> For the complete documentation index, see [llms.txt](https://docs.xiwind-corp.com/tech/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.xiwind-corp.com/tech/python-library/logging-ri-zhi.md). # logging 【日誌】 ## Logging *** Logging library module 允許開發人員將日誌功能整合到他們的應用程序中，從而在運行時記錄事件、錯誤和其他重要信息。
Logging library module

Logging library module

`print()` 是沒有嚴重性概念的普通文本。而 Logging 具有 4 個級別的日誌訊息嚴重性或重要性，有助於從訊息忽略較低嚴重性的訊息。
Log 級別說明
info(msg, *args, **kwargs)監視和理解應用程序行為。(例如: 報告流程、事件、顯示狀態)
debug(msg, *args, **kwargs)用於開發和測試階段。(例如: 記錄變數值、路徑、內部狀態)
warning(msg, *args, **kwargs)表示問題已經發生或即將發生，但應用程序仍可以繼續運行。
error(msg, *args, **kwargs)表示特定操作或任務失敗或遇到異常。錯誤通常會阻止應用程序按預期運行或產生不正確的結果。
critical(msg, *args, **kwargs)表示對應用程序的功能有重大的嚴重錯誤。當此類事件發生時，應用程序可能處於不穩定或不可恢復的狀態。
{% code title="PYTHON" %} ```python import logging # log logging.info("[This is a info]") logging.warning("[This is a warning]") logging.error("[This is a error]") logging.critical("[This is a critical]") ``` {% endcode %} **執行結果** ```TXT WARNING:root:[This is a warning] ERROR:root:[This is a error] CRITICAL:root:[This is a critical] ``` ### 最佳的紀錄工具 ***
任務工具
顯示在 Terminalprint()
監控或故障調查logging.info()、 logging.debug()
發出事件的警告logging.warning()(注意該事件)、warnings.warn()；(必須修正該事件)
報告事件的錯誤引發 Exception。詳見: [[exception 【異常】]]
抑制錯誤而不引發異常
(例如: 伺服器中的 Threading)		logging.error(), logging.exception(), logging.critical()
## basicConfig *** **快速設定多個屬性** (logger、FileHandler...) {% code title="PYTHON" %} ```python logging.basicConfig(**kwargs) ``` {% endcode %} 常用的參數：
輸出級別控制說明
filename寫入日誌訊息的檔案名稱，否則輸出在 Terminal。
filemode寫入模式，即 open()。如果指定 filename，則使用 "a"。
format需要寫入的日誌訊息。詳見: LogRecord attributes。
datefmt指定的日期/時間格式。與 time.strftime() 的格式相同。
style日誌訊息的格式('%', '{', '$')，預設為%。
level設置根記錄器級別，不會記錄較小的級別的日誌。級別大小為: DEBUG < INFO < WARNING < ERROR < CRITICAL。
encoding編碼模式。常使用 encoding="UTF-8"。
### fileConfig `fileConfig()` 允許使用 Configuration file 設定日誌記錄，而不是透過程式碼的方式定義。 支持的格式有：.ini、.yaml、.json。 透過使用 `logging.config.fileConfig()`，您可以將日誌記錄設定與您的程式碼分開，從而在不修改代碼本身的情況下更輕鬆地管理。此外，您可以為不同的環境或模塊使用不同的 Configuration file。 {% code title="PYTHON" %} ```python logging.config.fileConfig(fname, defaults=None, disable_existing_loggers=True, encoding=None) ``` {% endcode %} ## Logger *** 建立 Logger ，可以過濾 log 資訊。 **設定 Logger。** {% code title="PYTHON" %} ```python logging.getLogger(name=None) logging.getLogger(loggeyr_1) # Ex1. logging.getLogger(logger_1.logger_1_2) # Ex2. 可以使用`.` 代表 Logger 的階層。 ``` {% endcode %} {% hint style="success" %} **建議使用 `logger.getLogger(__name__)。`** 因為它將返回當前的 package 命名空間。如果有多個.py 檔案時很有用。 {% endhint %} ## Handler *** 如何處理 Logger 的資訊。 **將 Logger 輸出到 File。** {% code title="" %} ```python logging.FileHandler(filename, mode='a', encoding=NoHne, delay=False, errors=None) ``` {% endcode %} **將 Logger 輸出到 Terminal。** ```python logging.StreamHandler(stream=None) ``` **將 Logger 輸出到 Web 。** {% code title="PYTHON" %} ```python handlers.HTTPHandler(host, url, method='GET', secure=False, credentials=None, context=None) ``` {% endcode %} **設定 Handler 屬性。** 其他屬性詳見：[logging.Handler](https://docs.python.org/zh-tw/3/library/logging.html#logging.Handler) {% code title="PYTHON" %} ```python file_handler = logging.FileHandler('app.log') # ========================================================= # level file_handler.setLevel(logging.INFO) # Formatter formatter = logging.Formatter('%(asctime)s - %(levelname)s - %(message)s') file_handler.setFormatter(formatter) ``` {% endcode %} ## Filter *** Filter class 允許您自定義過濾器以根據特定條件有選擇地過濾掉日誌記錄。 它提供了一種微調日誌記錄系統中日誌記錄處理的方法。 Filter Filter class 是一個 base class， 它提供了一個 `filter(record)` 的方法，您需要在子 class 中覆蓋該方法。 `filter()` 方法將日誌記錄作為輸入，如果返回 True，則處理該日誌；則返回 True，如果返回 False，則跳過該日誌 。 {% hint style="success" %} **過濾器與日誌級別將會一起運行，日誌級別具有較高的優先度。