| """ |
| Interfaces to the QEMU monitor. |
| |
| @copyright: 2008-2010 Red Hat Inc. |
| """ |
| |
| import socket, time, threading, logging, select |
| import virt_utils |
| try: |
| import json |
| except ImportError: |
| logging.warning("Could not import json module. " |
| "QMP monitor functionality disabled.") |
| |
| |
| class MonitorError(Exception): |
| pass |
| |
| |
| class MonitorConnectError(MonitorError): |
| pass |
| |
| |
| class MonitorSocketError(MonitorError): |
| def __init__(self, msg, e): |
| Exception.__init__(self, msg, e) |
| self.msg = msg |
| self.e = e |
| |
| def __str__(self): |
| return "%s (%s)" % (self.msg, self.e) |
| |
| |
| class MonitorLockError(MonitorError): |
| pass |
| |
| |
| class MonitorProtocolError(MonitorError): |
| pass |
| |
| |
| class MonitorNotSupportedError(MonitorError): |
| pass |
| |
| |
| class QMPCmdError(MonitorError): |
| def __init__(self, cmd, qmp_args, data): |
| MonitorError.__init__(self, cmd, qmp_args, data) |
| self.cmd = cmd |
| self.qmp_args = qmp_args |
| self.data = data |
| |
| def __str__(self): |
| return ("QMP command %r failed (arguments: %r, " |
| "error message: %r)" % (self.cmd, self.qmp_args, self.data)) |
| |
| |
| class Monitor: |
| """ |
| Common code for monitor classes. |
| """ |
| |
| def __init__(self, name, filename): |
| """ |
| Initialize the instance. |
| |
| @param name: Monitor identifier (a string) |
| @param filename: Monitor socket filename |
| @raise MonitorConnectError: Raised if the connection fails |
| """ |
| self.name = name |
| self.filename = filename |
| self._lock = threading.RLock() |
| self._socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) |
| |
| try: |
| self._socket.connect(filename) |
| except socket.error: |
| raise MonitorConnectError("Could not connect to monitor socket") |
| |
| |
| def __del__(self): |
| # Automatically close the connection when the instance is garbage |
| # collected |
| self._close_sock() |
| |
| |
| # The following two functions are defined to make sure the state is set |
| # exclusively by the constructor call as specified in __getinitargs__(). |
| |
| def __getstate__(self): |
| pass |
| |
| |
| def __setstate__(self, state): |
| pass |
| |
| |
| def __getinitargs__(self): |
| # Save some information when pickling -- will be passed to the |
| # constructor upon unpickling |
| return self.name, self.filename, True |
| |
| |
| def _close_sock(self): |
| try: |
| self._socket.shutdown(socket.SHUT_RDWR) |
| except socket.error: |
| pass |
| self._socket.close() |
| |
| def _acquire_lock(self, timeout=20): |
| end_time = time.time() + timeout |
| while time.time() < end_time: |
| if self._lock.acquire(False): |
| return True |
| time.sleep(0.05) |
| return False |
| |
| |
| def _data_available(self, timeout=0): |
| timeout = max(0, timeout) |
| try: |
| return bool(select.select([self._socket], [], [], timeout)[0]) |
| except socket.error, e: |
| raise MonitorSocketError("Verifying data on monitor socket", e) |
| |
| |
| def _recvall(self): |
| s = "" |
| while self._data_available(): |
| try: |
| data = self._socket.recv(1024) |
| except socket.error, e: |
| raise MonitorSocketError("Could not receive data from monitor", |
| e) |
| if not data: |
| break |
| s += data |
| return s |
| |
| |
| def is_responsive(self): |
| """ |
| Return True iff the monitor is responsive. |
| """ |
| try: |
| self.verify_responsive() |
| return True |
| except MonitorError: |
| return False |
| |
| |
| class HumanMonitor(Monitor): |
| """ |
| Wraps "human monitor" commands. |
| """ |
| |
| def __init__(self, name, filename, suppress_exceptions=False): |
| """ |
| Connect to the monitor socket and find the (qemu) prompt. |
| |
| @param name: Monitor identifier (a string) |
| @param filename: Monitor socket filename |
