Revision 904d32bc
b/Makefile.am | ||
---|---|---|
425 | 425 |
lib/hypervisor/hv_xen.py |
426 | 426 |
|
427 | 427 |
hypervisor_hv_kvm_PYTHON = \ |
428 |
lib/hypervisor/hv_kvm/__init__.py |
|
428 |
lib/hypervisor/hv_kvm/__init__.py \ |
|
429 |
lib/hypervisor/hv_kvm/monitor.py |
|
429 | 430 |
|
430 | 431 |
storage_PYTHON = \ |
431 | 432 |
lib/storage/__init__.py \ |
b/lib/hypervisor/hv_kvm/__init__.py | ||
---|---|---|
69 | 69 |
from ganeti.hypervisor import hv_base |
70 | 70 |
from ganeti.utils import wrapper as utils_wrapper |
71 | 71 |
|
72 |
from ganeti.hypervisor.hv_kvm.monitor import QmpConnection, QmpMessage, \ |
|
73 |
MonitorSocket |
|
74 |
|
|
72 | 75 |
|
73 | 76 |
_KVM_NETWORK_SCRIPT = pathutils.CONF_DIR + "/kvm-vif-bridge" |
74 | 77 |
_KVM_START_PAUSED_FLAG = "-S" |
... | ... | |
380 | 383 |
return False |
381 | 384 |
|
382 | 385 |
|
383 |
class QmpMessage: |
|
384 |
"""QEMU Messaging Protocol (QMP) message. |
|
385 |
|
|
386 |
""" |
|
387 |
def __init__(self, data): |
|
388 |
"""Creates a new QMP message based on the passed data. |
|
389 |
|
|
390 |
""" |
|
391 |
if not isinstance(data, dict): |
|
392 |
raise TypeError("QmpMessage must be initialized with a dict") |
|
393 |
|
|
394 |
self.data = data |
|
395 |
|
|
396 |
def __getitem__(self, field_name): |
|
397 |
"""Get the value of the required field if present, or None. |
|
398 |
|
|
399 |
Overrides the [] operator to provide access to the message data, |
|
400 |
returning None if the required item is not in the message |
|
401 |
@return: the value of the field_name field, or None if field_name |
|
402 |
is not contained in the message |
|
403 |
|
|
404 |
""" |
|
405 |
return self.data.get(field_name, None) |
|
406 |
|
|
407 |
def __setitem__(self, field_name, field_value): |
|
408 |
"""Set the value of the required field_name to field_value. |
|
409 |
|
|
410 |
""" |
|
411 |
self.data[field_name] = field_value |
|
412 |
|
|
413 |
def __len__(self): |
|
414 |
"""Return the number of fields stored in this QmpMessage. |
|
415 |
|
|
416 |
""" |
|
417 |
return len(self.data) |
|
418 |
|
|
419 |
def __delitem__(self, key): |
|
420 |
"""Delete the specified element from the QmpMessage. |
|
421 |
|
|
422 |
""" |
|
423 |
del(self.data[key]) |
|
424 |
|
|
425 |
@staticmethod |
|
426 |
def BuildFromJsonString(json_string): |
|
427 |
"""Build a QmpMessage from a JSON encoded string. |
|
428 |
|
|
429 |
@type json_string: str |
|
430 |
@param json_string: JSON string representing the message |
|
431 |
@rtype: L{QmpMessage} |
|
432 |
@return: a L{QmpMessage} built from json_string |
|
433 |
|
|
434 |
""" |
|
435 |
# Parse the string |
|
436 |
data = serializer.LoadJson(json_string) |
|
437 |
return QmpMessage(data) |
|
438 |
|
|
439 |
def __str__(self): |
|
440 |
# The protocol expects the JSON object to be sent as a single line. |
|
441 |
return serializer.DumpJson(self.data) |
|
442 |
|
|
443 |
def __eq__(self, other): |
|
444 |
# When comparing two QmpMessages, we are interested in comparing |
|
445 |
# their internal representation of the message data |
|
446 |
return self.data == other.data |
|
447 |
|
|
448 |
|
|
449 |
class MonitorSocket(object): |
