Python:日誌模組logging的應用
通常,在商用軟體中均會有完整的日誌機制,之前使用C語言實現過一個《簡單的分級別寫日誌程式》,具有以下功能和不足:
在Python中,上面以實現的和已經實現的,均可以使用logging模組迅速搞定,且僅僅只需要一個配置檔案,兩行程式碼,實現過程如下(僅以輸出的磁碟檔案為例,命令輸出只需要修改配置檔案即可,具體可查API手冊):
1. 定義配置檔案logging.conf:
[loggers] keys=root,applog [handlers] keys=rotateFileHandler [formatters] keys=applog_format [formatter_applog_format] format=[%(asctime)s - %(name)s]%(levelname)s: %(message)s - %(filename)s:%(lineno)d [logger_root] level=NOTSET handlers=rotateFileHandler [logger_applog] level=NOTSET handlers=rotateFileHandler qualname=simple_example [handler_rotateFileHandler] class=handlers.RotatingFileHandler level=NOTSET formatter=applog_format args=('log_1.log', 'a', 10000, 9)
注意前三個[ ]中的keys,這個在後面各[ ]中定義定義,section的取名格式如looger_自定義名稱, handler_自定義名稱,我偷懶直接使用了標準名稱,其他一樣,最後一個要注意的就是format,即日誌檔案中內容的格式,具體見後面附一。level引數是日誌級別,可擴充套件,如果使用python自己的,有以下四個級別:
Level Numeric value CRITICAL 50 ERROR 40 WARNING 30 INFO 20 DEBUG 10 NOTSET 0
例如配置檔案中level定義為WARN,則INFO, DEBUG,NOTSET三個級別的日誌點則不會輸出,很方便的做到了日誌級別控制。
args定義了日誌方件名,寫方式,最大大小,儲存最多個數等屬性。
2.編碼,測試
#!/usr/bin/env python # -*- coding: utf-8 -*- import logging import logging.config #日誌初始化 LOG_FILENAME = 'logging.conf' logging.config.fileConfig(LOG_FILENAME) logger = logging.getLogger("simple_log_example") #測試程式碼 logger.debug("debug message") logger.info("info message") logger.warn("warn message") logger.error("error message") logger.critical("critical message")
執行後,檢視日誌檔案,內容如下:
[2012-02-11 14:47:05,483 - simple_log_example]DEBUG: debug message - test_log.py:48
[2012-02-11 14:47:05,483 - simple_log_example]INFO: info message - test_log.py:49
[2012-02-11 14:47:05,483 - simple_log_example]WARNING: warn message - test_log.py:50
[2012-02-11 14:47:05,483 - simple_log_example]ERROR: error message - test_log.py:51
[2012-02-11 14:47:05,483 - simple_log_example]CRITICAL: critical message - test_log.py:52
如將日誌級別設定為WARN,再次執行,檢視日誌:
[2012-02-11 14:54:20,046 - simple_log_example]WARNING: warn message - test_log.py:50
[2012-02-11 14:54:20,092 - simple_log_example]ERROR: error message - test_log.py:51
[2012-02-11 14:54:20,092 - simple_log_example]CRITICAL: critical message - test_log.py:52
附一:format引數格式說明:
Format Description
%(name)s Name of the logger (logging channel).
%(levelno)s Numeric logging level for the message (DEBUG, INFO, WARNING, ERROR, CRITICAL).
%(levelname)s Text logging level for the message ('DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL').
%(pathname)s Full pathname of the source file where the logging call was issued (if available).
%(filename)s Filename portion of pathname.
%(module)s Module (name portion of filename).
%(funcName)s Name of function containing the logging call.
%(lineno)d Source line number where the logging call was issued (if available).
%(created)f Time when the LogRecord was created (as returned by time.time()).
%(relativeCreated)d Time in milliseconds when the LogRecord was created, relative to the time the logging module was loaded.
%(asctime)s Human-readable time when the LogRecord was created. By default this is of the form “2003-07-08 16:49:45,896” (the numbers after the comma are millisecond portion of the time).
%(msecs)d Millisecond portion of the time when the LogRecord was created.
%(thread)d Thread ID (if available).
%(threadName)s Thread name (if available).
%(process)d Process ID (if available).
%(message)s The logged message, computed as msg % args.