python 日誌 logging模組詳細解析
Python中的logging模組可以讓你跟蹤程式碼執行時的事件,當程式崩潰時可以檢視日誌並且發現是什麼引發了錯誤。Log資訊有內建的層級——除錯(debugging)、資訊(informational)、警告(warnings)、錯誤(error)和嚴重錯誤(critical)。你也可以在logging中包含traceback資訊。不管是小專案還是大專案,都推薦在Python程式中使用logging。本文給大家介紹python 日誌 logging模組 介紹。
1 基本使用
配置logging基本的設定,然後在控制檯輸出日誌,
import logging logging.basicConfig(level = logging.INFO,format = '%(asctime)s - %(name)s - %(levelname)s - %(message)s') logger = logging.getLogger(__name__) logger.info("Start print log") logger.debug("Do something") logger.warning("Something maybe fail.") logger.info("Finish")
執行時,控制檯輸出,
2016-10-09 19:11:19,434 - __main__ - INFO - Start print log
2016-10-09 19:11:19,434 - __main__ - WARNING - Something maybe fail.
2016-10-09 19:11:19,434 - __main__ - INFO - Finish
logging中可以選擇很多訊息級別,如debug、info、warning、error以及critical。通過賦予logger或者handler不同的級別,開發者就可以只輸出錯誤資訊到特定的記錄檔案,或者在除錯時只記錄除錯資訊。
logging.basicConfig(level = logging.DEBUG,format = '%(asctime)s - %(name)s - %(levelname)s - %(message)s')
控制檯輸出,可以發現,輸出了debug的資訊。
2016-10-09 19:12:08,289 - __main__ - INFO - Start print log
2016-10-09 19:12:08,289 - __main__ - DEBUG - Do something
2016-10-09 19:12:08,289 - __main__ - WARNING - Something maybe fail.2016-10-09 19:12:08,289 - __main__ - INFO - Finish
logging.basicConfig函式各引數:
filename:指定日誌檔名;
filemode:和file函式意義相同,指定日誌檔案的開啟模式,'w'或者'a';
format:指定輸出的格式和內容,format可以輸出很多有用的資訊,
引數:作用
%(levelno)s:列印日誌級別的數值
%(levelname)s:列印日誌級別的名稱
%(pathname)s:列印當前執行程式的路徑,其實就是sys.argv[0]
%(filename)s:列印當前執行程式名
%(funcName)s:列印日誌的當前函式
%(lineno)d:列印日誌的當前行號
%(asctime)s:列印日誌的時間
%(thread)d:列印執行緒ID
%(threadName)s:列印執行緒名稱
%(process)d:列印程序ID
%(message)s:列印日誌資訊
datefmt:指定時間格式,同time.strftime();
level:設定日誌級別,預設為logging.WARNNING;
stream:指定將日誌的輸出流,可以指定輸出到sys.stderr,sys.stdout或者檔案,預設輸出到sys.stderr,當stream和filename同時指定時,stream被忽略;
2 將日誌寫入到檔案
2.2.1 將日誌寫入到檔案
設定logging,建立一個FileHandler,並對輸出訊息的格式進行設定,將其新增到logger,然後將日誌寫入到指定的檔案中,
import logging logger = logging.getLogger(__name__) logger.setLevel(level = logging.INFO) handler = logging.FileHandler("log.txt") handler.setLevel(logging.INFO) formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s') handler.setFormatter(formatter) logger.addHandler(handler) logger.info("Start print log") logger.debug("Do something") logger.warning("Something maybe fail.") logger.info("Finish")
log.txt中日誌資料為,
2016-10-09 19:01:13,263 - __main__ - INFO - Start print log
2016-10-09 19:01:13,263 - __main__ - WARNING - Something maybe fail.