|
450 |
_SOCKET_TIMEOUT = 5 |
|
451 |
|
|
452 |
def __init__(self, monitor_filename): |
|
453 |
"""Instantiates the MonitorSocket object. |
|
454 |
|
|
455 |
@type monitor_filename: string |
|
456 |
@param monitor_filename: the filename of the UNIX raw socket on which the |
|
457 |
monitor (QMP or simple one) is listening |
|
458 |
|
|
459 |
""" |
|
460 |
self.monitor_filename = monitor_filename |
|
461 |
self.sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) |
|
462 |
# We want to fail if the server doesn't send a complete message |
|
463 |
# in a reasonable amount of time |
|
464 |
self.sock.settimeout(self._SOCKET_TIMEOUT) |
|
465 |
self._connected = False |
|
466 |
|
|
467 |
def _check_socket(self): |
|
468 |
sock_stat = None |
|
469 |
try: |
|
470 |
sock_stat = os.stat(self.monitor_filename) |
|
471 |
except EnvironmentError, err: |
|
472 |
if err.errno == errno.ENOENT: |
|
473 |
raise errors.HypervisorError("No monitor socket found") |
|
474 |
else: |
|
475 |
raise errors.HypervisorError("Error checking monitor socket: %s", |
|
476 |
utils.ErrnoOrStr(err)) |
|
477 |
if not stat.S_ISSOCK(sock_stat.st_mode): |
|
478 |
raise errors.HypervisorError("Monitor socket is not a socket") |
|
479 |
|
|
480 |
def _check_connection(self): |
|
481 |
"""Make sure that the connection is established. |
|
482 |
|
|
483 |
""" |
|
484 |
if not self._connected: |
|
485 |
raise errors.ProgrammerError("To use a MonitorSocket you need to first" |
|
486 |
" invoke connect() on it") |
|
487 |
|
|
488 |
def connect(self): |
|
489 |
"""Connects to the monitor. |
|
490 |
|
|
491 |
Connects to the UNIX socket |
|
492 |
|
|
493 |
@raise errors.HypervisorError: when there are communication errors |
|
494 |
|
|
495 |
""" |
|
496 |
if self._connected: |
|
497 |
raise errors.ProgrammerError("Cannot connect twice") |
|
498 |
|
|
499 |
self._check_socket() |
|
500 |
|
|
501 |
# Check file existance/stuff |
|
502 |
try: |
|
503 |
self.sock.connect(self.monitor_filename) |
|
504 |
except EnvironmentError: |
|
505 |
raise errors.HypervisorError("Can't connect to qmp socket") |
|
506 |
self._connected = True |
|
507 |
|
|
508 |
def close(self): |
|
509 |
"""Closes the socket |
|
510 |
|
|
511 |
It cannot be used after this call. |
|
512 |
|
|
513 |
""" |
|
514 |
self.sock.close() |
|
515 |
|
|
516 |
|
|
517 |
class QmpConnection(MonitorSocket): |
|
518 |
"""Connection to the QEMU Monitor using the QEMU Monitor Protocol (QMP). |
|
519 |
|
|
520 |
""" |
|
521 |
_FIRST_MESSAGE_KEY = "QMP" |
|
522 |
_EVENT_KEY = "event" |
|
523 |
_ERROR_KEY = "error" |
|
524 |
_RETURN_KEY = RETURN_KEY = "return" |
|
525 |
_ACTUAL_KEY = ACTUAL_KEY = "actual" |
|
526 |
_ERROR_CLASS_KEY = "class" |
|
527 |
_ERROR_DESC_KEY = "desc" |
|
528 |
_EXECUTE_KEY = "execute" |
|
529 |
_ARGUMENTS_KEY = "arguments" |
|
530 |
_CAPABILITIES_COMMAND = "qmp_capabilities" |
|
531 |
_MESSAGE_END_TOKEN = "\r\n" |
|
532 |
|
|
533 |
def __init__(self, monitor_filename): |
|
534 |
super(QmpConnection, self).__init__(monitor_filename) |
|
535 |
self._buf = "" |
|
536 |
|
|
537 |
def connect(self): |
|
538 |
"""Connects to the QMP monitor. |
|
539 |
|
|
540 |
