python中使用sys模板和logging模块获取行号和函数名的方法
1.python中没办法直接取得当前的行号和函数名。这是有人在论坛里提出的问题,底下一群人只是在猜测python为什么不像__file__一样提供__line__和__func__,但是却最终也没有找到解决方案。
2.如果一个函数在不知道自己名字的情况下,怎么才能递归调用自己。这是我一个同事问我的,其实也是获取函数名,但是当时也是回答不出来。
一切还要从我用python的logging模块说起,logging中的format中是有如下选项的:
参数说明
参数 | 说明 |
---|---|
%(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) |
%(lineno)d | Source line number where the logging call was issued (if available) |
%(funcName)s | Function name |
%(created)f | Time when the LogRecord was created (time.time() return value) |
%(asctime)s | Textual time when the LogRecord was created |
%(msecs)d | Millisecond portion of the creation time |
%(relativeCreated)d | Time in milliseconds when the LogRecord was created, relative to the time the logging module was loaded (typically at application startup time) |
%(thread)d | Thread ID (if available) |
%(threadName)s | Thread name (if available) |
%(process)d | Process ID (if available) |
%(message)s | The result of record.getMessage(), computed just as the record is emitted |
源码查看
也就是说,logging是能够获取到调用者的行号和函数名的,那会不会也可以获取到自己的行号和函数名呢?
我们来看一下源码,主要部分如下:
1 | import sys |
我简单解释一下,实际上是通过在currentframe函数中抛出一个异常,然后通过向上查找的方式,找到调用的信息。
其中
1 | rv = (co.co_filename, f.f_lineno, co.co_name) |
的三个值分别为文件名,行号,函数名。(可以去http://docs.python.org/library/sys.html来看一下代码中几个系统函数的说明)
动手尝试
OK,如果已经看懂了源码,那获取当前位置的行号和函数名相信也非常清楚了,代码如下:
1 | #!/usr/bin/python |
输入结果是:
1 | ('callfunc', 24) |
符合预期~~
哈哈,OK!现在应该不用再抱怨取不到行号和函数名了吧~
后来发现,其实也可以有更简单的方法,如下:
1 |
|
调用结果是:
1 | get_cur_info |