2016-10-09 19:01:13,263 - __main__ - INFO - Finish
2.2 將日誌同時輸出到螢幕和日誌檔案
logger中新增StreamHandler,可以將日誌輸出到螢幕上,
import logging logger = logging.getLogger(__name__) logger.setLevel(level = logging.INFO) handler = logging.FileHandler("log.txt") handler.setLevel(logging.INFO) formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s') handler.setFormatter(formatter) console = logging.StreamHandler() console.setLevel(logging.INFO) logger.addHandler(handler) logger.addHandler(console) logger.info("Start print log") logger.debug("Do something") logger.warning("Something maybe fail.") logger.info("Finish")
可以在log.txt檔案和控制檯中看到,
2016-10-09 19:20:46,553 - __main__ - INFO - Start print log
2016-10-09 19:20:46,553 - __main__ - WARNING - Something maybe fail.
2016-10-09 19:20:46,553 - __main__ - INFO - Finish
可以發現,logging有一個日誌處理的主物件,其他處理方式都是通過addHandler新增進去,logging中包含的handler主要有如下幾種,
handler名稱:位置;作用
StreamHandler:logging.StreamHandler;日誌輸出到流,可以是sys.stderr,sys.stdout或者檔案
FileHandler:logging.FileHandler;日誌輸出到檔案
BaseRotatingHandler:logging.handlers.BaseRotatingHandler;基本的日誌回滾方式
RotatingHandler:logging.handlers.RotatingHandler;日誌回滾方式,支援日誌檔案最大數量和日誌檔案回滾
TimeRotatingHandler:logging.handlers.TimeRotatingHandler;日誌回滾方式,在一定時間區域內回滾日誌檔案
SocketHandler:logging.handlers.SocketHandler;遠端輸出日誌到TCP/IP sockets
DatagramHandler:logging.handlers.DatagramHandler;遠端輸出日誌到UDP sockets
SMTPHandler:logging.handlers.SMTPHandler;遠端輸出日誌到郵件地址
SysLogHandler:logging.handlers.SysLogHandler;日誌輸出到syslog
NTEventLogHandler:logging.handlers.NTEventLogHandler;遠端輸出日誌到Windows NT/2000/XP的事件日誌
MemoryHandler:logging.handlers.MemoryHandler;日誌輸出到記憶體中的指定buffer
HTTPHandler:logging.handlers.HTTPHandler;通過"GET"或者"POST"遠端輸出到HTTP伺服器
2.3 日誌回滾
使用RotatingFileHandler,可以實現日誌回滾,
import logging from logging.handlers import RotatingFileHandler logger = logging.getLogger(__name__) logger.setLevel(level = logging.INFO) #定義一個RotatingFileHandler,最多備份3個日誌檔案,每個日誌檔案最大1K rHandler = RotatingFileHandler("log.txt",maxBytes = 1*1024,backupCount = 3) rHandler.setLevel(logging.INFO) formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s') rHandler.setFormatter(formatter) console = logging.StreamHandler() console.setLevel(logging.INFO) console.setFormatter(formatter) logger.addHandler(rHandler) logger.addHandler(console) logger.info("Start print log") logger.debug("Do something") logger.warning("Something maybe fail.") logger.info("Finish")
可以在工程目錄中看到,備份的日誌檔案,
2016/10/09 19:36 732 log.txt
2016/10/09 19:36 967 log.txt.1
2016/10/09 19:36 985 log.txt.2
2016/10/09 19:36 976 log.txt.3
2.3 設定訊息的等級
可以設定不同的日誌等級,用於控制日誌的輸出,
日誌等級:使用範圍
FATAL:致命錯誤
CRITICAL:特別糟糕的事情,如記憶體耗盡、磁碟空間為空,一般很少使用
ERROR:發生錯誤時,如IO操作失敗或者連線問題
WARNING:發生很重要的事件,但是並不是錯誤時,如使用者登入密碼錯誤
INFO:處理請求或者狀態變化等日常事務
DEBUG:除錯過程中使用DEBUG等級,如演算法中每個迴圈的中間狀態
2.4 捕獲traceback
Python中的traceback模組被用於跟蹤異常返回資訊,可以在logging中記錄下traceback,
程式碼,
import logging logger = logging.getLogger(__name__) logger.setLevel(level = logging.INFO) handler = logging.FileHandler("log.txt") handler.setLevel(logging.INFO) formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s') handler.setFormatter(formatter) console = logging.StreamHandler() console.setLevel(logging.INFO) logger.addHandler(handler) logger.addHandler(console) logger.info("Start print log") logger.debug("Do something") logger.warning("Something maybe fail.") try: open("sklearn.txt","rb") except (SystemExit,KeyboardInterrupt): raise except Exception: logger.error("Faild to open sklearn.txt from logger.error",exc_info = True) logger.info("Finish")