** 例如：如果日誌級別設置為 WARNING，則只有 WARNING 或更高級別的日誌記錄才會被處理，而不管過濾器的設定。 {% endhint %} ## 範例 *** ### basicConfig {% code title="PYTHON" %} ```python '''basicConfig''' import logging # 建立 logger 和 FileHandler logging.basicConfig(filename = 'log.txt', level = logging.DEBUG, format = '{asctime}: {levelname}: {name}: {message}', style='{') #format = '%(asctime)s:%(levelname)s:%(name)s:%(message)s') logging.debug('Debug message') logging.info('Info message') logging.warning('Warning message') logging.error('Error message') logging.critical('Critical message') ``` {% endcode %} **執行結果：**
執行結果

執行結果

{% code title="PYTHON" %} ```python ''' basicConfig ->logger ->logger ''' import logging # 設定多個屬性 logging.basicConfig(filename='app.log', level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s') # ========================================================= # logger 1 logger = logging.getLogger('my_logger_1') logger.setLevel(logging.DEBUG) # log logger.debug('This is a debug message.') # ✔️✔️ logger.info('This is an informational message.') # ✔️✔️ logger.warning('This is a warning message.') # ✔️✔️ # ========================================================= # logger 2 logger_2 = logging.getLogger('my_logger_2') logger_2.setLevel(logging.WARNING) # log logger_2.debug('This is a debug message.') logger_2.info('This is an informational message.') logger_2.warning('This is a warning message.') # ✔️✔️ ``` {% endcode %} **執行結果:** {% code title="app.log" %} ``` 2023-07-19 18:18:20,495 - DEBUG - This is a debug message. 2023-07-19 18:18:20,495 - INFO - This is an informational message. 2023-07-19 18:18:20,495 - WARNING - This is a warning message. 2023-07-19 18:18:20,495 - WARNING - This is a warning message. ``` {% endcode %} ### fileConfig *** {% code title="INI" %} ```ini [loggers] keys=root [handlers] keys=fileHandler, consoleHandler [formatters] keys=defaultFormatter [logger_root] level=DEBUG handlers=fileHandler, consoleHandler [handler_fileHandler] # 輸出到 檔案 class=FileHandler level=DEBUG formatter=defaultFormatter args=('example.log', 'a') [handler_consoleHandler] # 輸出到 Terminal class=StreamHandler level=DEBUG formatter=defaultFormatter args=(sys.stdout,) [formatter_defaultFormatter] format=%(asctime)s - %(name)s - %(levelname)s - %(message)s datefmt=%Y-%m-%d %H:%M:%S ``` {% endcode %} {% code title="YAML" %} ```yaml version: 1 formatters: defaultFormatter: format: "%(asctime)s - %(name)s - %(levelname)s - %(message)s" datefmt: "%Y-%m-%d %H:%M:%S" handlers: fileHandler: # 輸出到 檔案 class: logging.FileHandler level: DEBUG formatter: defaultFormatter filename: app.log consoleHandler: # 輸出到 Terminal class: logging.StreamHandler level: DEBUG formatter: defaultFormatter stream: ext://sys.stdout loggers: root: level: DEBUG handlers: [fileHandler, consoleHandler] propagate: yes ``` {% endcode %} {% code title="PYTHON" %} ```python import yaml import logging import logging.config # 載入 configuration_file.conf，建立 logger logging.config.fileConfig('logging.conf') logger = logging.getLogger(__name__) # 寫入 Log logger.debug('This is a debug message') logger.info('This is an info message') logger.warning('This is a warning message') logger.error('This is an error message') # ========================================================= # 載入 configuration_file.yaml，建立 logger with open('logging.yaml', 'r') as f: config = yaml.safe_load(f.read()) logging.config.dictConfig(config) logger = logging.getLogger(__name__) # 寫入 Log logger.debug('This is a debug message') logger.info('This is an info message') logger.warning('This is a warning message') logger.error('This is an error message') ``` {% endcode %} ### logger *** {% code title="PYTHON" %} ```python '''getLogger('my_logger') ->FileHandler''' import