Connects to the UNIX socket and makes sure that we can actually send and |
|
541 |
receive data to the kvm instance via QMP. |
|
542 |
|
|
543 |
@raise errors.HypervisorError: when there are communication errors |
|
544 |
@raise errors.ProgrammerError: when there are data serialization errors |
|
545 |
|
|
546 |
""" |
|
547 |
super(QmpConnection, self).connect() |
|
548 |
# Check if we receive a correct greeting message from the server |
|
549 |
# (As per the QEMU Protocol Specification 0.1 - section 2.2) |
|
550 |
greeting = self._Recv() |
|
551 |
if not greeting[self._FIRST_MESSAGE_KEY]: |
|
552 |
self._connected = False |
|
553 |
raise errors.HypervisorError("kvm: QMP communication error (wrong" |
|
554 |
" server greeting") |
|
555 |
|
|
556 |
# This is needed because QMP can return more than one greetings |
|
557 |
# see https://groups.google.com/d/msg/ganeti-devel/gZYcvHKDooU/SnukC8dgS5AJ |
|
558 |
self._buf = "" |
|
559 |
|
|
560 |
# Let's put the monitor in command mode using the qmp_capabilities |
|
561 |
# command, or else no command will be executable. |
|
562 |
# (As per the QEMU Protocol Specification 0.1 - section 4) |
|
563 |
self.Execute(self._CAPABILITIES_COMMAND) |
|
564 |
|
|
565 |
def _ParseMessage(self, buf): |
|
566 |
"""Extract and parse a QMP message from the given buffer. |
|
567 |
|
|
568 |
Seeks for a QMP message in the given buf. If found, it parses it and |
|
569 |
returns it together with the rest of the characters in the buf. |
|
570 |
If no message is found, returns None and the whole buffer. |
|
571 |
|
|
572 |
@raise errors.ProgrammerError: when there are data serialization errors |
|
573 |
|
|
574 |
""" |
|
575 |
message = None |
|
576 |
# Check if we got the message end token (CRLF, as per the QEMU Protocol |
|
577 |
# Specification 0.1 - Section 2.1.1) |
|
578 |
pos = buf.find(self._MESSAGE_END_TOKEN) |
|
579 |
if pos >= 0: |
|
580 |
try: |
|
581 |
message = QmpMessage.BuildFromJsonString(buf[:pos + 1]) |
|
582 |
except Exception, err: |
|
583 |
raise errors.ProgrammerError("QMP data serialization error: %s" % err) |
|
584 |
buf = buf[pos + 1:] |
|
585 |
|
|
586 |
return (message, buf) |
|
587 |
|
|
588 |
def _Recv(self): |
|
589 |
"""Receives a message from QMP and decodes the received JSON object. |
|
590 |
|
|
591 |
@rtype: QmpMessage |
|
592 |
@return: the received message |
|
593 |
@raise errors.HypervisorError: when there are communication errors |
|
594 |
@raise errors.ProgrammerError: when there are data serialization errors |
|
595 |
|
|
596 |
""" |
|
597 |
self._check_connection() |
|
598 |
|
|
599 |
# Check if there is already a message in the buffer |
|
600 |
(message, self._buf) = self._ParseMessage(self._buf) |
|
601 |
if message: |
|
602 |
return message |
|
603 |
|
|
604 |
recv_buffer = StringIO.StringIO(self._buf) |
|
605 |
recv_buffer.seek(len(self._buf)) |
|
606 |
try: |
|
607 |
while True: |
|
608 |
data = self.sock.recv(4096) |
|
609 |
if not data: |
|
610 |
break |
|
611 |
recv_buffer.write(data) |
|
612 |
|
|
613 |
(message, self._buf) = self._ParseMessage(recv_buffer.getvalue()) |
|
614 |
if message: |
|
615 |
return message |
|
616 |
|
|
617 |
except socket.timeout, err: |
