builds/vpe-router/lib/charms/router.py

   1
   2 import paramiko
   3 import subprocess
   4
   5 from charmhelpers.core.hookenv import config
   6
   7
   8 class NetNS(object):
   9     def __init__(self, name):
  10         pass
  11
  12     @classmethod
  13     def create(cls, name):
  14         # @TODO: Need to check if namespace exists already
  15         try:
  16             ip('netns', 'add', name)
  17         except Exception as e:
  18             raise Exception('could not create net namespace: %s' % e)
  19
  20         return cls(name)
  21
  22     def up(self, iface, cidr):
  23         self.do('ip', 'link', 'set', 'dev', iface, 'up')
  24         self.do('ip', 'address', 'add', cidr, 'dev', iface)
  25
  26     def add_iface(self, iface):
  27         ip('link', 'set', 'dev', iface, 'netns', self.name)
  28
  29     def do(self, *cmd):
  30         ip(*['netns', 'exec', self.name] + cmd)
  31
  32
  33 def ip(*args):
  34     return _run(['ip'] + list(args))
  35
  36
  37 def _run(cmd, env=None):
  38     if isinstance(cmd, str):
  39         cmd = cmd.split() if ' ' in cmd else [cmd]
  40
  41     cfg = config()
  42     if all(k in cfg for k in ['pass', 'vpe-router', 'user']):
  43         router = cfg['vpe-router']
  44         user = cfg['user']
  45         passwd = cfg['pass']
  46
  47         if router and user and passwd:
  48             return ssh(cmd, router, user, passwd)
  49
  50     p = subprocess.Popen(cmd,
  51                          env=env,
  52                          stdout=subprocess.PIPE,
  53                          stderr=subprocess.PIPE)
  54     stdout, stderr = p.communicate()
  55     retcode = p.poll()
  56     if retcode > 0:
  57         raise subprocess.CalledProcessError(returncode=retcode,
  58                                             cmd=cmd,
  59                                             output=stderr.decode("utf-8").strip())
  60     return (''.join(stdout), ''.join(stderr))
  61
  62
  63 def ssh(cmd, host, user, password=None):
  64     ''' Suddenly this project needs to SSH to something. So we replicate what
  65         _run was doing with subprocess using the Paramiko library. This is
  66         temporary until this charm /is/ the VPE Router '''
  67
  68     cmds = ' '.join(cmd)
  69     client = paramiko.SSHClient()
  70     client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
  71     client.connect(host, port=22, username=user, password=password)
  72
  73     stdin, stdout, stderr = client.exec_command(cmds)
  74     retcode = stdout.channel.recv_exit_status()
  75     client.close()  # @TODO re-use connections
  76     if retcode > 0:
  77         output = stderr.read().strip()
  78         raise subprocess.CalledProcessError(returncode=retcode, cmd=cmd,
  79                                             output=output)
  80     return (''.join(stdout), ''.join(stderr))