python/google/appengine/client/services/port_manager.py

   1 #!/usr/bin/env python
   2 #
   3 # Copyright 2007 Google Inc.
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License");
   6 # you may not use this file except in compliance with the License.
   7 # You may obtain 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,
  13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14 # See the License for the specific language governing permissions and
  15 # limitations under the License.
  16 #
  17 """A helper file with a helper class for opening ports."""
  18
  19 import logging
  20
  21 from google.appengine.client.services import vme_errors
  22
  23 # These ports are used by our code or critical system daemons.
  24 RESERVED_HOST_PORTS = [22,  # SSH
  25                        5000,  # Docker registry
  26                        8080,  # HTTP server
  27                        10000,  # For unlocking?
  28                        10001,  # Nanny stubby proxy endpoint
  29                       ]
  30 # We allow users to forward traffic to our HTTP server internally.
  31 RESERVED_DOCKER_PORTS = [22,  # SSH
  32                          5000,  # Docker registry
  33                          10001,  # Nanny stubby proxy endpoint
  34                         ]
  35
  36
  37 class InconsistentPortConfigurationError(vme_errors.PermanentAppError):
  38   """The port is already in use."""
  39   pass
  40
  41
  42 class IllegalPortConfigurationError(vme_errors.PermanentAppError):
  43   """Raised if the port configuration is illegal."""
  44   pass
  45
  46
  47 def CreatePortManager(forwarded_ports):
  48   """Construct a PortManager object with port forwarding configured.
  49
  50   Args:
  51     forwarded_ports: A dictionary containing desired mappings from VM host port
  52         to docker container port.
  53
  54   Returns:
  55     The PortManager instance.
  56   """
  57   port_manager_obj = PortManager()
  58   ports_list = forwarded_ports if forwarded_ports else []
  59   logging.debug('setting forwarded ports %s', ports_list)
  60   port_manager_obj.Add(ports_list, 'forwarded')
  61   return port_manager_obj
  62
  63
  64 class PortManager(object):
  65   """A helper class for VmManager to deal with port mappings."""
  66
  67   def __init__(self):
  68     self.used_host_ports = {}
  69     self.port_mappings = {}
  70
  71   def Add(self, ports, kind):
  72     """Load port configurations and adds them to an internal dict.
  73
  74     Args:
  75       ports: A list of strings or a CSV representing port forwarding.
  76       kind: what kind of port configuration this is, only used for error
  77         reporting.
  78
  79     Raises:
  80       InconsistentPortConfigurationError: If a port is configured to do
  81         two different conflicting things.
  82       IllegalPortConfigurationError: If the port is out of range or
  83         is not a number.
  84
  85     Returns:
  86       A dictionary with forwarding rules as external_port => local_port.
  87     """
  88     if isinstance(ports, basestring):
  89       # split a csv
  90       ports = [port.strip() for port in ports.split(',')]
  91     port_translations = {}
  92     for port in ports:
  93       try:
  94         if ':' in port:
  95           host_port, docker_port = (int(p.strip()) for p in port.split(':'))
  96           port_translations[host_port] = docker_port
  97         else:
  98           host_port = int(port)
  99           docker_port = host_port
 100           port_translations[host_port] = host_port
 101         if (host_port in self.used_host_ports and
 102             self.used_host_ports[host_port] != docker_port):
 103           raise InconsistentPortConfigurationError(
 104               'Configuration conflict, port %d configured to forward '
 105               'differently.' % host_port)
 106         self.used_host_ports[host_port] = docker_port
 107         if (host_port < 1 or host_port > 65535 or
 108             docker_port < 1 or docker_port > 65535):
 109           raise IllegalPortConfigurationError(
 110               'Failed to load %s port configuration: invalid port %s'
 111               % (kind, port))
 112         if docker_port < 1024:
 113           raise IllegalPortConfigurationError(
 114               'Cannot listen on port %d as it is priviliged, use a forwarding '
 115               'port.' % docker_port)
 116         if docker_port in RESERVED_DOCKER_PORTS:
 117           raise IllegalPortConfigurationError(
 118               'Cannot use port %d as it is reserved on the VM.'
 119               % docker_port)
 120         if host_port in RESERVED_HOST_PORTS:
 121           raise IllegalPortConfigurationError(
 122               'Cannot use port %d as it is reserved on the VM.'
 123               % host_port)
 124       except ValueError as e:
 125         logging.exception('Bad port description')
 126         raise IllegalPortConfigurationError(
 127             'Failed to load %s port configuration: "%s" error: "%s"'
 128             % (kind, port, e))
 129     # At this point we know they are not destructive.
 130     self.port_mappings.update(port_translations)
 131     return port_translations
 132
 133   def GetAllMappedPorts(self):
 134     """Returns all mapped ports.
 135
 136     Returns:
 137       A dict of port mappings {host: docker}
 138     """
 139     return self.port_mappings