#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
This script is a replacement for split-logfile and rotatelogs from the
Apache webserver distribution suited as a pipe log consumer. It has a
file handle pool like vlogger.

Copyright (c) 2008 Jan Dittberner <jan@dittberner.info>
Version: $Id$
"""
import os
import sys
import time

FHPOOL = {}
FHPOOLSIZE = 100


def getfromfhpool(key, dirname, filename):
    """Get a file handle from the filehandle pool.

    The function checks whether a filehandle for the given key is in
    the pool and returns it. If there is no such handle the pool size
    is checked and when it would be exceeded an LRU algorithm is used
    to remove the oldest handle from the cache. When removing the item
    from the cache the file is closed. After the pool size check the
    file identified by dirname and filename is opened for appending
    log date..
    """
    now = time.time()
    if key in FHPOOL:
        FHPOOL[key][0] = now
        return FHPOOL[key][1]
    if len(FHPOOL) == FHPOOLSIZE:
        mintime = now
        minkey = None
        for (ckey, value) in FHPOOL.iteritems():
            if value[0] <= mintime:
                mintime = value[0]
                minkey = ckey
        FHPOOL[minkey][1].close()
        del FHPOOL[minkey]
    FHPOOL[key] = [now, open(os.path.join(dirname, filename), "a")]
    return FHPOOL[key][1]


def main(basedir, logfilename, inputdata):
    """
    This function controls the input parsing process.

    It reads one log line at a time and adds it to the appropriate log
    file.
    """
    while 1:
        line = inputdata.readline()
        if line.find(" ") == -1:
            continue
        (vhost, logentry) = line.split(" ", 1)
        if vhost and logentry:
            logdir = os.path.join(basedir, vhost)
            if not os.path.isdir(logdir):
                os.makedirs(logdir)
            fhandle = getfromfhpool(vhost, logdir, logfilename)
            fhandle.write(logentry)
            fhandle.flush()


def usage():
    """Usage: %s <logbasedir> <logfilename>

    Logs incoming lines in a format starting with a vhost field to
    <logbasedir>/<vhost>/<logfilename>. Directories below <logbasedir>
    are created automatically.
    """
    print usage.__doc__ % (sys.argv[0])


if __name__ == '__main__':
    if len(sys.argv) < 3:
        usage()
        sys.exit(1)
    main(sys.argv[1], sys.argv[2], sys.stdin)