1 # QEMU Monitor Protocol Python class
3 # Copyright (C) 2009, 2010 Red Hat Inc.
6 # Luiz Capitulino <lcapitulino@redhat.com>
8 # This work is licensed under the terms of the GNU GPL, version 2. See
9 # the COPYING file in the top-level directory.
15 class QMPError(Exception):
18 class QMPConnectError(QMPError):
21 class QMPCapabilitiesError(QMPError):
24 class QEMUMonitorProtocol:
25 def __init__(self, address):
27 Create a QEMUMonitorProtocol class.
29 @param address: QEMU address, can be either a unix socket path (string)
30 or a tuple in the form ( address, port ) for a TCP
32 @note No connection is established, this is done by the connect() method
35 self.__address = address
36 self.__sock = self.__get_sock()
37 self.__sockfile = self.__sock.makefile()
40 if isinstance(self.__address, tuple):
41 family = socket.AF_INET
43 family = socket.AF_UNIX
44 return socket.socket(family, socket.SOCK_STREAM)
46 def __json_read(self):
48 data = self.__sockfile.readline()
51 resp = json.loads(data)
53 self.__events.append(resp)
61 Connect to the QMP Monitor and perform capabilities negotiation.
63 @return QMP greeting dict
64 @raise socket.error on socket connection errors
65 @raise QMPConnectError if the greeting is not received
66 @raise QMPCapabilitiesError if fails to negotiate capabilities
68 self.__sock.connect(self.__address)
69 greeting = self.__json_read()
70 if greeting is None or not greeting.has_key('QMP'):
72 # Greeting seems ok, negotiate capabilities
73 resp = self.cmd('qmp_capabilities')
76 raise QMPCapabilitiesError
78 def cmd_obj(self, qmp_cmd):
80 Send a QMP command to the QMP Monitor.
82 @param qmp_cmd: QMP command to be sent as a Python dict
83 @return QMP response as a Python dict or None if the connection has
87 self.__sock.sendall(json.dumps(qmp_cmd))
88 except socket.error, err:
89 if err[0] == errno.EPIPE:
91 raise socket.error(err)
92 return self.__json_read()
94 def cmd(self, name, args=None, id=None):
96 Build a QMP command and send it to the QMP Monitor.
98 @param name: command name (string)
99 @param args: command arguments (dict)
100 @param id: command id (dict, list, string or int)
102 qmp_cmd = { 'execute': name }
104 qmp_cmd['arguments'] = args
107 return self.cmd_obj(qmp_cmd)
109 def get_events(self):
111 Get a list of available QMP events.
113 self.__sock.setblocking(0)
116 except socket.error, err:
117 if err[0] == errno.EAGAIN:
120 self.__sock.setblocking(1)
123 def clear_events(self):
125 Clear current list of pending events.
131 self.__sockfile.close()