Question

我使用python打开大型日志文件，如

Thu Oct  4 23:14:40 2012 [pid 16901] CONNECT: Client "66.249.74.228"
Thu Oct  4 23:14:40 2012 [pid 16900] [ftp] OK LOGIN: Client "66.249.74.228", anon     password "googlebot@google.com"
Thu Oct  4 23:17:42 2012 [pid 16902] [ftp] FAIL DOWNLOAD: Client "66.249.74.228",   "/pub/10.5524/100001_101000/100039/Assembly-2011/Pa9a_assembly_config4.scafSeq.gz",  14811136 bytes, 79.99Kbyte/sec
Fri Oct  5 00:04:13 2012 [pid 25809] CONNECT: Client "66.249.74.228"
Fri Oct  5 00:04:14 2012 [pid 25808] [ftp] OK LOGIN: Client "66.249.74.228", anon password "googlebot@google.com"
Fri Oct  5 00:07:16 2012 [pid 25810] [ftp] FAIL DOWNLOAD: Client "66.249.74.228", "/pub/10.5524/100001_101000/100027/Raw_data/PHOlcpDABDWABPE/090715_I80_FC427DJAAXX_L8_PHOlcpDABDWABPE_1.fq.gz", 14811136 bytes, 79.99Kbyte/sec
Fri Oct  5 00:13:19 2012 [pid 27354] CONNECT: Client "1.202.186.53"
Fri Oct  5 00:13:19 2012 [pid 27353] [ftp] OK LOGIN: Client "1.202.186.53", anon password "mozilla@example.com"

我想从tail命令读取文件末尾的行以获取最近7天记录。

这是我的代码，如何更改它。

import time
f= open("/opt/CLiMB/Storage1/log/vsftp.log")
def OnlyRecent(line):
   if  time.strptime(line.split("[")[0].strip(),"%a %b %d %H:%M:%S %Y")>     time.gmtime(time.time()-(60*60*24*7)): 
    return True
return False
filename= time.strftime('%Y%m%d')+'.log'
f1= open(filename,'w')
for line in f:
 if OnlyRecent(line):
        print line
        f1.write(line)
f.close()
f1.close()

Answer 1

使用file.seek()跳转到文件末尾的某个偏移量。例如，要打印文件的最后1Kb而不读取文件的开头，请执行以下操作：

with open("/opt/CLiMB/Storage1/log/vsftp.log") as f:
     f.seek(-1000, os.SEEK_END)
     print f.read()

Answer 2

我没有检查过这个，只是重新格式化代码：

从时间模块中导入较少的详细信息
dropwhile而不是for .. if
with上下文打开/关闭文件
PEP8
miscs

-

from time import time, gmtime, strptime
from itertools import dropwhile

deadline = gmtime(time()-(60*60*24*7))
formatting = "%a %b %d %H:%M:%S %Y"

def not_recent(line):
    return strptime(line.split("[")[0].strip(), formatting) <= deadline

with open("/opt/CLiMB/Storage1/log/vsftp.log") as f:
    filename = time.strftime('%Y%m%d')+'.log'
    with open(filename,'w') as f1:
        for line in dropwhile(not_recent, f):
            print line
            f1.write(line)

Answer 3

另一个实现，考虑到你正在处理庞大的日志文件

def tail(fname, n):
    fin = os.open(fname,os.O_RDONLY ) #Get an open file desc
    size = os.fstat(fin).st_size #Get the size from the stat
    fin = os.fdopen(fin) #Convert fd to file obj
    count = 0
    fin.seek(size) #Seek to the end of the file
    try:
        while count < n: #Loop until the count of newlines exceed the tail size
            pos = fin.tell() - 2 #Step backward
            if pos == -1: #Until you are past the begining
                raise StopIteration #When you end the Loop
            fin.seek(pos)
            if fin.read(1) == '\n': #And check if the next character is a new line
                count += 1 #Maintaining the count
    except StopIteration:
        pass

    return fin

用法

for e in tail("Test.log",10):
    print e

python打开大日志文件

3 个答案: