root / lib / luxi.py @ 8d8d650c
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# Copyright (C) 2006, 2007 Google Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301, USA.
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"""Module for the unix socket protocol
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This module implements the local unix socket protocol. You only need
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this module and the opcodes module in the client program in order to
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communicate with the master.
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The module is also used by the master daemon.
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"""
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import socket |
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import collections |
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import time |
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import errno |
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import logging |
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from ganeti import serializer |
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from ganeti import constants |
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from ganeti import errors |
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KEY_METHOD = "method"
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KEY_ARGS = "args"
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KEY_SUCCESS = "success"
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KEY_RESULT = "result"
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REQ_SUBMIT_JOB = "SubmitJob"
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REQ_SUBMIT_MANY_JOBS = "SubmitManyJobs"
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REQ_WAIT_FOR_JOB_CHANGE = "WaitForJobChange"
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REQ_CANCEL_JOB = "CancelJob"
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REQ_ARCHIVE_JOB = "ArchiveJob"
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REQ_AUTOARCHIVE_JOBS = "AutoArchiveJobs"
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REQ_QUERY_JOBS = "QueryJobs"
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REQ_QUERY_INSTANCES = "QueryInstances"
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REQ_QUERY_NODES = "QueryNodes"
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REQ_QUERY_EXPORTS = "QueryExports"
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REQ_QUERY_CONFIG_VALUES = "QueryConfigValues"
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REQ_QUERY_CLUSTER_INFO = "QueryClusterInfo"
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REQ_QUERY_TAGS = "QueryTags"
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REQ_QUEUE_SET_DRAIN_FLAG = "SetDrainFlag"
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REQ_SET_WATCHER_PAUSE = "SetWatcherPause"
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DEF_CTMO = 10
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DEF_RWTO = 60
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class ProtocolError(errors.GenericError): |
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"""Denotes an error in the LUXI protocol"""
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class ConnectionClosedError(ProtocolError): |
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"""Connection closed error"""
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class TimeoutError(ProtocolError): |
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"""Operation timeout error"""
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class RequestError(ProtocolError): |
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"""Error on request
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This signifies an error in the request format or request handling,
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but not (e.g.) an error in starting up an instance.
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Some common conditions that can trigger this exception:
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- job submission failed because the job data was wrong
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- query failed because required fields were missing
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"""
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class NoMasterError(ProtocolError): |
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"""The master cannot be reached
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This means that the master daemon is not running or the socket has
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been removed.
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"""
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class Transport: |
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"""Low-level transport class.
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This is used on the client side.
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This could be replace by any other class that provides the same
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semantics to the Client. This means:
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- can send messages and receive messages
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- safe for multithreading
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"""
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def __init__(self, address, timeouts=None, eom=None): |
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"""Constructor for the Client class.
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Arguments:
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- address: a valid address the the used transport class
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- timeout: a list of timeouts, to be used on connect and read/write
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- eom: an identifier to be used as end-of-message which the
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upper-layer will guarantee that this identifier will not appear
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in any message
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There are two timeouts used since we might want to wait for a long
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time for a response, but the connect timeout should be lower.
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If not passed, we use a default of 10 and respectively 60 seconds.
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Note that on reading data, since the timeout applies to an
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invidual receive, it might be that the total duration is longer
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than timeout value passed (we make a hard limit at twice the read
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timeout).
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"""
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self.address = address
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if timeouts is None: |
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self._ctimeout, self._rwtimeout = DEF_CTMO, DEF_RWTO |
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else:
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self._ctimeout, self._rwtimeout = timeouts |
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self.socket = None |
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self._buffer = "" |
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self._msgs = collections.deque()
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if eom is None: |
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self.eom = '\3' |
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else:
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self.eom = eom
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try:
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self.socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
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self.socket.settimeout(self._ctimeout) |
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try:
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self.socket.connect(address)
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except socket.timeout, err:
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raise TimeoutError("Connect timed out: %s" % str(err)) |
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except socket.error, err:
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if err.args[0] in (errno.ENOENT, errno.ECONNREFUSED): |
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raise NoMasterError(address)
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raise
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self.socket.settimeout(self._rwtimeout) |
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except (socket.error, NoMasterError):
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if self.socket is not None: |
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self.socket.close()
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self.socket = None |
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raise
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def _CheckSocket(self): |
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"""Make sure we are connected.
