docs/examples/generate_interfaces.py

   1 #!/usr/bin/python
   2
   3 import argparse
   4 import sys
   5 import subprocess
   6 import os
   7
   8 """ This script prints to stdout /etc/network/interfaces entries for
   9     requested interfaces.
  10
  11     Currently it supports generation of interfaces(5) section for all
  12     swp interfaces on the system. And also an interface section
  13     for a bridge with all swp ports.
  14
  15     Example use of this script:
  16
  17     generate the swp_defaults file:
  18     (bkup existing /etc/network/interfaces.d/swp_defaults file if one exists)
  19
  20     #generate_interfaces.py -s > /etc/network/interfaces.d/swp_defaults
  21
  22     User -m option if you want the new swp_defaults to be auto merged
  23     with the contents from the old file, use -m option
  24
  25     #generate_interfaces.py -s -m /etc/network/interfaces.d/swp_defaults > /etc/network/interfaces.d/swp_defaults.new
  26
  27     Include the swp_defaults file in /etc/network/interfaces file
  28     (if not already there) using the source command as shown below:
  29
  30     source /etc/network/interfaces.d/swp_defaults
  31
  32 """
  33
  34 def get_pci_interfaces():
  35     ports = []
  36     FNULL = open(os.devnull, 'w')
  37     try:
  38         cmd = '(ip -o link show | grep -v "@" | cut -d" " -f2 | sed \'s/:$//\')'
  39         output = subprocess.check_output(cmd, shell=True).split()
  40         for interface in output:
  41             cmd = 'udevadm info -a -p /sys/class/net/%s | grep \'SUBSYSTEMS=="pci"\'' % interface
  42             try:
  43                 subprocess.check_call(cmd, shell=True, stdout=FNULL)
  44                 ports.append(interface)
  45             except:
  46                 pass
  47     except:
  48         pass
  49     finally:
  50         FNULL.close()
  51     return ports
  52
  53 def get_swp_interfaces():
  54     porttab_path = '/var/lib/cumulus/porttab'
  55     ports = []
  56     try:
  57         with open(porttab_path, 'r') as f:
  58             for line in f.readlines():
  59                 line = line.strip()
  60                 if '#' in line:
  61                     continue
  62                 try:
  63                     ports.append(line.split()[0])
  64                 except ValueError:
  65                     continue
  66     except:
  67         try:
  68             ports = get_pci_interfaces()
  69         except Exception as e:
  70             print 'Error: Unsupported script: %s' % str(e)
  71             exit(1)
  72     if not ports:
  73         print 'Error: No ports found in %s' % porttab_path
  74         exit(1)
  75     return ports
  76
  77 def print_swp_defaults_header():
  78     print '''
  79 # ** This file is autogenerated by /usr/share/doc/ifupdown2/generate_interfaces.py **
  80 #
  81 # This is /etc/network/interfaces section for all available swp
  82 # ports on the system.
  83 #
  84 # To include this file in the main /etc/network/interfaces file,
  85 # copy this file under /etc/network/interfaces.d/ and use the
  86 # source line in the /etc/network/interfaces file.
  87 #
  88 # example entry in /etc/network/interfaces:
  89 #   source /etc/network/interfaces.d/<filename>
  90 #
  91 # See manpage interfaces(5) for details.
  92 '''
  93
  94 def print_bridge_untagged_defaults_header():
  95     print '''
  96 # ** This file is autogenerated by /usr/share/doc/ifupdown2/generate_interfaces.py **
  97 #
  98 # This is /etc/network/interfaces section for a bridge device with all swp
  99 # ports in the system.
 100 #
 101 # To include this file in the main /etc/network/interfaces file,
 102 # copy this file under /etc/network/interfaces.d/ and use the
 103 # source line in the /etc/network/interfaces file as shown below.
 104 # details.
 105 #
 106 # example entry in /etc/network/interfaces:
 107 #   source /etc/network/interfaces.d/filename
 108 #
 109 # See manpage interfaces(5) for details
 110 '''
 111
 112 def interfaces_print_swp_default(swp_intf):
 113     outbuf = None
 114     if args.mergefile:
 115         try:
 116             cmd = ['/sbin/ifquery', '%s' %swp_intf, '-i', '%s' %args.mergefile]
 117             outbuf = subprocess.check_output(cmd, stderr=subprocess.STDOUT)
 118         except Exception, e:
 119             # no interface found gen latest
 120             pass
 121     if not outbuf:
 122         outbuf = 'auto %s\niface %s\n\n' %(swp_intf, swp_intf)
 123     return outbuf
 124
 125 def interfaces_print_swp_defaults(swp_intfs):
 126     print_swp_defaults_header()
 127     outbuf = ''
 128     for i in swp_intfs:
 129         outbuf += interfaces_print_swp_default(i)
 130     print outbuf
 131
 132 def interfaces_print_bridge_default(swp_intfs):
 133     print_bridge_untagged_defaults_header()
 134     outbuf = 'auto bridge-untagged\n'
 135     outbuf += 'iface bridge-untagged\n'
 136     outbuf += '  bridge-ports \\\n'
 137     linen = 5
 138     ports = ''
 139     for i in range(0, len(swp_intfs), linen):
 140         if ports:
 141             ports += ' \\\n'
 142         ports += '      %s' %(' '.join(swp_intfs[i:i+linen]))
 143     outbuf += ports
 144     print outbuf
 145
 146 def populate_argparser(argparser):
 147     group = argparser.add_mutually_exclusive_group(required=False)
 148     group.add_argument('-s', '--swp-defaults', action='store_true',
 149                        dest='swpdefaults', help='generate swp defaults file')
 150     group.add_argument('-b', '--bridge-default', action='store_true',
 151                        dest='bridgedefault',
 152                        help='generate default untagged bridge')
 153     argparser.add_argument('-m', '--merge', dest='mergefile', help='merge ' +
 154                            'new generated iface content with the old one')
 155
 156 argparser =  argparse.ArgumentParser(description='ifupdown interfaces file gen helper')
 157 populate_argparser(argparser)
 158 args = argparser.parse_args(sys.argv[1:])
 159
 160 if not args.swpdefaults and not args.bridgedefault:
 161     argparser.print_help()
 162     exit(1)
 163
 164 if args.bridgedefault and args.mergefile:
 165     print 'error: mergefile option currently only supported with -s'
 166     argparser.print_help()
 167     exit(1)
 168
 169 swp_intfs = get_swp_interfaces()
 170
 171 if args.swpdefaults:
 172     interfaces_print_swp_defaults(swp_intfs)
 173 elif args.bridgedefault:
 174     interfaces_print_bridge_default(swp_intfs)
 175 else:
 176     argparser.print_help()