| @raise MonitorConnectError: Raised if the connection fails and |
| suppress_exceptions is False |
| @raise MonitorProtocolError: Raised if the initial (qemu) prompt isn't |
| found and suppress_exceptions is False |
| @note: Other exceptions may be raised. See cmd()'s |
| docstring. |
| """ |
| try: |
| Monitor.__init__(self, name, filename) |
| |
| self.protocol = "human" |
| |
| # Find the initial (qemu) prompt |
| s, o = self._read_up_to_qemu_prompt(20) |
| if not s: |
| raise MonitorProtocolError("Could not find (qemu) prompt " |
| "after connecting to monitor. " |
| "Output so far: %r" % o) |
| |
| # Save the output of 'help' for future use |
| self._help_str = self.cmd("help", debug=False) |
| |
| except MonitorError, e: |
| self._close_sock() |
| if suppress_exceptions: |
| logging.warning(e) |
| else: |
| raise |
| |
| |
| # Private methods |
| |
| def _read_up_to_qemu_prompt(self, timeout=20): |
| s = "" |
| end_time = time.time() + timeout |
| while self._data_available(end_time - time.time()): |
| data = self._recvall() |
| if not data: |
| break |
| s += data |
| try: |
| if s.splitlines()[-1].split()[-1] == "(qemu)": |
| return True, "\n".join(s.splitlines()[:-1]) |
| except IndexError: |
| continue |
| return False, "\n".join(s.splitlines()) |
| |
| |
| def _send(self, cmd): |
| """ |
| Send a command without waiting for output. |
| |
| @param cmd: Command to send |
| @raise MonitorLockError: Raised if the lock cannot be acquired |
| @raise MonitorSocketError: Raised if a socket error occurs |
| """ |
| if not self._acquire_lock(20): |
| raise MonitorLockError("Could not acquire exclusive lock to send " |
| "monitor command '%s'" % cmd) |
| |
| try: |
| try: |
| self._socket.sendall(cmd + "\n") |
| except socket.error, e: |
| raise MonitorSocketError("Could not send monitor command %r" % |
| cmd, e) |
| |
| finally: |
| self._lock.release() |
| |
| |
| # Public methods |
| |
| def cmd(self, command, timeout=20, debug=True): |
| """ |
| Send command to the monitor. |
| |
| @param command: Command to send to the monitor |
| @param timeout: Time duration to wait for the (qemu) prompt to return |
| @param debug: Whether to print the commands being sent and responses |
| @return: Output received from the monitor |
| @raise MonitorLockError: Raised if the lock cannot be acquired |
| @raise MonitorSocketError: Raised if a socket error occurs |
| @raise MonitorProtocolError: Raised if the (qemu) prompt cannot be |
| found after sending the command |
| """ |
| if debug: |
| logging.debug("(monitor %s) Sending command '%s'", |
| self.name, command) |
| if not self._acquire_lock(20): |
| raise MonitorLockError("Could not acquire exclusive lock to send " |
| "monitor command '%s'" % command) |
| |
| try: |
| # Read any data that might be available |
| self._recvall() |
| # Send command |
| self._send(command) |
| # Read output |
| s, o = self._read_up_to_qemu_prompt(timeout) |
| # Remove command echo from output |
| o = "\n".join(o.splitlines()[1:]) |
| # Report success/failure |
| if s: |
| if debug and o: |
| logging.debug("(monitor %s) " |
| "Response to '%s'", self.name, |
| command) |
| for l in o.splitlines(): |
| logging.debug("(monitor %s) %s", self.name, l) |
| return o |
| else: |
| msg = ("Could not find (qemu) prompt after command '%s'. " |
| "Output so far: %r" % (command, o)) |
| raise MonitorProtocolError(msg) |
| |
| finally: |
| self._lock.release() |
| |
| |
| def verify_responsive(self): |
| """ |
| Make sure the monitor is responsive by sending a command. |
| """ |
| self.cmd("info status", debug=False) |
| |
| |
| def verify_status(self, status): |
| """ |
| Verify VM status |
| |
| @param status: Optional VM status, 'running' or 'paused' |
| @return: return True if VM status is same as we expected |
| """ |