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"""
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if self.socket is None: |
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raise ProtocolError("Connection is closed") |
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def Send(self, msg): |
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"""Send a message.
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This just sends a message and doesn't wait for the response.
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"""
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if self.eom in msg: |
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raise ProtocolError("Message terminator found in payload") |
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self._CheckSocket()
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try:
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# TODO: sendall is not guaranteed to send everything
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self.socket.sendall(msg + self.eom) |
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except socket.timeout, err:
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raise TimeoutError("Sending timeout: %s" % str(err)) |
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def Recv(self): |
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"""Try to receive a message from the socket.
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In case we already have messages queued, we just return from the
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queue. Otherwise, we try to read data with a _rwtimeout network
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timeout, and making sure we don't go over 2x_rwtimeout as a global
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limit.
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"""
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self._CheckSocket()
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etime = time.time() + self._rwtimeout
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while not self._msgs: |
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if time.time() > etime:
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raise TimeoutError("Extended receive timeout") |
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while True: |
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try:
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data = self.socket.recv(4096) |
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except socket.error, err:
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if err.args and err.args[0] == errno.EAGAIN: |
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continue
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raise
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except socket.timeout, err:
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raise TimeoutError("Receive timeout: %s" % str(err)) |
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break
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if not data: |
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raise ConnectionClosedError("Connection closed while reading") |
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new_msgs = (self._buffer + data).split(self.eom) |
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self._buffer = new_msgs.pop()
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self._msgs.extend(new_msgs)
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return self._msgs.popleft() |
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def Call(self, msg): |
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"""Send a message and wait for the response.
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This is just a wrapper over Send and Recv.
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"""
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self.Send(msg)
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return self.Recv() |
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def Close(self): |
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"""Close the socket"""
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if self.socket is not None: |
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self.socket.close()
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self.socket = None |
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def ParseRequest(msg): |
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"""Parses a LUXI request message.
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"""
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try:
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request = serializer.LoadJson(msg) |
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except ValueError, err: |
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raise ProtocolError("Invalid LUXI request (parsing error): %s" % err) |
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logging.debug("LUXI request: %s", request)
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if not isinstance(request, dict): |
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logging.error("LUXI request not a dict: %r", msg)
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raise ProtocolError("Invalid LUXI request (not a dict)") |
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method = request.get(KEY_METHOD, None)
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args = request.get(KEY_ARGS, None)
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if method is None or args is None: |
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logging.error("LUXI request missing method or arguments: %r", msg)
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raise ProtocolError(("Invalid LUXI request (no method or arguments" |
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" in request): %r") % msg)
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return (method, args)
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def ParseResponse(msg): |
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"""Parses a LUXI response message.
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"""
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# Parse the result
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try:
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data = serializer.LoadJson(msg) |
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except Exception, err: |
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raise ProtocolError("Error while deserializing response: %s" % str(err)) |
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# Validate response
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if not (isinstance(data, dict) and |
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KEY_SUCCESS in data and |
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KEY_RESULT in data):
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raise ProtocolError("Invalid response from server: %r" % data) |
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return (data[KEY_SUCCESS], data[KEY_RESULT])
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def FormatResponse(success, result): |
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"""Formats a LUXI response message.
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"""
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response = { |
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KEY_SUCCESS: success, |
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KEY_RESULT: result, |
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} |
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logging.debug("LUXI response: %s", response)
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return serializer.DumpJson(response)
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def FormatRequest(method, args): |
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"""Formats a LUXI request message.
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"""
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# Build request
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request = { |
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KEY_METHOD: method, |
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KEY_ARGS: args, |
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} |
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# Serialize the request
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return serializer.DumpJson(request, indent=False) |
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def CallLuxiMethod(transport_cb, method, args): |
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"""Send a LUXI request via a transport and return the response.
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"""
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assert callable(transport_cb) |
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request_msg = FormatRequest(method, args) |
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# Send request and wait for response
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response_msg = transport_cb(request_msg) |
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(success, result) = ParseResponse(response_msg) |
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if success:
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return result
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errors.MaybeRaise(result) |
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raise RequestError(result)
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class Client(object): |
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"""High-level client implementation.
