LinuxQuimper

Ceci est une ancienne révision du document !

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Nous utiliserons squid qui permet de réecrire certaines url (celles correspondant aux dépots) grace à un script python.

Exemple :
- on demande http://archive.ubuntu.com/ubuntu/pool/a/alien_1.2.3.deb
- Squid transmet l'url au script python
- le script retranscris en adresse locale : http://127.0.0.1/ubuntu/pool/a/alien_1.2.3.deb
- Si le fichier local existe, le script renvoi l'url locale, sinon renvoi l'url non modifiée

Voici le script en question /usr/local/bin/squid-redirector.py :

#!/usr/bin/env python

#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
#
#    Author : Fanch317 (fanch@linuxquimper.org)
#
#    Date : 2009-09-27
#    Version 0.6
#
#    Description : Ce script est un redirecteur pour squid.
#                  Il est destinne a faire passer toute requete de depots de
#                  distributions vers des depots locaux plus rapides lors
#                  d'install-party. (Proxy transparent)

import sys,re,os.path,urllib2,logging,random

levels = (logging.DEBUG, logging.INFO, logging.WARNING, logging.ERROR, logging.CRITICAL)
LOGLEVEL = logging.INFO

# Definition des deots locaux
redirectors = {}
redirectors[0] = ["(.*\.)?archive.ubuntu.com/ubuntu", "http://127.0.0.1/ubuntu/"]
redirectors[1] = ["(.*\.)?archlinux.fr/extra","http://127.0.0.1/archlinux/extra/extra/"]
redirectors[2] = ["(.*\.)?archlinux.fr/core","http://127.0.0.1/archlinux/core/core/"]
redirectors[3] = ["(.*\.)?slitaz.org/packages","http://127.0.0.1/slitaz/"]
redirectors[4] = ["(.*\.)?slitaz.org/pxe","http://127.0.0.1/slitaz/pxe"]
redirectors[5] = ["(.*\.)?slitaz.org/boot","http://127.0.0.1/slitaz/boot"]
redirectors[6] = ["(.*\.)?archive.debian.org/debian","http://127.0.0.1/debian/"]

# Definition du chemin du fichier log et de sa verbosite
LOG_FILENAME = '/var/log/squid/squid-redirector.log'




logging.basicConfig(filename=LOG_FILENAME,level=LOGLEVEL,format='%(asctime)s %(levelname)s %(message)s',datefmt='%d/%m/%Y %H:%M:%S')


logging.info('---------------------------------------')
logging.info('Lancement d\'thread squid-redirector.py')
logging.info('---------------------------------------')



while True:
  # URL ip-address/fqdn ident method
  line_squid = sys.stdin.readline().strip()
  
  logging.debug('Reception d\'une requete : '+line_squid)
  
  # Recuperation de l'URL
  try:
    list = line_squid.split(' ')
    url_input = list[0]
    
    # Recuperation de l'origine du client
    try:
      client_input = list[1] + rnd
    except:
      logging.warning('Impossible de recuperer l\'origine du client depuis la chaine '+line_squid)
      client_input = "NC"
    logging.info(client_input + ' Reception d\'une URL par : ' + url_input)

    i = 0
    while i < len(redirectors):
      logging.debug(client_input + ' Test sur le depot %d' %(i))

      try:
        # On test sur le depot correpond a ce genre d'URL
        if re.search('http://' + redirectors[i][0],url_input):
          logging.debug(client_input + ' L\'url correspond au depot')
          try:
            url_locale = re.sub(r'http://' + redirectors[i][0],redirectors[i][1],url_input)
            logging.debug(client_input + ' Verification de la presence du fichier local : ' + url_locale)
            urllib2.urlopen(url_locale)
            url_output = url_locale + '\n'
            logging.info(client_input + ' Ce fichier est en cache : ' + url_output)
            print url_output
            break
          except:
            # Le fichier est introuvable sur le depot
            logging.debug(client_input + ' Cette URL n\'est telechargeable dans ce depot')
      except:
        # L'URL ne correspond pas au depot
        logging.debug(client_input + ' Ce depot ne correspond pas a l\'URL')
      i = i + 1
    
    # Tout les depots ont ete testes, aucun ne correspond
    logging.info(client_input + ' Aucun depot ne contient cette URL')
    print url_input #+ '\n'
      
  except:
    logging.error(client_input + ' Impossible de recuperer l\'URL depuis la chaine '+line_squid)
    
  sys.stdout.flush()