|
618 |
raise errors.HypervisorError("Timeout while receiving a QMP message: " |
|
619 |
"%s" % (err)) |
|
620 |
except socket.error, err: |
|
621 |
raise errors.HypervisorError("Unable to receive data from KVM using the" |
|
622 |
" QMP protocol: %s" % err) |
|
623 |
|
|
624 |
def _Send(self, message): |
|
625 |
"""Encodes and sends a message to KVM using QMP. |
|
626 |
|
|
627 |
@type message: QmpMessage |
|
628 |
@param message: message to send to KVM |
|
629 |
@raise errors.HypervisorError: when there are communication errors |
|
630 |
@raise errors.ProgrammerError: when there are data serialization errors |
|
631 |
|
|
632 |
""" |
|
633 |
self._check_connection() |
|
634 |
try: |
|
635 |
message_str = str(message) |
|
636 |
except Exception, err: |
|
637 |
raise errors.ProgrammerError("QMP data deserialization error: %s" % err) |
|
638 |
|
|
639 |
try: |
|
640 |
self.sock.sendall(message_str) |
|
641 |
except socket.timeout, err: |
|
642 |
raise errors.HypervisorError("Timeout while sending a QMP message: " |
|
643 |
"%s (%s)" % (err.string, err.errno)) |
|
644 |
except socket.error, err: |
|
645 |
raise errors.HypervisorError("Unable to send data from KVM using the" |
|
646 |
" QMP protocol: %s" % err) |
|
647 |
|
|
648 |
def Execute(self, command, arguments=None): |
|
649 |
"""Executes a QMP command and returns the response of the server. |
|
650 |
|
|
651 |
@type command: str |
|
652 |
@param command: the command to execute |
|
653 |
@type arguments: dict |
|
654 |
@param arguments: dictionary of arguments to be passed to the command |
|
655 |
@rtype: dict |
|
656 |
@return: dictionary representing the received JSON object |
|
657 |
@raise errors.HypervisorError: when there are communication errors |
|
658 |
@raise errors.ProgrammerError: when there are data serialization errors |
|
659 |
|
|
660 |
""" |
|
661 |
self._check_connection() |
|
662 |
message = QmpMessage({self._EXECUTE_KEY: command}) |
|
663 |
if arguments: |
|
664 |
message[self._ARGUMENTS_KEY] = arguments |
|
665 |
self._Send(message) |
|
666 |
|
|
667 |
# Events can occur between the sending of the command and the reception |
|
668 |
# of the response, so we need to filter out messages with the event key. |
|
669 |
while True: |
|
670 |
response = self._Recv() |
|
671 |
err = response[self._ERROR_KEY] |
|
672 |
if err: |
|
673 |
raise errors.HypervisorError("kvm: error executing the %s" |
|
674 |
" command: %s (%s):" % |
|
675 |
(command, |
|
676 |
err[self._ERROR_DESC_KEY], |
|
677 |
err[self._ERROR_CLASS_KEY])) |
|
678 |
|
|
679 |
elif not response[self._EVENT_KEY]: |
|
680 |
return response |
|
681 |
|
|
682 |
|
|
683 | 386 |
class KVMHypervisor(hv_base.BaseHypervisor): |
684 | 387 |
"""KVM hypervisor interface |
685 | 388 |
|
b/lib/hypervisor/hv_kvm/monitor.py | ||
---|---|---|
1 |
# |
|
2 |
# |
|
3 |
|
|
4 |
# Copyright (C) 2014 Google Inc. |
|
5 |
# All rights reserved. |
|
6 |
# |
|
7 |
# Redistribution and use in source and binary forms, with or without |
|
8 |
# modification, are permitted provided that the following conditions are |
|
9 |
# met: |
|
10 |
# |
|
11 |
# 1. Redistributions of source code must retain the above copyright notice, |
|
