charms/layers/sshproxy/reactive/sshproxy.py

   1 ##
   2 # Copyright 2016 Canonical Ltd.
   3 # All rights reserved.
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License"); you may
   6 # not use this file except in compliance with the License. You may obtain
   7 # a copy of the License at
   8 #
   9 #         http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 # Unless required by applicable law or agreed to in writing, software
  12 # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  13 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  14 # License for the specific language governing permissions and limitations
  15 # under the License.
  16 ##
  17
  18 from charmhelpers.core.hookenv import (
  19     action_fail,
  20     action_get,
  21     action_set,
  22     config,
  23 )
  24 from charms.reactive import (
  25     remove_state,
  26     set_state,
  27     when,
  28 )
  29 import charms.sshproxy
  30 import subprocess
  31
  32
  33 @when('config.changed')
  34 def ssh_configured():
  35     """ Checks to see if the charm is configured with SSH credentials. If so,
  36     set a state flag that can be used to execute ssh-only actions.
  37
  38     For example:
  39
  40     @when('sshproxy.configured')
  41     def run_remote_command(cmd):
  42         ...
  43
  44     @when_not('sshproxy.configured')
  45     def run_local_command(cmd):
  46         ...
  47     """
  48     cfg = config()
  49     if all(k in cfg for k in ['ssh-hostname', 'ssh-username',
  50                               'ssh-password', 'ssh-private-key']):
  51         set_state('sshproxy.configured')
  52     else:
  53         remove_state('sshproxy.configured')
  54
  55
  56 @when('actions.run')
  57 def run_command():
  58     """
  59     Run an arbitrary command, either locally or over SSH with the configured
  60     credentials.
  61     """
  62     try:
  63         cmd = action_get('command')
  64         output, err = charms.sshproxy._run(cmd)
  65         if len(err):
  66             action_fail("Command '{}' returned error code {}".format(cmd, err))
  67         else:
  68             action_set({'output': output})
  69     except subprocess.CalledProcessError as e:
  70         action_fail('Command failed: %s (%s)' %
  71                     (' '.join(e.cmd), str(e.output)))
  72     finally:
  73         remove_state('actions.run')