控制檯和日誌檔案log.txt中輸出,
Start print log Something maybe fail. Faild to open sklearn.txt from logger.error Traceback (most recent call last): File "G:\zhb7627\Code\Eclipse WorkSpace\PythonTest\test.py",line 23,in <module> open("sklearn.txt","rb") IOError: [Errno 2] No such file or directory: 'sklearn.txt' Finish
也可以使用logger.exception(msg,_args),它等價於logger.error(msg,exc_info = True,_args),
將
logger.error("Faild to open sklearn.txt from logger.error",exc_info = True)
替換為,
logger.exception("Failed to open sklearn.txt from logger.exception")
控制檯和日誌檔案log.txt中輸出,
Start print log Something maybe fail. Failed to open sklearn.txt from logger.exception Traceback (most recent call last): File "G:\zhb7627\Code\Eclipse WorkSpace\PythonTest\test.py","rb") IOError: [Errno 2] No such file or directory: 'sklearn.txt' Finish
2.5 多模組使用logging
主模組mainModule.py,
import logging import subModule logger = logging.getLogger("mainModule") logger.setLevel(level = logging.INFO) handler = logging.FileHandler("log.txt") handler.setLevel(logging.INFO) formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s') handler.setFormatter(formatter) console = logging.StreamHandler() console.setLevel(logging.INFO) console.setFormatter(formatter) logger.addHandler(handler) logger.addHandler(console) logger.info("creating an instance of subModule.subModuleClass") a = subModule.SubModuleClass() logger.info("calling subModule.subModuleClass.doSomething") a.doSomething() logger.info("done with subModule.subModuleClass.doSomething") logger.info("calling subModule.some_function") subModule.som_function() logger.info("done with subModule.some_function")
子模組subModule.py,
import logging module_logger = logging.getLogger("mainModule.sub") class SubModuleClass(object): def __init__(self): self.logger = logging.getLogger("mainModule.sub.module") self.logger.info("creating an instance in SubModuleClass") def doSomething(self): self.logger.info("do something in SubModule") a = [] a.append(1) self.logger.debug("list a = " + str(a)) self.logger.info("finish something in SubModuleClass") def som_function(): module_logger.info("call function some_function")
執行之後,在控制和日誌檔案log.txt中輸出,
2016-10-09 20:25:42,276 - mainModule - INFO - creating an instance of subModule.subModuleClass
2016-10-09 20:25:42,279 - mainModule.sub.module - INFO - creating an instance in SubModuleClass
2016-10-09 20:25:42,279 - mainModule - INFO - calling subModule.subModuleClass.doSomething
2016-10-09 20:25:42,279 - mainModule.sub.module - INFO - do something in SubModule
2016-10-09 20:25:42,279 - mainModule.sub.module - INFO - finish something in SubModuleClass
2016-10-09 20:25:42,279 - mainModule - INFO - done with subModule.subModuleClass.doSomething
2016-10-09 20:25:42,279 - mainModule - INFO - calling subModule.some_function
2016-10-09 20:25:42,279 - mainModule.sub - INFO - call function some_function
2016-10-09 20:25:42,279 - mainModule - INFO - done with subModule.some_function
