critical&#39;)

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2. High configuration logging

1. Configuration log file

The above three versions of logs are just to lead to our following log configuration file

import os
import logging.config

# 定义三种日志输出格式 开始
standard_format = &#39;[%(asctime)s][%(threadName)s:%(thread)d][task_id:%(name)s][%(filename)s:%(lineno)d]&#39; \
                  &#39;[%(levelname)s][%(message)s]&#39;  # 其中name为getLogger()指定的名字；lineno为调用日志输出函数的语句所在的代码行
simple_format = &#39;[%(levelname)s][%(asctime)s][%(filename)s:%(lineno)d]%(message)s&#39;
id_simple_format = &#39;[%(levelname)s][%(asctime)s] %(message)s&#39;
# 定义日志输出格式 结束

logfile_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))  # log文件的目录，需要自定义文件路径 # atm
logfile_dir = os.path.join(logfile_dir, &#39;log&#39;)  # C:\Users\oldboy\Desktop\atm\log

logfile_name = &#39;log.log&#39;  # log文件名，需要自定义路径名

# 如果不存在定义的日志目录就创建一个
if not os.path.isdir(logfile_dir):  # C:\Users\oldboy\Desktop\atm\log
    os.mkdir(logfile_dir)

# log文件的全路径
logfile_path = os.path.join(logfile_dir, logfile_name)  # C:\Users\oldboy\Desktop\atm\log\log.log
# 定义日志路径 结束

# log配置字典
LOGGING_DIC = {
    &#39;version&#39;: 1,
    &#39;disable_existing_loggers&#39;: False,
    &#39;formatters&#39;: {
        &#39;standard&#39;: {
            &#39;format&#39;: standard_format
        },
        &#39;simple&#39;: {
            &#39;format&#39;: simple_format
        },
    },
    &#39;filters&#39;: {},  # filter可以不定义
    &#39;handlers&#39;: {
        # 打印到终端的日志
        &#39;console&#39;: {
            &#39;level&#39;: &#39;DEBUG&#39;,
            &#39;class&#39;: &#39;logging.StreamHandler&#39;,  # 打印到屏幕
            &#39;formatter&#39;: &#39;simple&#39;
        },
        # 打印到文件的日志,收集info及以上的日志
        &#39;default&#39;: {
            &#39;level&#39;: &#39;INFO&#39;,
            &#39;class&#39;: &#39;logging.handlers.RotatingFileHandler&#39;,  # 保存到文件
            &#39;formatter&#39;: &#39;standard&#39;,
            &#39;filename&#39;: logfile_path,  # 日志文件
            &#39;maxBytes&#39;: 1024 * 1024 * 5,  # 日志大小 5M  (*****)
            &#39;backupCount&#39;: 5,
            &#39;encoding&#39;: &#39;utf-8&#39;,  # 日志文件的编码，再也不用担心中文log乱码了
        },
    },
    &#39;loggers&#39;: {
        # logging.getLogger(__name__)拿到的logger配置。如果&#39;&#39;设置为固定值logger1，则下次导入必须设置成logging.getLogger(&#39;logger1&#39;)
        &#39;&#39;: {
            # 这里把上面定义的两个handler都加上，即log数据既写入文件又打印到屏幕
            &#39;handlers&#39;: [&#39;default&#39;, &#39;console&#39;],
            &#39;level&#39;: &#39;DEBUG&#39;,
            &#39;propagate&#39;: False,  # 向上（更高level的logger）传递
        },
    },
}



def load_my_logging_cfg():
    logging.config.dictConfig(LOGGING_DIC)  # 导入上面定义的logging配置
    logger = logging.getLogger(__name__)  # 生成一个log实例
    logger.info(&#39;It works!&#39;)  # 记录该文件的运行状态
    
    return logger


if __name__ == &#39;__main__&#39;:
    load_my_logging_cfg()

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2. Usage log

import time
import logging
import my_logging  # 导入自定义的logging配置

logger = logging.getLogger(__name__)  # 生成logger实例


def demo():
    logger.debug("start range... time:{}".format(time.time()))
    logger.info("中文测试开始。。。")
    for i in range(10):
        logger.debug("i:{}".format(i))
        time.sleep(0.2)
    else:
        logger.debug("over range... time:{}".format(time.time()))
    logger.info("中文测试结束。。。")


if __name__ == "__main__":
    my_logging.load_my_logging_cfg()  # 在你程序文件的入口加载自定义logging配置
    demo()