| o = self.cmd("info status", debug=False) |
| if status=='paused' or status=='running': |
| return (status in o) |
| |
| |
| # Command wrappers |
| # Notes: |
| # - All of the following commands raise exceptions in a similar manner to |
| # cmd(). |
| # - A command wrapper should use self._help_str if it requires information |
| # about the monitor's capabilities. |
| |
| def quit(self): |
| """ |
| Send "quit" without waiting for output. |
| """ |
| self._send("quit") |
| |
| |
| def info(self, what): |
| """ |
| Request info about something and return the output. |
| """ |
| return self.cmd("info %s" % what) |
| |
| |
| def query(self, what): |
| """ |
| Alias for info. |
| """ |
| return self.info(what) |
| |
| |
| def screendump(self, filename, debug=True): |
| """ |
| Request a screendump. |
| |
| @param filename: Location for the screendump |
| @return: The command's output |
| """ |
| return self.cmd(command="screendump %s" % filename, debug=debug) |
| |
| |
| def migrate(self, uri, full_copy=False, incremental_copy=False, wait=False): |
| """ |
| Migrate. |
| |
| @param uri: destination URI |
| @param full_copy: If true, migrate with full disk copy |
| @param incremental_copy: If true, migrate with incremental disk copy |
| @param wait: If true, wait for completion |
| @return: The command's output |
| """ |
| cmd = "migrate" |
| if not wait: |
| cmd += " -d" |
| if full_copy: |
| cmd += " -b" |
| if incremental_copy: |
| cmd += " -i" |
| cmd += " %s" % uri |
| return self.cmd(cmd) |
| |
| |
| def migrate_set_speed(self, value): |
| """ |
| Set maximum speed (in bytes/sec) for migrations. |
| |
| @param value: Speed in bytes/sec |
| @return: The command's output |
| """ |
| return self.cmd("migrate_set_speed %s" % value) |
| |
| |
| def sendkey(self, keystr, hold_time=1): |
| """ |
| Send key combination to VM. |
| |
| @param keystr: Key combination string |
| @param hold_time: Hold time in ms (should normally stay 1 ms) |
| @return: The command's output |
| """ |
| return self.cmd("sendkey %s %s" % (keystr, hold_time)) |
| |
| |
| def mouse_move(self, dx, dy): |
| """ |
| Move mouse. |
| |
| @param dx: X amount |
| @param dy: Y amount |
| @return: The command's output |
| """ |
| return self.cmd("mouse_move %d %d" % (dx, dy)) |
| |
| |
| def mouse_button(self, state): |
| """ |
| Set mouse button state. |
| |
| @param state: Button state (1=L, 2=M, 4=R) |
| @return: The command's output |
| """ |
| return self.cmd("mouse_button %d" % state) |
| |
| |
| class QMPMonitor(Monitor): |
| """ |
| Wraps QMP monitor commands. |
| """ |
| |
| def __init__(self, name, filename, suppress_exceptions=False): |
| """ |
| Connect to the monitor socket, read the greeting message and issue the |
| qmp_capabilities command. Also make sure the json module is available. |
| |
| @param name: Monitor identifier (a string) |
| @param filename: Monitor socket filename |
| @raise MonitorConnectError: Raised if the connection fails and |
| suppress_exceptions is False |
| @raise MonitorProtocolError: Raised if the no QMP greeting message is |
| received and suppress_exceptions is False |
| @raise MonitorNotSupportedError: Raised if json isn't available and |
| suppress_exceptions is False |
| @note: Other exceptions may be raised if the qmp_capabilities command |
| fails. See cmd()'s docstring. |
| """ |
| try: |
| Monitor.__init__(self, name, filename) |
| |
| self.protocol = "qmp" |
| self._greeting = None |
| self._events = [] |
| |
| # Make sure json is available |
| try: |
| json |
| except NameError: |
| raise MonitorNotSupportedError("QMP requires the json module " |
| "(Python 2.6 and up)") |
| |
| # Read greeting message |
| end_time = time.time() + 20 |
| while time.time() < end_time: |
| for obj in self._read_objects(): |
| if "QMP" in obj: |
| self._greeting = obj |
