# # # Copyright (C) 2006, 2007 Google Inc. # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, but # WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA # 02110-1301, USA. """Module for the unix socket protocol This module implements the local unix socket protocl. You only need this module and the opcodes module in the client program in order to communicate with the master. The module is also be used by the master daemon. """ import socket import collections import time import errno from ganeti import serializer from ganeti import constants from ganeti import errors KEY_METHOD = 'method' KEY_ARGS = 'args' KEY_SUCCESS = "success" KEY_RESULT = "result" REQ_SUBMIT_JOB = "SubmitJob" REQ_WAIT_FOR_JOB_CHANGE = "WaitForJobChange" REQ_CANCEL_JOB = "CancelJob" REQ_ARCHIVE_JOB = "ArchiveJob" REQ_AUTOARCHIVE_JOBS = "AutoArchiveJobs" REQ_QUERY_JOBS = "QueryJobs" REQ_QUERY_INSTANCES = "QueryInstances" REQ_QUERY_NODES = "QueryNodes" REQ_QUERY_EXPORTS = "QueryExports" REQ_QUERY_CONFIG_VALUES = "QueryConfigValues" DEF_CTMO = 10 DEF_RWTO = 60 class ProtocolError(Exception): """Denotes an error in the server communication""" class ConnectionClosedError(ProtocolError): """Connection closed error""" class TimeoutError(ProtocolError): """Operation timeout error""" class EncodingError(ProtocolError): """Encoding failure on the sending side""" class DecodingError(ProtocolError): """Decoding failure on the receiving side""" class RequestError(ProtocolError): """Error on request This signifies an error in the request format or request handling, but not (e.g.) an error in starting up an instance. Some common conditions that can trigger this exception: - job submission failed because the job data was wrong - query failed because required fields were missing """ class NoMasterError(ProtocolError): """The master cannot be reached This means that the master daemon is not running or the socket has been removed. """ class Transport: """Low-level transport class. This is used on the client side. This could be replace by any other class that provides the same semantics to the Client. This means: - can send messages and receive messages - safe for multithreading """ def __init__(self, address, timeouts=None, eom=None): """Constructor for the Client class. Arguments: - address: a valid address the the used transport class - timeout: a list of timeouts, to be used on connect and read/write - eom: an identifier to be used as end-of-message which the upper-layer will guarantee that this identifier will not appear in any message There are two timeouts used since we might want to wait for a long time for a response, but the connect timeout should be lower. If not passed, we use a default of 10 and respectively 60 seconds. Note that on reading data, since the timeout applies to an invidual receive, it might be that the total duration is longer than timeout value passed (we make a hard limit at twice the read timeout). """ self.address = address if timeouts is None: self._ctimeout, self._rwtimeout = DEF_CTMO, DEF_RWTO else: self._ctimeout, self._rwtimeout = timeouts self.socket = None self._buffer = "" self._msgs = collections.deque() if eom is None: self.eom = '\3' else: self.eom = eom try: self.socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) self.socket.settimeout(self._ctimeout) try: self.socket.connect(address) except socket.timeout, err: raise TimeoutError("Connect timed out: %s" % str(err)) except socket.error, err: if err.args[0] in (errno.ENOENT, errno.ECONNREFUSED): raise NoMasterError((address,)) raise self.socket.settimeout(self._rwtimeout) except (socket.error, NoMasterError): if self.socket is not None: self.socket.close() self.socket = None raise def _CheckSocket(self): """Make sure we are connected. """ if self.socket is None: raise ProtocolError("Connection is closed") def Send(self, msg): """Send a message. This just sends a message and doesn't wait for the response. """ if self.eom in msg: raise EncodingError("Message terminator found in payload") self._CheckSocket() try: self.socket.sendall(msg + self.eom) except socket.timeout, err: raise TimeoutError("Sending timeout: %s" % str(err)) def Recv(self): """Try to receive a messae from the socket. In case we already have messages queued, we just return from the queue. Otherwise, we try to read data with a _rwtimeout network timeout, and making sure we don't go over 2x_rwtimeout as a global limit. """ self._CheckSocket() etime = time.time() + self._rwtimeout while not self._msgs: if time.time() > etime: raise TimeoutError("Extended receive timeout") try: data = self.socket.recv(4096) except socket.timeout, err: raise TimeoutError("Receive timeout: %s" % str(err)) if not data: raise ConnectionClosedError("Connection closed while reading") new_msgs = (self._buffer + data).split(self.eom) self._buffer = new_msgs.pop() self._msgs.extend(new_msgs) return self._msgs.popleft() def Call(self, msg): """Send a message and wait for the response. This is just a wrapper over Send and Recv. """ self.Send(msg) return self.Recv() def Close(self): """Close the socket""" if self.socket is not None: self.socket.close() self.socket = None class Client(object): """High-level client implementation. This uses a backing Transport-like class on top of which it implements data serialization/deserialization. """ def __init__(self, address=None, timeouts=None, transport=Transport): """Constructor for the Client class. Arguments: - address: a valid address the the used transport class - timeout: a list of timeouts, to be used on connect and read/write - transport: a Transport-like class If timeout is not passed, the default timeouts of the transport class are used. """ if address is None: address = constants.MASTER_SOCKET self.transport = transport(address, timeouts=timeouts) def CallMethod(self, method, args): """Send a generic request and return the response. """ # Build request request = { KEY_METHOD: method, KEY_ARGS: args, } # Send request and wait for response result = self.transport.Call(serializer.DumpJson(request, indent=False)) try: data = serializer.LoadJson(result) except Exception, err: raise ProtocolError("Error while deserializing response: %s" % str(err)) # Validate response if (not isinstance(data, dict) or KEY_SUCCESS not in data or KEY_RESULT not in data): raise DecodingError("Invalid response from server: %s" % str(data)) result = data[KEY_RESULT] if not data[KEY_SUCCESS]: # TODO: decide on a standard exception if (isinstance(result, (tuple, list)) and len(result) == 2 and isinstance(result[1], (tuple, list))): # custom ganeti errors err_class = errors.GetErrorClass(result[0]) if err_class is not None: raise err_class, tuple(result[1]) raise RequestError(result) return result def SubmitJob(self, ops): ops_state = map(lambda op: op.__getstate__(), ops) return self.CallMethod(REQ_SUBMIT_JOB, ops_state) def CancelJob(self, job_id): return self.CallMethod(REQ_CANCEL_JOB, job_id) def ArchiveJob(self, job_id): return self.CallMethod(REQ_ARCHIVE_JOB, job_id) def AutoArchiveJobs(self, age): return self.CallMethod(REQ_AUTOARCHIVE_JOBS, age) def WaitForJobChange(self, job_id, fields, prev_job_info, prev_log_serial): timeout = (DEF_RWTO - 1) / 2 while True: result = self.CallMethod(REQ_WAIT_FOR_JOB_CHANGE, (job_id, fields, prev_job_info, prev_log_serial, timeout)) if result != constants.JOB_NOTCHANGED: break return result def QueryJobs(self, job_ids, fields): return self.CallMethod(REQ_QUERY_JOBS, (job_ids, fields)) def QueryInstances(self, names, fields): return self.CallMethod(REQ_QUERY_INSTANCES, (names, fields)) def QueryNodes(self, names, fields): return self.CallMethod(REQ_QUERY_NODES, (names, fields)) def QueryExports(self, nodes): return self.CallMethod(REQ_QUERY_EXPORTS, nodes) def QueryConfigValues(self, fields): return self.CallMethod(REQ_QUERY_CONFIG_VALUES, fields) # TODO: class Server(object)