12 |
# this list of conditions and the following disclaimer. |
|
13 |
# |
|
14 |
# 2. Redistributions in binary form must reproduce the above copyright |
|
15 |
# notice, this list of conditions and the following disclaimer in the |
|
16 |
# documentation and/or other materials provided with the distribution. |
|
17 |
# |
|
18 |
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS |
|
19 |
# IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
|
20 |
# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
|
21 |
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR |
|
22 |
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
|
23 |
# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
|
24 |
# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
|
25 |
# PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
|
26 |
# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
|
27 |
# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
|
28 |
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
|
29 |
|
|
30 |
|
|
31 |
"""Qemu monitor control classes |
|
32 |
|
|
33 |
""" |
|
34 |
|
|
35 |
import os |
|
36 |
import stat |
|
37 |
import errno |
|
38 |
import socket |
|
39 |
import StringIO |
|
40 |
|
|
41 |
from ganeti import errors |
|
42 |
from ganeti import utils |
|
43 |
from ganeti import serializer |
|
44 |
|
|
45 |
|
|
46 |
class QmpMessage: |
|
47 |
"""QEMU Messaging Protocol (QMP) message. |
|
48 |
|
|
49 |
""" |
|
50 |
def __init__(self, data): |
|
51 |
"""Creates a new QMP message based on the passed data. |
|
52 |
|
|
53 |
""" |
|
54 |
if not isinstance(data, dict): |
|
55 |
raise TypeError("QmpMessage must be initialized with a dict") |
|
56 |
|
|
57 |
self.data = data |
|
58 |
|
|
59 |
def __getitem__(self, field_name): |
|
60 |
"""Get the value of the required field if present, or None. |
|
61 |
|
|
62 |
Overrides the [] operator to provide access to the message data, |
|
63 |
returning None if the required item is not in the message |
|
64 |
@return: the value of the field_name field, or None if field_name |
|
65 |
is not contained in the message |
|
66 |
|
|
67 |
""" |
|
68 |
return self.data.get(field_name, None) |
|
69 |
|
|
70 |
def __setitem__(self, field_name, field_value): |
|
71 |
"""Set the value of the required field_name to field_value. |
|
72 |
|
|
73 |
""" |
|
74 |
self.data[field_name] = field_value |
|
75 |
|
|
76 |
def __len__(self): |
|
77 |
"""Return the number of fields stored in this QmpMessage. |
|
78 |
|
|
79 |
""" |
|
80 |
return len(self.data) |
|
81 |
|
|
82 |
def __delitem__(self, key): |
|
83 |
"""Delete the specified element from the QmpMessage. |
|
84 |
|
|
85 |
""" |
|
86 |
del(self.data[key]) |
|
87 |
|
|
88 |
@staticmethod |
|
89 |
def BuildFromJsonString(json_string): |
|
90 |
"""Build a QmpMessage from a JSON encoded string. |
|
91 |
|
|
92 |
@type json_string: str |
|
93 |
@param json_string: JSON string representing the message |
|
94 |
@rtype: L{QmpMessage} |
|
95 |
@return: a L{QmpMessage} built from json_string |
|
96 |
|
|
97 |
""" |
|
98 |
# Parse the string |
|
99 |
data = serializer.LoadJson(json_string) |
