Simran Basi | 7498d20 | 2012-07-10 15:21:28 -0700 | [diff] [blame^] | 1 | # Copyright (c) 2012 The Chromium OS Authors. All rights reserved. |
| 2 | # Use of this source code is governed by a BSD-style license that can be |
| 3 | # found in the LICENSE file. |
| 4 | |
| 5 | import atexit |
| 6 | import errno |
| 7 | import logging |
| 8 | import re |
| 9 | import socket |
| 10 | import threading |
| 11 | import time |
| 12 | import xmlrpclib |
| 13 | |
| 14 | from config import rpm_config |
| 15 | from MultiThreadedXMLRPCServer import MultiThreadedXMLRPCServer |
| 16 | import rpm_controller |
| 17 | from rpm_infrastructure_exception import RPMInfrastructureException |
| 18 | import rpm_logging_config |
| 19 | |
| 20 | LOG_FILENAME_FORMAT = rpm_config.get('GENERAL','dispatcher_logname_format') |
| 21 | |
| 22 | |
| 23 | class RPMDispatcher(object): |
| 24 | """ |
| 25 | This class is the RPM dispatcher server and it is responsible for |
| 26 | communicating directly to the RPM devices to change a DUT's outlet status. |
| 27 | |
| 28 | When an RPMDispatcher is initialized it registers itself with the frontend |
| 29 | server, who will field out outlet requests to this dispatcher. |
| 30 | |
| 31 | Once a request is received the dispatcher looks up the RPMController |
| 32 | instance for the given DUT and then queues up the request and blocks until |
| 33 | it is processed. |
| 34 | |
| 35 | @var _address: IP address or Hostname of this dispatcher server. |
| 36 | @var _frontend_server: URI of the frontend server. |
| 37 | @var _lock: Lock used to synchronize access to _worker_dict. |
| 38 | @var _port: Port assigned to this server instance. |
| 39 | @var _worker_dict: Dictionary mapping RPM hostname's to RPMController |
| 40 | instances. |
| 41 | """ |
| 42 | |
| 43 | |
| 44 | def __init__(self, address, port): |
| 45 | """ |
| 46 | RPMDispatcher constructor. |
| 47 | |
| 48 | Initialized instance vars and registers this server with the frontend |
| 49 | server. |
| 50 | |
| 51 | @param address: Address of this dispatcher server. |
| 52 | @param port: Port assigned to this dispatcher server. |
| 53 | |
| 54 | @raise RPMInfrastructureException: Raised if the dispatch server is |
| 55 | unable to register with the frontend |
| 56 | server. |
| 57 | """ |
| 58 | self._address = address |
| 59 | self._port = port |
| 60 | self._lock = threading.Lock() |
| 61 | self._worker_dict = {} |
| 62 | self._frontend_server = rpm_config.get('RPM_INFRASTRUCTURE', |
| 63 | 'frontend_uri') |
| 64 | logging.info('Registering this rpm dispatcher with the frontend ' |
| 65 | 'server at %s.', self._frontend_server) |
| 66 | client = xmlrpclib.ServerProxy(self._frontend_server) |
| 67 | # De-register with the frontend when the dispatcher exit's. |
| 68 | atexit.register(self._unregister) |
| 69 | try: |
| 70 | client.register_dispatcher(self._get_serveruri()) |
| 71 | except socket.error as er: |
| 72 | err_msg = ('Unable to register with frontend server. Error: %s.' % |
| 73 | errno.errorcode[er.errno]) |
| 74 | logging.error(err_msg) |
| 75 | raise RPMInfrastructureException(err_msg) |
| 76 | |
| 77 | |
| 78 | def _worker_dict_put(self, key, value): |
| 79 | """ |
| 80 | Private method used to synchronize access to _worker_dict. |
| 81 | |
| 82 | @param key: key value we are using to access _worker_dict. |
| 83 | @param value: value we are putting into _worker_dict. |
| 84 | """ |
| 85 | with self._lock: |
| 86 | self._worker_dict[key] = value |
| 87 | |
| 88 | |
| 89 | def _worker_dict_get(self, key): |
| 90 | """ |
| 91 | Private method used to synchronize access to _worker_dict. |
| 92 | |
| 93 | @param key: key value we are using to access _worker_dict. |
| 94 | @return: value found when accessing _worker_dict |
| 95 | """ |
| 96 | with self._lock: |
| 97 | return self._worker_dict.get(key) |
| 98 | |
| 99 | |
| 100 | def is_up(self): |
| 101 | """ |
| 102 | Allows the frontend server to see if the dispatcher server is up before |
| 103 | attempting to queue requests. |
| 104 | |
| 105 | @return: True. If connection fails, the client proxy will throw a socket |
| 106 | error on the client side. |
| 107 | """ |
| 108 | return True |
| 109 | |
| 110 | |
| 111 | def queue_request(self, dut_hostname, new_state): |
| 112 | """ |
| 113 | Looks up the appropriate RPMController instance for this DUT and queues |
| 114 | up the request. |
| 115 | |
| 116 | @param dut_hostname: hostname of the DUT whose outlet we are trying to |
| 117 | change. |
| 118 | @param new_state: [ON, OFF, CYCLE] state we want to the change the |
| 119 | outlet to. |
