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#
#
# 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 protocol. You only need
this module and the opcodes module in the client program in order to
communicate with the master.
The module is also used by the master daemon.
"""
import socket
import collections
import time
from ganeti import serializer
KEY_METHOD = "method"
KEY_ARGS = "args"
KEY_SUCCESS = "success"
KEY_RESULT = "result"
REQ_SUBMIT_MANY_JOBS = "SubmitManyJobs"
REQ_WAIT_FOR_JOB_CHANGE = "WaitForJobChange"
REQ_CANCEL_JOB = "CancelJob"
REQ_ARCHIVE_JOB = "ArchiveJob"
REQ_QUERY_INSTANCES = "QueryInstances"
REQ_QUERY_CONFIG_VALUES = "QueryConfigValues"
REQ_QUERY_CLUSTER_INFO = "QueryClusterInfo"
REQ_QUEUE_SET_DRAIN_FLAG = "SetDrainFlag"
REQ_SET_WATCHER_PAUSE = "SetWatcherPause"
DEF_CTMO = 10
DEF_RWTO = 60
class ProtocolError(errors.GenericError):
"""Denotes an error in the LUXI protocol"""
class ConnectionClosedError(ProtocolError):
"""Connection closed error"""
class TimeoutError(ProtocolError):
"""Operation timeout error"""
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.
"""
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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)
utils.Retry(self._Connect, 1.0, self._ctimeout,
args=(self.socket, address, self._ctimeout))
except utils.RetryTimeout:
raise TimeoutError("Connect timed out")
self.socket.settimeout(self._rwtimeout)
except (socket.error, NoMasterError):
if self.socket is not None:
self.socket.close()
self.socket = None
raise
@staticmethod
def _Connect(sock, address, timeout):
sock.settimeout(timeout)
try:
sock.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)
if err.args[0] == errno.EAGAIN:
# Server's socket backlog is full at the moment
raise utils.RetryAgain()
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 ProtocolError("Message terminator found in payload")
self._CheckSocket()
try:
# TODO: sendall is not guaranteed to send everything
self.socket.sendall(msg + self.eom)
except socket.timeout, err:
raise TimeoutError("Sending timeout: %s" % str(err))
def Recv(self):
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")
while True:
try:
data = self.socket.recv(4096)
except socket.error, err:
if err.args and err.args[0] == errno.EAGAIN:
continue
raise
except socket.timeout, err:
raise TimeoutError("Receive timeout: %s" % str(err))
break
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
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def ParseRequest(msg):
"""Parses a LUXI request message.
"""
try:
request = serializer.LoadJson(msg)
except ValueError, err:
raise ProtocolError("Invalid LUXI request (parsing error): %s" % err)
logging.debug("LUXI request: %s", request)
if not isinstance(request, dict):
logging.error("LUXI request not a dict: %r", msg)
raise ProtocolError("Invalid LUXI request (not a dict)")
method = request.get(KEY_METHOD, None)
args = request.get(KEY_ARGS, None)
if method is None or args is None:
logging.error("LUXI request missing method or arguments: %r", msg)
raise ProtocolError(("Invalid LUXI request (no method or arguments"
" in request): %r") % msg)
return (method, args)
def ParseResponse(msg):
"""Parses a LUXI response message.
"""
# Parse the result
try:
data = serializer.LoadJson(msg)
except Exception, err:
raise ProtocolError("Error while deserializing response: %s" % str(err))
# Validate response
if not (isinstance(data, dict) and
KEY_SUCCESS in data and
KEY_RESULT in data):
raise ProtocolError("Invalid response from server: %r" % data)
return (data[KEY_SUCCESS], data[KEY_RESULT])
def FormatResponse(success, result):
"""Formats a LUXI response message.
"""
response = {
KEY_SUCCESS: success,
KEY_RESULT: result,
}
logging.debug("LUXI response: %s", response)
return serializer.DumpJson(response)
def FormatRequest(method, args):
"""Formats a LUXI request message.
"""
# Build request
request = {
KEY_METHOD: method,
KEY_ARGS: args,
}
# Serialize the request
return serializer.DumpJson(request, indent=False)
def CallLuxiMethod(transport_cb, method, args):
"""Send a LUXI request via a transport and return the response.
"""
assert callable(transport_cb)
request_msg = FormatRequest(method, args)
# Send request and wait for response
response_msg = transport_cb(request_msg)
(success, result) = ParseResponse(response_msg)
if success:
return result
errors.MaybeRaise(result)
raise RequestError(result)
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.address = address
self.timeouts = timeouts
self.transport_class = transport
self.transport = None
self._InitTransport()
def _InitTransport(self):
"""(Re)initialize the transport if needed.
"""
if self.transport is None:
self.transport = self.transport_class(self.address,
timeouts=self.timeouts)
def _CloseTransport(self):
"""Close the transport, ignoring errors.
"""
if self.transport is None:
return
try:
old_transp = self.transport
self.transport = None
old_transp.Close()
def _SendMethodCall(self, data):
return self.transport.Call(data)
except Exception:
self._CloseTransport()
raise
def CallMethod(self, method, args):
"""Send a generic request and return the response.
"""
return CallLuxiMethod(self._SendMethodCall, method, args)
def SetQueueDrainFlag(self, drain_flag):
return self.CallMethod(REQ_QUEUE_SET_DRAIN_FLAG, drain_flag)
def SetWatcherPause(self, until):
return self.CallMethod(REQ_SET_WATCHER_PAUSE, [until])
def SubmitJob(self, ops):
ops_state = map(lambda op: op.__getstate__(), ops)
return self.CallMethod(REQ_SUBMIT_JOB, ops_state)
def SubmitManyJobs(self, jobs):
jobs_state = []
for ops in jobs:
jobs_state.append([op.__getstate__() for op in ops])
return self.CallMethod(REQ_SUBMIT_MANY_JOBS, jobs_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)
timeout = (DEF_RWTO - 1) / 2
return self.CallMethod(REQ_AUTOARCHIVE_JOBS, (age, timeout))
def WaitForJobChangeOnce(self, job_id, fields,
prev_job_info, prev_log_serial):
return self.CallMethod(REQ_WAIT_FOR_JOB_CHANGE,
(job_id, fields, prev_job_info,
prev_log_serial, timeout))
def WaitForJobChange(self, job_id, fields, prev_job_info, prev_log_serial):
result = self.WaitForJobChangeOnce(job_id, fields,
prev_job_info, prev_log_serial)
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, use_locking):
return self.CallMethod(REQ_QUERY_INSTANCES, (names, fields, use_locking))
def QueryNodes(self, names, fields, use_locking):
return self.CallMethod(REQ_QUERY_NODES, (names, fields, use_locking))
def QueryExports(self, nodes, use_locking):
return self.CallMethod(REQ_QUERY_EXPORTS, (nodes, use_locking))
def QueryClusterInfo(self):
return self.CallMethod(REQ_QUERY_CLUSTER_INFO, ())
def QueryConfigValues(self, fields):
return self.CallMethod(REQ_QUERY_CONFIG_VALUES, fields)
def QueryTags(self, kind, name):
return self.CallMethod(REQ_QUERY_TAGS, (kind, name))