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This uses a backing Transport-like class on top of which it
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implements data serialization/deserialization.
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"""
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def __init__(self, address=None, timeouts=None, transport=Transport): |
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"""Constructor for the Client class.
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Arguments:
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- address: a valid address the the used transport class
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- timeout: a list of timeouts, to be used on connect and read/write
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- transport: a Transport-like class
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If timeout is not passed, the default timeouts of the transport
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class are used.
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"""
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if address is None: |
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address = constants.MASTER_SOCKET |
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self.address = address
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self.timeouts = timeouts
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self.transport_class = transport
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self.transport = None |
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self._InitTransport()
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def _InitTransport(self): |
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"""(Re)initialize the transport if needed.
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"""
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if self.transport is None: |
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self.transport = self.transport_class(self.address, |
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timeouts=self.timeouts)
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def _CloseTransport(self): |
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"""Close the transport, ignoring errors.
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"""
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if self.transport is None: |
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return
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try:
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old_transp = self.transport
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self.transport = None |
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old_transp.Close() |
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except Exception: # pylint: disable-msg=W0703 |
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pass
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def _SendMethodCall(self, data): |
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# Send request and wait for response
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try:
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self._InitTransport()
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return self.transport.Call(data) |
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except Exception: |
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self._CloseTransport()
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raise
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def CallMethod(self, method, args): |
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"""Send a generic request and return the response.
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"""
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return CallLuxiMethod(self._SendMethodCall, method, args) |
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def SetQueueDrainFlag(self, drain_flag): |
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return self.CallMethod(REQ_QUEUE_SET_DRAIN_FLAG, drain_flag) |
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def SetWatcherPause(self, until): |
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return self.CallMethod(REQ_SET_WATCHER_PAUSE, [until]) |
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def SubmitJob(self, ops): |
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ops_state = map(lambda op: op.__getstate__(), ops) |
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return self.CallMethod(REQ_SUBMIT_JOB, ops_state) |
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def SubmitManyJobs(self, jobs): |
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jobs_state = [] |
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for ops in jobs: |
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jobs_state.append([op.__getstate__() for op in ops]) |
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return self.CallMethod(REQ_SUBMIT_MANY_JOBS, jobs_state) |
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def CancelJob(self, job_id): |
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return self.CallMethod(REQ_CANCEL_JOB, job_id) |
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def ArchiveJob(self, job_id): |
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return self.CallMethod(REQ_ARCHIVE_JOB, job_id) |
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def AutoArchiveJobs(self, age): |
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timeout = (DEF_RWTO - 1) / 2 |
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return self.CallMethod(REQ_AUTOARCHIVE_JOBS, (age, timeout)) |
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def WaitForJobChange(self, job_id, fields, prev_job_info, prev_log_serial): |
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timeout = (DEF_RWTO - 1) / 2 |
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while True: |
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result = self.CallMethod(REQ_WAIT_FOR_JOB_CHANGE,
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(job_id, fields, prev_job_info, |
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prev_log_serial, timeout)) |
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if result != constants.JOB_NOTCHANGED:
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break
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return result
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def QueryJobs(self, job_ids, fields): |
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return self.CallMethod(REQ_QUERY_JOBS, (job_ids, fields)) |
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def QueryInstances(self, names, fields, use_locking): |
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return self.CallMethod(REQ_QUERY_INSTANCES, (names, fields, use_locking)) |
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def QueryNodes(self, names, fields, use_locking): |
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return self.CallMethod(REQ_QUERY_NODES, (names, fields, use_locking)) |
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def QueryExports(self, nodes, use_locking): |
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return self.CallMethod(REQ_QUERY_EXPORTS, (nodes, use_locking)) |
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def QueryClusterInfo(self): |
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return self.CallMethod(REQ_QUERY_CLUSTER_INFO, ()) |
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def QueryConfigValues(self, fields): |
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return self.CallMethod(REQ_QUERY_CONFIG_VALUES, fields) |
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def QueryTags(self, kind, name): |
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return self.CallMethod(REQ_QUERY_TAGS, (kind, name)) |
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# TODO: class Server(object)
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