logging # 建立 logger logger = logging.getLogger('my_logger') logger.setLevel(logging.DEBUG) # 建立 FileHandler file_handler = logging.FileHandler('app.log') formatter = logging.Formatter('%(asctime)s - %(levelname)s - %(message)s') file_handler.setLevel(logging.INFO) file_handler.setFormatter(formatter) # 加入 handler logger.addHandler(file_handler) # 寫入 log logger.info('This is an informational message.') logger.warning('This is a warning message.') ``` {% endcode %} **執行結果:** {% code title="app.log" %} ``` 2023-07-19 17:58:12,393 - INFO - This is an informational message. 2023-07-19 17:58:12,393 - WARNING - This is a warning message. ``` {% endcode %} {% code title="PYTHON" %} ```python '''getLogger(__name__) ->FileHandler''' import logging # 建立 logger logger = logging.getLogger(__name__) logger.setLevel(logging.DEBUG) formatter = logging.Formatter('%(name)s - %(asctime)s - %(levelname)s - %(message)s') # 建立 FileHandler file_handler = logging.FileHandler('app.log') file_handler.setLevel(logging.WARNING) file_handler.setFormatter(formatter) # 加入 handler logger.addHandler(file_handler) # log logger.debug('This is a debug message') logger.info('This is an info message') logger.warning('This is a warning message') logger.error('This is an error message') ``` {% endcode %} **執行結果:** {% code title="app.log" %} ``` __main__ - 2023-07-19 18:01:14,806 - WARNING - This is a warning message __main__ - 2023-07-19 18:01:14,806 - ERROR - This is an error message ``` {% endcode %} ### Handler *** {% code title="PYTHON" %} ```python import logging # 設定多個屬性 logger = logging.getLogger('my_logger') logger.setLevel(logging.DEBUG) formatter = logging.Formatter('%(asctime)s - %(levelname)s - %(message)s') # ========================================================= # 建立 FileHandler file_handler = logging.FileHandler('app.log') file_handler.setLevel(logging.INFO) file_handler.setFormatter(formatter) # ========================================================= # 建立 StreamHandler console_handler = logging.StreamHandler() console_handler.setLevel(logging.DEBUG) console_handler.setFormatter(formatter) # ========================================================= # 加入 handler logger.addHandler(file_handler) logger.addHandler(console_handler) # ========================================================= # 寫入 log logger.debug('This is a debug message.') logger.info('This is an informational message.') logger.warning('This is a warning message.') ``` {% endcode %} **執行結果:** ``` 2023-07-19 18:04:38,094 - DEBUG - This is a debug message. 2023-07-19 18:04:38,094 - INFO - This is an informational message. 2023-07-19 18:04:38,094 - WARNING - This is a warning message. ``` {% code title="app.log" %} ``` 2023-07-19 18:04:38,094 - INFO - This is an informational message. 2023-07-19 18:04:38,094 - WARNING - This is a warning message. ``` {% endcode %} ### Filter *** {% code title="PYTHON" %} ```python import logging class LoggerFilter(logging.Filter): def filter(self, record): return record.levelno >= logging.WARNING class HandlerFilter(logging.Filter): def filter(self, record): if record.msg.find('abc') == -1: return True return False # 建立 Handler logger = logging.getLogger('test') logger.setLevel(logging.INFO) # 建立 Handler stream_handler = logging.StreamHandler() logger.addHandler(stream_handler) # ========================================================= logger.warning('this is warning-1') # ✔️✔️ logger.info('this is info-1') # ✔️✔️ # ========================================================= logger.addFilter(LoggerFilter()) logger.warning('this is warning-2') # ✔️✔️ logger.info('this is info-2') # Skip this log # ========================================================= stream_handler.addFilter(HandlerFilter()) logger.warning('this is warning-3') # ✔️✔️ logger.info('this is info-3') # Skip this log logger.warning('this is warning-abc') # Skip this log ``` {% endcode %} **執行結果:** ``` this is warning-1 this is info-1 this is warning-2 this is warning-3 ``` ### Logger Decorator *** {% code title="PYTHON" %} ```python import logging def logger(func): def wrapper(*args, **kwargs): logging.info(f"Running \"{func.