support/split-logfile-ng.in

#!@pythonbin@
#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# split-logfile-ng -- Python port of the historical Perl split-logfile.
#
# This script will take a combined Web server access
# log file and break its contents into separate files.
# It assumes that the first field of each line is the
# virtual host identity (put there by "%v"), and that
# the logfiles should be named that+".log" in the current
# directory.
#
# The combined log file is read from stdin. Records read
# will be appended to any existing log files.

import re
import sys


def main():
    #
    # Operate on raw bytes, not decoded text, to match the Perl original
    # exactly: Perl reads STDIN as bytes, so its \s matches only ASCII
    # whitespace and lc() lowercases only ASCII A-Z.  Python's bytes
    # regexes are inherently ASCII-only and bytes.lower() lowercases only
    # ASCII, so reading sys.stdin.buffer reproduces Perl's behavior on
    # non-ASCII input (Unicode whitespace / case folding would otherwise
    # diverge).
    #
    log_file = {}

    for log_line in sys.stdin.buffer:
        #
        # Get the first token from the log record; it's the
        # identity of the virtual host to which the record
        # applies.
        #
        vhost = re.split(rb"\s", log_line, maxsplit=1)[0]
        #
        # Normalize the virtual host name to all lowercase.
        # If it's blank, the request was handled by the default
        # server, so supply a default name.  This shouldn't
        # happen, but caution rocks.
        #
        vhost = vhost.lower() or b"access"
        #
        # if the vhost contains a "/" or "\", it is illegal so just use
        # the default log to avoid any security issues due if it is interprted
        # as a directory separator.
        #
        if re.search(rb"[/\\]", vhost):
            vhost = b"access"
        #
        # If the log file for this virtual host isn't opened
        # yet, do it now.
        #
        if vhost not in log_file:
            try:
                log_file[vhost] = open(vhost + b".log", "ab")
            except IOError:
                sys.stderr.write("Can't open %s.log\n"
                                 % vhost.decode("latin-1"))
                sys.exit(1)
        #
        # Strip off the first token (which may be null in the
        # case of the default server), and write the edited
        # record to the current log file.
        #
        log_line = re.sub(rb"^\S*\s+", b"", log_line)
        log_file[vhost].write(log_line)

    for fh in log_file.values():
        fh.close()
    sys.exit(0)


if __name__ == "__main__":
    main()