|
100 |
return QmpMessage(data) |
|
101 |
|
|
102 |
def __str__(self): |
|
103 |
# The protocol expects the JSON object to be sent as a single line. |
|
104 |
return serializer.DumpJson(self.data) |
|
105 |
|
|
106 |
def __eq__(self, other): |
|
107 |
# When comparing two QmpMessages, we are interested in comparing |
|
108 |
# their internal representation of the message data |
|
109 |
return self.data == other.data |
|
110 |
|
|
111 |
|
|
112 |
class MonitorSocket(object): |
|
113 |
_SOCKET_TIMEOUT = 5 |
|
114 |
|
|
115 |
def __init__(self, monitor_filename): |
|
116 |
"""Instantiates the MonitorSocket object. |
|
117 |
|
|
118 |
@type monitor_filename: string |
|
119 |
@param monitor_filename: the filename of the UNIX raw socket on which the |
|
120 |
monitor (QMP or simple one) is listening |
|
121 |
|
|
122 |
""" |
|
123 |
self.monitor_filename = monitor_filename |
|
124 |
self.sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) |
|
125 |
# We want to fail if the server doesn't send a complete message |
|
126 |
# in a reasonable amount of time |
|
127 |
self.sock.settimeout(self._SOCKET_TIMEOUT) |
|
128 |
self._connected = False |
|
129 |
|
|
130 |
def _check_socket(self): |
|
131 |
sock_stat = None |
|
132 |
try: |
|
133 |
sock_stat = os.stat(self.monitor_filename) |
|
134 |
except EnvironmentError, err: |
|
135 |
if err.errno == errno.ENOENT: |
|
136 |
raise errors.HypervisorError("No monitor socket found") |
|
137 |
else: |
|
138 |
raise errors.HypervisorError("Error checking monitor socket: %s", |
|
139 |
utils.ErrnoOrStr(err)) |
|
140 |
if not stat.S_ISSOCK(sock_stat.st_mode): |
|
141 |
raise errors.HypervisorError("Monitor socket is not a socket") |
|
142 |
|
|
143 |
def _check_connection(self): |
|
144 |
"""Make sure that the connection is established. |
|
145 |
|
|
146 |
""" |
|
147 |
if not self._connected: |
|
148 |
raise errors.ProgrammerError("To use a MonitorSocket you need to first" |
|
149 |
" invoke connect() on it") |
|
150 |
|
|
151 |
def connect(self): |
|
152 |
"""Connects to the monitor. |
|
153 |
|
|
154 |
Connects to the UNIX socket |
|
155 |
|
|
156 |
@raise errors.HypervisorError: when there are communication errors |
|
157 |
|
|
158 |
""" |
|
159 |
if self._connected: |
|
160 |
raise errors.ProgrammerError("Cannot connect twice") |
|
161 |
|
|
162 |
self._check_socket() |
|
163 |
|
|
164 |
# Check file existance/stuff |
|
165 |
try: |
|
166 |
self.sock.connect(self.monitor_filename) |
|
167 |
except EnvironmentError: |
|
168 |
raise errors.HypervisorError("Can't connect to qmp socket") |
|
169 |
self._connected = True |
|
170 |
|
|
171 |
def close(self): |
|
172 |
"""Closes the socket |
|
173 |
|
|
174 |
It cannot be used after this call. |
|
175 |
|
|
176 |
""" |
|
177 |
self.sock.close() |
|
178 |
|
|
179 |
|
|
180 |
class QmpConnection(MonitorSocket): |
|
181 |
"""Connection to the QEMU Monitor using the QEMU Monitor Protocol (QMP). |
|
182 |
|
|
183 |
""" |
|
184 |
_FIRST_MESSAGE_KEY = "QMP" |
|
185 |
_EVENT_KEY = "event" |
|
186 |
_ERROR_KEY = "error" |
|
187 |
_RETURN_KEY = RETURN_KEY = "return" |
|
188 |
_ACTUAL_KEY = ACTUAL_KEY = "actual" |
|
189 |