首先在主模組定義了logger'mainModule',並對它進行了配置,就可以在直譯器程序裡面的其他地方通過getLogger('mainModule')得到的物件都是一樣的,不需要重新配置,可以直接使用。定義的該logger的子logger,都可以共享父logger的定義和配置,所謂的父子logger是通過命名來識別,任意以'mainModule'開頭的logger都是它的子logger,例如'mainModule.sub'。
實際開發一個application,首先可以通過logging配置檔案編寫好這個application所對應的配置,可以生成一個根logger,如'PythonAPP',然後在主函式中通過fileConfig載入logging配置,接著在application的其他地方、不同的模組中,可以使用根logger的子logger,如'PythonAPP.Core','PythonAPP.Web'來進行log,而不需要反覆的定義和配置各個模組的logger。
3 通過JSON或者YAML檔案配置logging模組
儘管可以在Python程式碼中配置logging,但是這樣並不夠靈活,最好的方法是使用一個配置檔案來配置。在Python 2.7及以後的版本中,可以從字典中載入logging配置,也就意味著可以通過JSON或者YAML檔案載入日誌的配置。
3.1 通過JSON檔案配置
JSON配置檔案,
{ "version":1,"disable_existing_loggers":false,"formatters":{ "simple":{ "format":"%(asctime)s - %(name)s - %(levelname)s - %(message)s" } },"handlers":{ "console":{ "class":"logging.StreamHandler","level":"DEBUG","formatter":"simple","stream":"ext://sys.stdout" },"info_file_handler":{ "class":"logging.handlers.RotatingFileHandler","level":"INFO","filename":"info.log","maxBytes":"10485760","backupCount":20,"encoding":"utf8" },"error_file_handler":{ "class":"logging.handlers.RotatingFileHandler","level":"ERROR","filename":"errors.log","maxBytes":10485760,"encoding":"utf8" } },"loggers":{ "my_module":{ "level":"ERROR","handlers":["info_file_handler"],"propagate":"no" } },"root":{ "level":"INFO","handlers":["console","info_file_handler","error_file_handler"] } }
通過JSON載入配置檔案,然後通過logging.dictConfig配置logging,
import json import logging.config import os def setup_logging(default_path = "logging.json",default_level = logging.INFO,env_key = "LOG_CFG"): path = default_path value = os.getenv(env_key,None) if value: path = value if os.path.exists(path): with open(path,"r") as f: config = json.load(f) logging.config.dictConfig(config) else: logging.basicConfig(level = default_level) def func(): logging.info("start func") logging.info("exec func") logging.info("end func") if __name__ == "__main__": setup_logging(default_path = "logging.json") func()
3.2 通過YAML檔案配置
通過YAML檔案進行配置,比JSON看起來更加簡介明瞭,
version: 1 disable_existing_loggers: False formatters: simple: format: "%(asctime)s - %(name)s - %(levelname)s - %(message)s" handlers: console: class: logging.StreamHandler level: DEBUG formatter: simple stream: ext://sys.stdout info_file_handler: class: logging.handlers.RotatingFileHandler level: INFO formatter: simple filename: info.log maxBytes: 10485760 backupCount: 20 encoding: utf8 error_file_handler: class: logging.handlers.RotatingFileHandler level: ERROR formatter: simple filename: errors.log maxBytes: 10485760 backupCount: 20 encoding: utf8 loggers: my_module: level: ERROR handlers: [info_file_handler] propagate: no root: level: INFO handlers: [console,info_file_handler,error_file_handler]
通過YAML載入配置檔案,然後通過logging.dictConfig配置logging,
import yaml import logging.config import os def setup_logging(default_path = "logging.yaml","r") as f: config = yaml.load(f) logging.config.dictConfig(config) else: logging.basicConfig(level = default_level) def func(): logging.info("start func") logging.info("exec func") logging.info("end func") if __name__ == "__main__": setup_logging(default_path = "logging.yaml") func()
到此這篇關於python 日誌 logging模組 詳細解析的文章就介紹到這了,更多相關python logging模組內容請搜尋我們以前的文章或繼續瀏覽下面的相關文章希望大家以後多多支援我們!