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3. Django log configuration file

# logging_config.py
# 学习中遇到问题没人解答？小编创建了一个Python学习交流群：711312441
LOGGING = {
    &#39;version&#39;: 1,
    &#39;disable_existing_loggers&#39;: False,
    &#39;formatters&#39;: {
        &#39;standard&#39;: {
            &#39;format&#39;: &#39;[%(asctime)s][%(threadName)s:%(thread)d][task_id:%(name)s][%(filename)s:%(lineno)d]&#39;
                      &#39;[%(levelname)s][%(message)s]&#39;
        },
        &#39;simple&#39;: {
            &#39;format&#39;: &#39;[%(levelname)s][%(asctime)s][%(filename)s:%(lineno)d]%(message)s&#39;
        },
        &#39;collect&#39;: {
            &#39;format&#39;: &#39;%(message)s&#39;
        }
    },
    &#39;filters&#39;: {
        &#39;require_debug_true&#39;: {
            &#39;()&#39;: &#39;django.utils.log.RequireDebugTrue&#39;,
        },
    },
    &#39;handlers&#39;: {
        # 打印到终端的日志
        &#39;console&#39;: {
            &#39;level&#39;: &#39;DEBUG&#39;,
            &#39;filters&#39;: [&#39;require_debug_true&#39;],
            &#39;class&#39;: &#39;logging.StreamHandler&#39;,
            &#39;formatter&#39;: &#39;simple&#39;
        },
        # 打印到文件的日志,收集info及以上的日志
        &#39;default&#39;: {
            &#39;level&#39;: &#39;INFO&#39;,
            &#39;class&#39;: &#39;logging.handlers.RotatingFileHandler&#39;,  # 保存到文件，自动切
            &#39;filename&#39;: os.path.join(BASE_LOG_DIR, "xxx_info.log"),  # 日志文件
            &#39;maxBytes&#39;: 1024 * 1024 * 5,  # 日志大小 5M
            &#39;backupCount&#39;: 3,
            &#39;formatter&#39;: &#39;standard&#39;,
            &#39;encoding&#39;: &#39;utf-8&#39;,
        },
        # 打印到文件的日志:收集错误及以上的日志
        &#39;error&#39;: {
            &#39;level&#39;: &#39;ERROR&#39;,
            &#39;class&#39;: &#39;logging.handlers.RotatingFileHandler&#39;,  # 保存到文件，自动切
            &#39;filename&#39;: os.path.join(BASE_LOG_DIR, "xxx_err.log"),  # 日志文件
            &#39;maxBytes&#39;: 1024 * 1024 * 5,  # 日志大小 5M
            &#39;backupCount&#39;: 5,
            &#39;formatter&#39;: &#39;standard&#39;,
            &#39;encoding&#39;: &#39;utf-8&#39;,
        },
        # 打印到文件的日志
        &#39;collect&#39;: {
            &#39;level&#39;: &#39;INFO&#39;,
            &#39;class&#39;: &#39;logging.handlers.RotatingFileHandler&#39;,  # 保存到文件，自动切
            &#39;filename&#39;: os.path.join(BASE_LOG_DIR, "xxx_collect.log"),
            &#39;maxBytes&#39;: 1024 * 1024 * 5,  # 日志大小 5M
            &#39;backupCount&#39;: 5,
            &#39;formatter&#39;: &#39;collect&#39;,
            &#39;encoding&#39;: "utf-8"
        }
    },
    &#39;loggers&#39;: {
        # logging.getLogger(__name__)拿到的logger配置
        &#39;&#39;: {
            &#39;handlers&#39;: [&#39;default&#39;, &#39;console&#39;, &#39;error&#39;],
            &#39;level&#39;: &#39;DEBUG&#39;,
            &#39;propagate&#39;: True,
        },
        # logging.getLogger(&#39;collect&#39;)拿到的logger配置
        &#39;collect&#39;: {
            &#39;handlers&#39;: [&#39;console&#39;, &#39;collect&#39;],
            &#39;level&#39;: &#39;INFO&#39;,
        }
    },
}


# -----------
# 用法:拿到俩个logger

logger = logging.getLogger(__name__)  # 线上正常的日志
collect_logger = logging.getLogger("collect")  # 领导说,需要为领导们单独定制领导们看的日志

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