_ERROR_CLASS_KEY = "class" |
|
190 |
_ERROR_DESC_KEY = "desc" |
|
191 |
_EXECUTE_KEY = "execute" |
|
192 |
_ARGUMENTS_KEY = "arguments" |
|
193 |
_CAPABILITIES_COMMAND = "qmp_capabilities" |
|
194 |
_MESSAGE_END_TOKEN = "\r\n" |
|
195 |
|
|
196 |
def __init__(self, monitor_filename): |
|
197 |
super(QmpConnection, self).__init__(monitor_filename) |
|
198 |
self._buf = "" |
|
199 |
|
|
200 |
def connect(self): |
|
201 |
"""Connects to the QMP monitor. |
|
202 |
|
|
203 |
Connects to the UNIX socket and makes sure that we can actually send and |
|
204 |
receive data to the kvm instance via QMP. |
|
205 |
|
|
206 |
@raise errors.HypervisorError: when there are communication errors |
|
207 |
@raise errors.ProgrammerError: when there are data serialization errors |
|
208 |
|
|
209 |
""" |
|
210 |
super(QmpConnection, self).connect() |
|
211 |
# Check if we receive a correct greeting message from the server |
|
212 |
# (As per the QEMU Protocol Specification 0.1 - section 2.2) |
|
213 |
greeting = self._Recv() |
|
214 |
if not greeting[self._FIRST_MESSAGE_KEY]: |
|
215 |
self._connected = False |
|
216 |
raise errors.HypervisorError("kvm: QMP communication error (wrong" |
|
217 |
" server greeting") |
|
218 |
|
|
219 |
# This is needed because QMP can return more than one greetings |
|
220 |
# see https://groups.google.com/d/msg/ganeti-devel/gZYcvHKDooU/SnukC8dgS5AJ |
|
221 |
self._buf = "" |
|
222 |
|
|
223 |
# Let's put the monitor in command mode using the qmp_capabilities |
|
224 |
# command, or else no command will be executable. |
|
225 |
# (As per the QEMU Protocol Specification 0.1 - section 4) |
|
226 |
self.Execute(self._CAPABILITIES_COMMAND) |
|
227 |
|
|
228 |
def _ParseMessage(self, buf): |
|
229 |
"""Extract and parse a QMP message from the given buffer. |
|
230 |
|
|
231 |
Seeks for a QMP message in the given buf. If found, it parses it and |
|
232 |
returns it together with the rest of the characters in the buf. |
|
233 |
If no message is found, returns None and the whole buffer. |
|
234 |
|
|
235 |
@raise errors.ProgrammerError: when there are data serialization errors |
|
236 |
|
|
237 |
""" |
|
238 |
message = None |
|
239 |
# Check if we got the message end token (CRLF, as per the QEMU Protocol |
|
240 |
# Specification 0.1 - Section 2.1.1) |
|
241 |
pos = buf.find(self._MESSAGE_END_TOKEN) |
|
242 |
if pos >= 0: |
|
243 |
try: |
|
244 |
message = QmpMessage.BuildFromJsonString(buf[:pos + 1]) |
|
245 |
except Exception, err: |
|
246 |
raise errors.ProgrammerError("QMP data serialization error: %s" % err) |
|
247 |
buf = buf[pos + 1:] |
|
248 |
|
|
249 |
return (message, buf) |
|
250 |
|
|
251 |
def _Recv(self): |
|
252 |
"""Receives a message from QMP and decodes the received JSON object. |
|
253 |
|
|
254 |
@rtype: QmpMessage |
|
255 |
@return: the received message |
|
256 |
@raise errors.HypervisorError: when there are communication errors |
|
257 |
@raise errors.ProgrammerError: when there are data serialization errors |
|
258 |
|
|
259 |
""" |
|
260 |
self._check_connection() |
|
261 |
|
|
262 |
# Check if there is already a message in the buffer |
|
263 |
(message, self._buf) = self._ParseMessage(self._buf) |
