charms/layers/vyos-proxy/reactive/vyos_proxy.py

   1
   2 import subprocess
   3 import paramiko
   4
   5 from charmhelpers.core.hookenv import (
   6     config,
   7     status_set,
   8     action_get,
   9     action_set,
  10     action_fail,
  11 )
  12
  13 from charms.reactive import (
  14     when,
  15     when_not,
  16     set_state as set_flag,
  17     remove_state as remove_flag,
  18 )
  19
  20
  21 @when('config.changed')
  22 def test_connection():
  23     status_set('maintenance', 'configuring ssh connection')
  24     remove_flag('vyos-proxy.ready')
  25     try:
  26         who, _ = run('whoami')
  27     except MgmtNotConfigured as e:
  28         remove_flag('vyos-proxy.configured')
  29         status_set('blocked', str(e))
  30     except subprocess.CalledProcessError as e:
  31         remove_flag('vyos-proxy.configured')
  32         status_set('blocked', e.output)
  33     else:
  34         set_flag('vyos-proxy.configured')
  35
  36
  37 @when('vyos-proxy.configured')
  38 @when_not('vyos-proxy.ready')
  39 def vyos_proxy_ready():
  40     status_set('active', 'ready')
  41     set_flag('vyos-proxy.ready')
  42
  43
  44 @when('actions.ping')
  45 @when_not('vyos-proxy.configured')
  46 def pingme():
  47     action_fail('proxy is not ready')
  48
  49
  50 @when('actions.ping')
  51 @when('vyos-proxy.configured')
  52 def pingme_forreal():
  53     try:
  54         result, err = run('ping -qc {} {}'.format(action_get('count'), action_get('destination')))
  55     except:
  56         action_fail('ping command failed')
  57     finally:
  58         remove_flag('actions.ping')
  59
  60     # Here you can send results back from ping, if you had time to parse it
  61     action_set({'output': result})
  62
  63
  64
  65 class MgmtNotConfigured(Exception):
  66     pass
  67
  68
  69 def run(cmd):
  70     ''' Suddenly this project needs to SSH to something. So we replicate what
  71         _run was doing with subprocess using the Paramiko library. This is
  72         temporary until this charm /is/ the VPE Router '''
  73
  74     cfg = config()
  75
  76     hostname = cfg.get('hostname')
  77     password = cfg.get('pass')
  78     username = cfg.get('user')
  79
  80     if not (username and password and hostname):
  81         raise MgmtNotConfigured('incomplete remote credentials')
  82
  83     client = paramiko.SSHClient()
  84     client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
  85
  86     try:
  87         client.connect(cfg.get('hostname'), port=22,
  88                        username=cfg.get('user'), password=cfg.get('pass'))
  89     except paramiko.ssh_exception.AuthenticationException:
  90         raise MgmtNotConfigured('invalid credentials')
  91
  92     stdin, stdout, stderr = client.exec_command(cmd)
  93     retcode = stdout.channel.recv_exit_status()
  94     client.close()  # @TODO re-use connections
  95     if retcode > 0:
  96         output = stderr.read().strip()
  97         raise subprocess.CalledProcessError(returncode=retcode, cmd=cmd,
  98                                             output=output)
  99     return (''.join(stdout), ''.join(stderr))