| 120 | @return: True if the attempt to change power state was successful, |
| 121 | False otherwise. |
| 122 | """ |
| 123 | logging.info('Received request to set DUT: %s to state: %s', |
| 124 | dut_hostname, new_state) |
| 125 | rpm_controller = self._get_rpm_controller(dut_hostname) |
| 126 | return rpm_controller.queue_request(dut_hostname, new_state) |
| 127 | |
| 128 | |
| 129 | def _get_rpm_controller(self, dut_hostname): |
| 130 | """ |
| 131 | Private method that retreives the appropriate RPMController instance for |
| 132 | this DUT or calls _create_rpm_controller it if it does not already |
| 133 | exist. |
| 134 | |
| 135 | @param dut_hostname: hostname of the DUT whose RPMController we want. |
| 136 | |
| 137 | @return: RPMController instance responsible for this DUT's RPM. |
| 138 | """ |
| 139 | rpm_hostname = re.sub('host[^.]*', 'rpm1', dut_hostname, count=1) |
| 140 | logging.info('RPM hostname for DUT %s is %s', dut_hostname, |
| 141 | rpm_hostname) |
| 142 | rpm_controller = self._worker_dict_get(rpm_hostname) |
| 143 | if not rpm_controller: |
| 144 | rpm_controller = self._create_rpm_controller(rpm_hostname) |
| 145 | self._worker_dict_put(rpm_hostname, rpm_controller) |
| 146 | return rpm_controller |
| 147 | |
| 148 | |
| 149 | def _create_rpm_controller(self, rpm_hostname): |
| 150 | """ |
| 151 | Determines the type of RPMController required and initializes it. |
| 152 | |
| 153 | @param rpm_hostname: Hostname of the RPM we need to communicate with. |
| 154 | |
| 155 | @return: RPMController instance responsible for this RPM. |
| 156 | """ |
| 157 | hostname_elements = rpm_hostname.split('-') |
| 158 | rack_id = hostname_elements[-2] |
| 159 | rpm_typechecker = re.compile('rack[0-9]+[a-z]+') |
| 160 | if rpm_typechecker.match(rack_id): |
| 161 | logging.info('RPM is a webpowered device') |
| 162 | return rpm_controller.WebPoweredRPMController(rpm_hostname) |
| 163 | else: |
| 164 | logging.info('RPM is a Sentry CDU device') |
| 165 | return rpm_controller.SentryRPMController(rpm_hostname) |
| 166 | |
| 167 | |
| 168 | def _get_serveruri(self): |
| 169 | """ |
| 170 | Formats the _address and _port into a meaningful URI string. |
| 171 | |
| 172 | @return: URI of this dispatch server. |
| 173 | """ |
| 174 | return 'http://%s:%d' % (self._address, self._port) |
| 175 | |
| 176 | |
| 177 | def _unregister(self): |
| 178 | """ |
| 179 | Tells the frontend server that this dispatch server is shutting down and |
| 180 | to unregister it. |
| 181 | |
| 182 | Called by atexit. |
| 183 | |
| 184 | @raise RPMInfrastructureException: Raised if the dispatch server is |
| 185 | unable to unregister with the |
| 186 | frontend server. |
| 187 | """ |
| 188 | logging.info('Dispatch server shutting down. Unregistering with RPM ' |
| 189 | 'frontend server.') |
| 190 | client = xmlrpclib.ServerProxy(self._frontend_server) |
| 191 | try: |
| 192 | client.unregister_dispatcher(self._get_serveruri()) |
| 193 | except socket.error as er: |
| 194 | err_msg = ('Unable to unregister with frontend server. Error: %s.' % |
| 195 | errno.errorcode[er.errno]) |
| 196 | logging.error(err_msg) |
| 197 | raise RPMInfrastructureException(err_msg) |
| 198 | |
| 199 | |
| 200 | def launch_server_on_unused_port(): |
| 201 | """ |
| 202 | Looks up an unused port on this host and launches the xmlrpc server. |
| 203 | |
| 204 | Useful for testing by running multiple dispatch servers on the same host. |
| 205 | |
| 206 | @return: server,port - server object and the port that which it is listening |
| 207 | to. |
| 208 | """ |
| 209 | address = socket.gethostbyname(socket.gethostname()) |
| 210 | sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) |
| 211 | # Set this socket to allow reuse. |
| 212 | sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) |
| 213 | sock.bind(('', 0)) |
| 214 | port = sock.getsockname()[1] |
| 215 | server = MultiThreadedXMLRPCServer((address, port), |
| 216 | allow_none=True) |
| 217 | sock.close() |
| 218 | return server, port |
| 219 | |
| 220 | |
| 221 | if __name__ == '__main__': |
| 222 | """ |
| 223 | Main function used to launch the dispatch server. Creates an instance of |
| 224 | RPMDispatcher and registers it to a MultiThreadedXMLRPCServer instance. |
| 225 | """ |
| 226 | rpm_logging_config.set_up_logging(LOG_FILENAME_FORMAT) |
| 227 | # Get the local ip _address and set the server to utilize it. |
| 228 | address = socket.gethostbyname(socket.gethostname()) |
| 229 | server, port = launch_server_on_unused_port() |
| 230 | rpm_dispatcher = RPMDispatcher(address, port) |
| 231 | server.register_instance(rpm_dispatcher) |
| 232 | server.serve_forever() |