python3实现tailf命令的示例代码
由于Windows上面没有类似linux上面的tailf命令,所以下面的python脚本来代替其能力。
taijavascriptlf.py
import re import time import os import argparse def follow(thefile): thefile.seek(0, os.SEEK_END) while True: _line = thefile.readline() if not _line: time.sleep(0.1) python continue yield _line class Pipe(object): def handle(self, _line): pass class AwkPipe(Pipe): def __init__(self, fs, script): self.fs = fs self.script = script def handle(self, _line: str): clos = _line.split(self.fs) try: return self.script.format(*clos) except IndexError as e: return "parse_err:" + self.script + str(clos) class GrepPipe(Pipe): def __init__(self, grep_str): self.grep_str = grep_str def handle(self, _line): if re.search(grep, _line): return _line return None class PrintPipe(Pipe): def handle(self, _line): if _line.endswith("\n"): print(_line, end="") else: print(_line) if __name__ == '__main__': arg_parser = argparse.ArgumentParser() arg_parser.add_argument("file") arg_parser.add_argument("-F", help="分隔符", required=False) arg_parser.add_argument("-s", help="脚本,使用format的{0}格式,{0}标识分割后的第一个元素占位,依次递增。", required=False) arg_parser.add_argument("-g", "--grep", help="过滤字符,支持正则", required=False) args = arg_parser.parse_args() logfile = open(args.file, "r", encoding='utf-8') grep = args.grep pipes = [] if args.F and args.s: pipes.append(AwkPipe(args.F, args.s)) if grep: pipythonpes.append(GrepPipe(grep)) pipes.append(PrintPipe()) try: loglines = follow(logfile) for line in loglines: _tmp_line = line.strip() if not _tmp_line: continue for pipe in pipes: _tmp_line = pipe.handle(_tmp_line) if _tmp_line is None: http://www.devze.com break except KeyboardInterrupt: pass
例子:
输出内容:python3 tailf.py app.log
按照分隔符分割并按照指定格式输出:python3 tailf.py app.log -F "|" -s "第一列:{0} 第二列:{1}"
输出匹配内容:python3 tailf.py app.log -g 匹配字符
按照分隔符分割并按照指定格式的匹配内容输出:python3 tailf.py app.log -F "|" -s "第一列:{0} 第二列:{1}" -g 匹配字符
补:python实现tail -f命令功能
#!/usr/bin/env python #!encoding:utf-8 ''' Python-Tail - Unix tail follow implementation in Python. python-tail can be used to monitor changes to a file. 编程客栈 Example: import tail # Create a tail instance t = tail.Tail('file-to-be-followed') # Register a callback function to be called when a new line is found in the followed file. # If no callback function is registerd, new lines would be printed to standard out. t.register_callback(callback_function) # Follow the file with 5 seconds as sleep time between iterations. # If sleep time is not provided 1 second is used as the default time. t.follow(s=5) ''' # Author - Kasun Herath <kasunh01 at gmail.com> # Source - https://github.com/kasun/python-tail import os import sys import time class Tail(object): ''' Represents a tail command. ''' def __init__(self, tailed_file): ''' Initiate a Tail instance. Check for file validity, assigns callback function to standard out. Arguments: tailed_file - File to be followed. ''' self.check_file_validity(tailed_file) self.tailed_file = tailed_file self.callback = sys.stdout.write def follow(self, s=1): ''' Do a tail follow. If a callback function is registered it is called with every new line. Else printed to standard out. Arguments: s - Number of seconds to wait between each iteration; Defaults to 1. ''' with open(self.tailed_file) as file_: # Go to the end of file file_.seek(0,2) while True: curr_position = file_.tell() line = file_.readline() if not line: file_.seek(curr_position) else: self.callback(line) time.sleep(s) def register_callback(self, func): ''' Overrides default callback function to provided function. ''' self.callback = func def check_file_validity(self, file_): ''' Check whether the a given file exists, readable and is a file ''' if not os.Access(file_, os.F_OK): raise TailError("File '%s' does not exist" % (file_)) if not os.access(file_, os.R_OK): raise TailError("File '%s' not readable" % (file_)) if os.path.isdir(file_): raise TailError("File '%s' is a directory" % (file_)) class TailError(Exception): def __init__(self, msg): self.message = msg def __str__(self): return self.message if __name__=='__main__': args = sys.argv if len(args)<2: print 'need one filename parameter' exit(1) t = Tail(args[1]) #t.register_callback(print_line) t.follow()
到此这篇关于python3实现tailf命令的示例代码的文章就介绍到这了,更多相关python3 tailf命令内容请搜索编程客栈(www.devze.com)以前的文章或继续浏览下面的相关文章希望大家以后多多支持编程客栈(www.devze.com)!
精彩评论