pwclient.py

from grpc.beta import implementations

import pwservice_pb2


TIMEOUT_SECONDS = 10


def run():
  channel = implementations.insecure_channel('localhost', 50051)
  stub = pwservice_pb2.beta_create_PasswordService_stub(channel)
  response = stub.ChangePassword(pwservice_pb2.ChangePasswordRequest(
      user='testuser', old_password='helloworld', new_password='newworld'),
      TIMEOUT_SECONDS)
  print "Password change response: ", response


if __name__ == '__main__':
  run()

pwserverd.py

import pamela as pam
import pwservice_pb2
import signal
import time


class PasswordServer(pwservice_pb2.BetaPasswordServiceServicer):

  def ChangePassword(self, request, context):
    try:
      pam.authenticate(request.user, request.old_password, 'login')
    except pam.PAMError, e:
      # TODO(bluecmd): Return some error code here
      return None
    # User is authenticated, change the password
    try:
      pam.change_password(request.user, request.old_password, 'login')
    except pam.PAMError, e:
      # TODO(bluecmd): Return some error code here
      return None
    return pwservice_pb2.EmptyReply()


def serve():
  server = pwservice_pb2.beta_create_PasswordService_server(
          PasswordServer())
  server.add_insecure_port('[::]:50051')
  server.start()
  try:
    while True:
      signal.pause()
  except KeyboardInterrupt:
    pass
  server.stop(0)

if __name__ == '__main__':
  serve()

pwservice.proto

syntax = "proto3";
package pwservice;

service PasswordService {
  rpc ChangePassword (ChangePasswordRequest) returns (EmptyReply) {}
}

message ChangePasswordRequest {
  string user = 1;
  string old_password = 2;
  string new_password = 3;
}

message EmptyReply {
}