Python 日志记录-loguru

Python 日志记录-loguru

使用logging模块时

用python写代码时，logging模块最基本的几行配置，如下：

import logging
logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(name)s - %(levelname)s - %(message)s')
logger = logging.getLogger(__name__)

logger.info('this is another debug message')
logger.warning('this is another debug message')
logger.error('this is another debug message')
logger.info('this is another debug message')

执行结果如下：

引言 loguru

如果想更简洁，可用loguru库

loguru默认的输出格式是上面的内容，有时间、级别、模块名、行号以及日志信息，不需要手动创建 logger，直接使用即可，另外其输出还是彩色的，看起来会更加友好。

官方文档

• GitHub - Delgan/loguru: Python logging made (stupidly) simple
• loguru.logger — loguru documentation

安装

pip install loguru
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日志级别

Level name	Severity value	Logger method
TRACE	5	logger.trace
DEBUG	10	logger.debug
INFO	20	logger.info
SUCCESS	25	logger.success
WARNING	30	logger.warning
ERROR	40	logger.error
CRITICAL	50	logger.critical

简单测试下

from loguru import logger

logger.debug("debug")
logger.info("info")
logger.success("success")
logger.warning("warning")
logger.error("error")
logger.critical("critical")
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输出结果

logger.add()
#参数：
　　sys.stdout-在控制台输出，如果不想在控制台输出，直接写文件名即可 ../haha.log
　　level:日志的级别。 debug，info，warning，error
　　encoding='utf-8' 如果输出日志到文件中时，需要指定此参数
　　format:日志的输出格式'[{time}][{level}][{file}:line{line}:function_name:{function}] || mesg = {message}'
　　enqueue：什么方式写日志 True为异步，false为同步
　　rotation：超过多少就生成一个新的日志文件，可设置大小
　　retention：多长时间后会删除以前产生的日志，当前的日志不会受影响

特性

简介

此函数应用于注册接收器，这些接收器负责管理使用记录字典上下文化的日志消息。接收器可以采用多种形式：简单函数、字符串路径、类似文件的对象、协程函数或内置处理程序。

请注意：可以使用remove()函数来删除以前添加的处理程序。

例子：

import sys
from loguru import logger


logger.add("test.log", format="{time} {level} {message}", filter="", level="INFO", encoding="utf-8")
logger.debug("debug")
logger.info("info")
logger.success("success")
logger.warning("warning")
logger.error("error")
logger.critical("critical")
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效果，输出日志到test.log文件

2022-07-27T17:14:36.393072+0800 INFO info
2022-07-27T17:14:36.394068+0800 SUCCESS success
2022-07-27T17:14:36.395066+0800 WARNING warning
2022-07-27T17:14:36.396063+0800 ERROR error
2022-07-27T17:14:36.397060+0800 CRITICAL critical
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rotation/retension/compression

官方介绍：loguru.logger — loguru documentation

rotation:指示何时应关闭当前记录的文件并创建新文件,可以是文件大小/每天的时间点/时间间隔等。

logger.add("test1.log", rotation="500 MB") # 日志文件超过500M创建新的文件
logger.add("test2.log", rotation="12:00")  # 每天中午12点创建新的日志文件
logger.add("test3.log", rotation="1 week") # 当前使用的日志文件超过1周，创建新的日志文件
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retension:指示合适应该删除旧文件。

logger.add("test4.log", retention="10 days") # 超过十天的日志文件删除
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compression:日志文件在关闭时应转换为的压缩或归档格式。

logger.add("test5.log", compression="zip") # 日志文件关闭后，使用zip进行压缩
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50m一个文件，保留3个文件
logger.add('sync_inc.log', level='INFO', encoding="utf-8", rotation="50 MB", retention=3)

异常捕获

使用catch()装饰器或者上下文管理器可以捕获异常，确保任何错误都能够记录到log日志中。

装饰器

from loguru import logger

@logger.catch
def test(x, y, z):
    return 1 / (x + y + z)
test(0, 1, -1)
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上下文装饰器

from loguru import logger


def test(x, y, z):
    return 1 / (x + y + z)
with logger.catch():
    test(0, 1, -1) 
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输出结果

完全描述性异常

记录代码中发生的异常对于跟踪BUG非常重要，loguru允许显示整个堆栈跟踪（包括变量值）来帮助定位BUG原因。

logger.add("out.log", backtrace=True, diagnose=True)  # Caution, may leak sensitive data in prod

def func(a, b):
    return a / b
def nested(c):
    try:
        func(5, c)
    except ZeroDivisionError:
        logger.exception("What?!")
nested(0)
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输出结果

自定义颜色

logger.add(sys.stdout, colorize=True, format="<red>{time}</red> <level>{message}</level>")
logger.debug("debug")
logger.info("info")
logger.success("success")
logger.warning("warning")
logger.error("error")
logger.critical("critical")
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输出结果

异步/线程安全/多进程安全

默认情况下，添加到log的所有接收器都是线程安全的，但他们不是多进程安全的。如果需要实现多进程安全，异步记录日志，需要添加一个enqueue参数：

logger.add("test.log", enqueue = True)
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结构化日志记录

将消息转化为json字符串以便于传递或者解析，可以使用serialize来配置：

logger.add("test.log", serialize=True, encoding="utf-8")
logger.debug("debug")
logger.info("info")
logger.success("success")
logger.warning("warning")
logger.error("error")
logger.critical("critical")
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输出结果

{"text": "2022-07-28 11:25:44.434 | DEBUG    | __main__:<module>:43 - debug\n", "record": {"elapsed": {"repr": "0:00:00.127658", "seconds": 0.127658}, "exception": null, "extra": {}, "file": {"name": "logutil.py", "path": "e:\\GitPorject\\ZanguS1\\ZanguRecorder\\common\\logutil.py"}, "function": "<module>", "level": {"icon": "🐞", "name": "DEBUG", "no": 10}, "line": 43, "message": "debug", "module": "logutil", "name": "__main__", "process": {"id": 15768, "name": "MainProcess"}, "thread": {"id": 10228, "name": "MainThread"}, "time": {"repr": "2022-07-28 11:25:44.434074+08:00", "timestamp": 1658978744.434074}}}
{"text": "2022-07-28 11:25:44.436 | INFO     | __main__:<module>:44 - info\n", "record": {"elapsed": {"repr": "0:00:00.129653", "seconds": 0.129653}, "exception": null, "extra": {}, "file": {"name": "logutil.py", "path": "e:\\GitPorject\\ZanguS1\\ZanguRecorder\\common\\logutil.py"}, "function": "<module>", "level": {"icon": "ℹ️", "name": "INFO", "no": 20}, "line": 44, "message": "info", "module": "logutil", "name": "__main__", "process": {"id": 15768, "name": "MainProcess"}, "thread": {"id": 10228, "name": "MainThread"}, "time": {"repr": "2022-07-28 11:25:44.436069+08:00", "timestamp": 1658978744.436069}}}
{"text": "2022-07-28 11:25:44.438 | SUCCESS  | __main__:<module>:45 - success\n", "record": {"elapsed": {"repr": "0:00:00.131648", "seconds": 0.131648}, "exception": null, "extra": {}, "file": {"name": "logutil.py", "path": "e:\\GitPorject\\ZanguS1\\ZanguRecorder\\common\\logutil.py"}, "function": "<module>", "level": {"icon": "✔️", "name": "SUCCESS", "no": 25}, "line": 45, "message": "success", "module": "logutil", "name": "__main__", "process": {"id": 15768, "name": "MainProcess"}, "thread": {"id": 10228, "name": "MainThread"}, "time": {"repr": "2022-07-28 11:25:44.438064+08:00", "timestamp": 1658978744.438064}}}
{"text": "2022-07-28 11:25:44.439 | WARNING  | __main__:<module>:46 - warning\n", "record": {"elapsed": {"repr": "0:00:00.132645", "seconds": 0.132645}, "exception": null, "extra": {}, "file": {"name": "logutil.py", "path": "e:\\GitPorject\\ZanguS1\\ZanguRecorder\\common\\logutil.py"}, "function": "<module>", "level": {"icon": "⚠️", "name": "WARNING", "no": 30}, "line": 46, "message": "warning", "module": "logutil", "name": "__main__", "process": {"id": 15768, "name": "MainProcess"}, "thread": {"id": 10228, "name": "MainThread"}, "time": {"repr": "2022-07-28 11:25:44.439061+08:00", "timestamp": 1658978744.439061}}}
{"text": "2022-07-28 11:25:44.440 | ERROR    | __main__:<module>:47 - error\n", "record": {"elapsed": {"repr": "0:00:00.133642", "seconds": 0.133642}, "exception": null, "extra": {}, "file": {"name": "logutil.py", "path": "e:\\GitPorject\\ZanguS1\\ZanguRecorder\\common\\logutil.py"}, "function": "<module>", "level": {"icon": "❌", "name": "ERROR", "no": 40}, "line": 47, "message": "error", "module": "logutil", "name": "__main__", "process": {"id": 15768, "name": "MainProcess"}, "thread": {"id": 10228, "name": "MainThread"}, "time": {"repr": "2022-07-28 11:25:44.440058+08:00", "timestamp": 1658978744.440058}}}
{"text": "2022-07-28 11:25:44.442 | CRITICAL | __main__:<module>:48 - critical\n", "record": {"elapsed": {"repr": "0:00:00.135637", "seconds": 0.135637}, "exception": null, "extra": {}, "file": {"name": "logutil.py", "path": "e:\\GitPorject\\ZanguS1\\ZanguRecorder\\common\\logutil.py"}, "function": "<module>", "level": {"icon": "☠️", "name": "CRITICAL", "no": 50}, "line": 48, "message": "critical", "module": "logutil", "name": "__main__", "process": {"id": 15768, "name": "MainProcess"}, "thread": {"id": 10228, "name": "MainThread"}, "time": {"repr": "2022-07-28 11:25:44.442053+08:00", "timestamp": 1658978744.442053}}}
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使用bind()添加额外的属性：