__name__}\" with arguments {args} and kwargs {kwargs}") result = func(*args, **kwargs) logging.info(f"{func.__name__} returned {result}") return result return wrapper logging.basicConfig(level=logging.INFO) @logger def adder(x, y): return x + y print(adder(10, 5)) ``` {% endcode %} **執行結果:** ``` INFO:root:Running "adder" with arguments (10, 5) and kwargs {} INFO:root:adder returned 15 15 ``` {% code title="PYTHON" %} ```python import logging class LevelFilter(logging.Filter): """ This is a custom filter class that filters out log messages below certain level. """ def filter(self, record): return record.levelno >= logging.INFO def setup_logger(): logger = logging.getLogger('custom_logger') logger.setLevel(logging.INFO) formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s') # Create console handler with a higher log level ch = logging.StreamHandler() ch.setLevel(logging.INFO) ch.setFormatter(formatter) logger.addHandler(ch) # Create file handler which logs even debug messages fh = logging.FileHandler('log_file.log') fh.setLevel(logging.INFO) fh.setFormatter(formatter) logger.addHandler(fh) # Add filter to the logger logger.addFilter(LevelFilter()) return logger logger = setup_logger() def logger_decorator(func): def wrapper(*args, **kwargs): logger.info(f"Running \"{func.__name__}\" with arguments {args} and kwargs {kwargs}") result = func(*args, **kwargs) logger.info(f"{func.__name__} returned {result}") return result return wrapper @logger_decorator def adder(x, y): return x + y print(adder(10, 5)) ``` {% endcode %} **執行結果:** ``` 2023-07-19 18:40:51,589 - custom_logger - INFO - Running "adder" with arguments (10, 5) and kwargs {} 2023-07-19 18:40:51,589 - custom_logger - INFO - adder returned 15 15 ``` ## 參考資料 *** **Python Doc** [基礎 Logging 指南 — Python 3.11.3 說明文件](https://docs.python.org/zh-tw/3/howto/logging.html#logging-basic-tutorial) [進階日誌教程 — Python 3.11.3 說明文件](https://docs.python.org/zh-tw/3/howto/logging.html#logging-advanced-tutorial) [日誌操作手冊 — Python 3.11.3 說明檔](https://docs.python.org/zh-tw/3/howto/logging-cookbook.html#logging-cookbook) [logging.basicConfig — Python 3.11.3 說明文件](https://docs.python.org/zh-tw/3/library/logging.html#logging.basicConfig) [logging.getLogger — Python 3.11.3 說明文件](https://docs.python.org/zh-tw/3/library/logging.html#logging.getLogger) [handlers — Python 3.11.3 文檔](https://docs.python.org/3/library/logging.handlers.html#module-logging.handlers) [config.fileConfig — Python 3.11.3 documentation](https://docs.python.org/3/library/logging.config.html#logging.config.fileConfig) [filter objects](https://docs.python.org/3/library/logging.html#filter-objects) **Blog** [Logging in Python - MachineLearningMastery.com](https://machinelearningmastery.com/logging-in-python/) [Logging in Python ——真正的 Python](https://realpython.com/python-logging/) [Python 日誌記錄基礎：方法教程、示例及更多 - Sematext](https://sematext.com/blog/python-logging/) [在 Python 中登錄 - MachineLearningMastery.com](https://machinelearningmastery.com/logging-in-python/) [如何使用logging.Filter？ | Python笔记](https://www.pynote.net/archives/2006) [Python logging 模組之 logging.basicConfig 用法和參數詳解\_Sir靜堂的博客-CSDN博客](https://blog.csdn.net/colinlee19860724/article/details/90965100) [Python - 日誌 (logging) 模組 | Titangene Blog](https://titangene.github.io/article/python-logging.html)