|
264 |
if message: |
|
265 |
return message |
|
266 |
|
|
267 |
recv_buffer = StringIO.StringIO(self._buf) |
|
268 |
recv_buffer.seek(len(self._buf)) |
|
269 |
try: |
|
270 |
while True: |
|
271 |
data = self.sock.recv(4096) |
|
272 |
if not data: |
|
273 |
break |
|
274 |
recv_buffer.write(data) |
|
275 |
|
|
276 |
(message, self._buf) = self._ParseMessage(recv_buffer.getvalue()) |
|
277 |
if message: |
|
278 |
return message |
|
279 |
|
|
280 |
except socket.timeout, err: |
|
281 |
raise errors.HypervisorError("Timeout while receiving a QMP message: " |
|
282 |
"%s" % (err)) |
|
283 |
except socket.error, err: |
|
284 |
raise errors.HypervisorError("Unable to receive data from KVM using the" |
|
285 |
" QMP protocol: %s" % err) |
|
286 |
|
|
287 |
def _Send(self, message): |
|
288 |
"""Encodes and sends a message to KVM using QMP. |
|
289 |
|
|
290 |
@type message: QmpMessage |
|
291 |
@param message: message to send to KVM |
|
292 |
@raise errors.HypervisorError: when there are communication errors |
|
293 |
@raise errors.ProgrammerError: when there are data serialization errors |
|
294 |
|
|
295 |
""" |
|
296 |
self._check_connection() |
|
297 |
try: |
|
298 |
message_str = str(message) |
|
299 |
except Exception, err: |
|
300 |
raise errors.ProgrammerError("QMP data deserialization error: %s" % err) |
|
301 |
|
|
302 |
try: |
|
303 |
self.sock.sendall(message_str) |
|
304 |
except socket.timeout, err: |
|
305 |
raise errors.HypervisorError("Timeout while sending a QMP message: " |
|
306 |
"%s (%s)" % (err.string, err.errno)) |
|
307 |
except socket.error, err: |
|
308 |
raise errors.HypervisorError("Unable to send data from KVM using the" |
|
309 |
" QMP protocol: %s" % err) |
|
310 |
|
|
311 |
def Execute(self, command, arguments=None): |
|
312 |
"""Executes a QMP command and returns the response of the server. |
|
313 |
|
|
314 |
@type command: str |
|
315 |
@param command: the command to execute |
|
316 |
@type arguments: dict |
|
317 |
@param arguments: dictionary of arguments to be passed to the command |
|
318 |
@rtype: dict |
|
319 |
@return: dictionary representing the received JSON object |
|
320 |
@raise errors.HypervisorError: when there are communication errors |
|
321 |
@raise errors.ProgrammerError: when there are data serialization errors |
|
322 |
|
|
323 |
""" |
|
324 |
self._check_connection() |
|
325 |
message = QmpMessage({self._EXECUTE_KEY: command}) |
|
326 |
if arguments: |
|
327 |
message[self._ARGUMENTS_KEY] = arguments |
|
328 |
self._Send(message) |
|
329 |
|
|
330 |
# Events can occur between the sending of the command and the reception |
|
331 |
# of the response, so we need to filter out messages with the event key. |
|
332 |
while True: |
|
333 |
response = self._Recv() |
|
334 |
err = response[self._ERROR_KEY] |
|
335 |
if err: |
|
336 |
raise errors.HypervisorError("kvm: error executing the %s" |
|
337 |
" command: %s (%s):" % |
|
338 |
(command, |
|
339 |
err[self._ERROR_DESC_KEY], |
|
340 |
err[self._ERROR_CLASS_KEY])) |
|
341 |
|
|
342 |
elif not response[self._EVENT_KEY]: |
|
343 |
return response |
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