logger.add("test.log", format="{extra[ip]} {extra[user]} {message}")
context_logger = logger.bind(ip="192.168.0.1", user="someone")
context_logger.info("Contextualize your logger easily")
context_logger.bind(user="someone_else").info("Inline binding of extra attribute")
context_logger.info("Use kwargs to add context during formatting: {user}", user="anybody")
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输出结果

192.168.0.1 someone Contextualize your logger easily
192.168.0.1 someone_else Inline binding of extra attribute
192.168.0.1 anybody Use kwargs to add context during formatting: anybody
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使用bind()和filter对日志进行过滤：

logger.add("test.log", filter=lambda record: "special" in record["extra"])
logger.debug("This message is not logged to the file")
logger.bind(special=True).info("This message, though, is logged to the file!")
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输出结果

2022-07-28 11:33:58.214 | INFO     | __main__:<module>:58 - This message, though, is logged to the file!
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自定义级别

Loguru 附带了所有标准日志记录级别，额外添加了trace和success。如果需要自定义级别，可以使用level()函数来创建：

new_level = logger.level("test2", no=66, color="<black>", icon="🐍")

logger.log("test2", "Here we go!")
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输出结果：

日期时间处理

logger.add("test.log", format="{time:YYYY-MM-DD at HH:mm:ss} | {level} | {message}")
logger.debug("debug")
logger.info("info")
logger.success("success")
logger.warning("warning")
logger.error("error")
logger.critical("critical")
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输出结果：

2022-07-28 at 11:41:32 | DEBUG | debug
2022-07-28 at 11:41:32 | INFO | info
2022-07-28 at 11:41:32 | SUCCESS | success
2022-07-28 at 11:41:32 | WARNING | warning
2022-07-28 at 11:41:32 | ERROR | error
2022-07-28 at 11:41:32 | CRITICAL | critical
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loguru配置

在脚本中使用记录器很容易，您可以在开始时configure()它。要从库中使用 Loguru，请记住永远不要调用 add()，而是使用 disable()，以便日志记录函数变为 no-op。如果开发人员希望查看库的日志，他可以再次enable() 它。

# For scripts
config = {
    "handlers": [
        {"sink": sys.stdout, "format": "{time} - {message}"},
        {"sink": "test.log", "serialize": True},
    ],
    "extra": {"user": "someone"}
}
logger.configure(**config)

# For libraries
logger.disable("my_library")
logger.info("No matter added sinks, this message is not displayed")
logger.enable("my_library")
logger.info("This message however is propagated to the sinks")
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通知程序

Loguru 可以和强大的邮件通知模块 notifiers 库结合使用，以在程序意外失败时接收电子邮件，或发送许多其他类型的通知。

import notifiers

params = {
    "username": "you@gmail.com",
    "password": "abc123",
    "to": "dest@gmail.com"
}
# Send a single notification
notifier = notifiers.get_notifier("gmail")
notifier.notify(message="The application is running!", **params)
# Be alerted on each error message
from notifiers.logging import NotificationHandler
handler = NotificationHandler("gmail", defaults=params)
logger.add(handler, level="ERROR")
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尾语

希望能帮助到大家，如果又说的不对的地方，欢迎大家指正。