Comparing files once I have hostname

问题

I need a way to compare two files that have the same hostname in them. I have written a function that will parse out the hostnames and save that in a list. Once I have that I need to be able to compare the files.

Each file is in a different directory.

Step One: Retrieve "hostname" from each file. Step Two: Run compare on files with same "hostname" from two directories.

Retrieve hostname Code:

def hostname_parse(directory):
    results = []
    try:
        for filename in os.listdir(directory):
            if filename.endswith(('.cfg', '.startup', '.confg')):
                file_name = os.path.join(directory, filename)
                with open(file_name, "r") as in_file:
                    for line in in_file:
                        match = re.search('hostname\s(\S+)', line)
                        if match:
                            results.append(match.group(1))
                            #print "Match Found"
        return results
    except IOError as (errno, strerror):
        print "I/O error({0}): {1}".format(errno, strerror)
        print "Error in hostname_parse function"

Sample Data:

Test File:

19-30#
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname 19-30
!
boot-start-marker
boot-end-marker
!
ntp clock-period 17179738
ntp source Loopback0
!
end

19-30#

In this case the hostname is 19-30. For ease of testing I just used the same file but modified it to be the same or not the same.

As stated above. I can extract the hostname but am now looking for a way to then compare the files based on the hostname found.

At the core of things it is a file comparison. However being able to look at specific fields will be what I would like to accomplish. For starters I'm just looking to see that the files are identical. Case sensitivity shouldn't matter as these are cisco generated files that have the same formatting. The contents of the files are more important as I'm looking for "configuration" changes.

回答1:

Here is some code to meet your requirements. I had no way to test, so it may have a few challenges. Is used hash lib to calculate a hash on the file contents, as a way to find changes.

import hashlib
import os
import re

HOSTNAME_RE = re.compile(r'hostname +(\S+)')

def get_file_info_from_lines(filename, file_lines):
    hostname = None
    a_hash = hashlib.sha1()
    for line in file_lines:
        a_hash.update(line.encode('utf-8'))
        match = HOSTNAME_RE.match(line)
        if match:
            hostname = match.group(1)
    return hostname, filename, a_hash.hexdigest()

def get_file_info(filename):
    if filename.endswith(('.cfg', '.startup', '.confg')):
        with open(filename, "r") as in_file:
            return get_file_info_from_lines(filename, in_file.readlines())

def hostname_parse(directory):
    results = {}
    for filename in os.listdir(directory):
        info = get_file_info(filename)
        if info is not None:
            results[info[0]] = info
    return results

results1 = hostname_parse('dir1')
results2 = hostname_parse('dir2')

for hostname, filename, filehash in results1.values():
    if hostname in results2:
        _, filename2, filehash2 = results2[hostname]
        if filehash != filehash2:
            print("%s has a change (%s, %s)" % (
                hostname, filehash, filehash2))
            print(filename)
            print(filename2)
            print()

来源：https://stackoverflow.com/questions/41902759/comparing-files-once-i-have-hostname