| break |
| if self._greeting: |
| break |
| time.sleep(0.1) |
| else: |
| raise MonitorProtocolError("No QMP greeting message received") |
| |
| # Issue qmp_capabilities |
| self.cmd("qmp_capabilities") |
| |
| except MonitorError, e: |
| self._close_sock() |
| if suppress_exceptions: |
| logging.warning(e) |
| else: |
| raise |
| |
| |
| # Private methods |
| |
| def _build_cmd(self, cmd, args=None, id=None): |
| obj = {"execute": cmd} |
| if args is not None: |
| obj["arguments"] = args |
| if id is not None: |
| obj["id"] = id |
| return obj |
| |
| |
| def _read_objects(self, timeout=5): |
| """ |
| Read lines from the monitor and try to decode them. |
| Stop when all available lines have been successfully decoded, or when |
| timeout expires. If any decoded objects are asynchronous events, store |
| them in self._events. Return all decoded objects. |
| |
| @param timeout: Time to wait for all lines to decode successfully |
| @return: A list of objects |
| """ |
| if not self._data_available(): |
| return [] |
| s = "" |
| end_time = time.time() + timeout |
| while self._data_available(end_time - time.time()): |
| s += self._recvall() |
| # Make sure all lines are decodable |
| for line in s.splitlines(): |
| if line: |
| try: |
| json.loads(line) |
| except: |
| # Found an incomplete or broken line -- keep reading |
| break |
| else: |
| # All lines are OK -- stop reading |
| break |
| # Decode all decodable lines |
| objs = [] |
| for line in s.splitlines(): |
| try: |
| objs += [json.loads(line)] |
| except: |
| pass |
| # Keep track of asynchronous events |
| self._events += [obj for obj in objs if "event" in obj] |
| return objs |
| |
| |
| def _send(self, data): |
| """ |
| Send raw data without waiting for response. |
| |
| @param data: Data to send |
| @raise MonitorSocketError: Raised if a socket error occurs |
| """ |
| try: |
| self._socket.sendall(data) |
| except socket.error, e: |
| raise MonitorSocketError("Could not send data: %r" % data, e) |
| |
| |
| def _get_response(self, id=None, timeout=20): |
| """ |
| Read a response from the QMP monitor. |
| |
| @param id: If not None, look for a response with this id |
| @param timeout: Time duration to wait for response |
| @return: The response dict, or None if none was found |
| """ |
| end_time = time.time() + timeout |
| while self._data_available(end_time - time.time()): |
| for obj in self._read_objects(): |
| if isinstance(obj, dict): |
| if id is not None and obj.get("id") != id: |
| continue |
| if "return" in obj or "error" in obj: |
| return obj |
| |
| |
| # Public methods |
| |
| def cmd(self, cmd, args=None, timeout=20, debug=True): |
| """ |
| Send a QMP monitor command and return the response. |
| |
| Note: an id is automatically assigned to the command and the response |
| is checked for the presence of the same id. |
| |
| @param cmd: Command to send |
| @param args: A dict containing command arguments, or None |
| @param timeout: Time duration to wait for response |
| @return: The response received |
| @raise MonitorLockError: Raised if the lock cannot be acquired |
| @raise MonitorSocketError: Raised if a socket error occurs |
| @raise MonitorProtocolError: Raised if no response is received |
| @raise QMPCmdError: Raised if the response is an error message |
| (the exception's args are (cmd, args, data) where data is the |
| error data) |
| """ |
| if debug: |
| logging.debug("(monitor %s) Sending command '%s'", |
| self.name, cmd) |
| if not self._acquire_lock(20): |
| raise MonitorLockError("Could not acquire exclusive lock to send " |
| "QMP command '%s'" % cmd) |
| |
| try: |
| # Read any data that might be available |
| self._read_objects() |
| # Send command |
| id = virt_utils.generate_random_string(8) |
| self._send(json.dumps(self._build_cmd(cmd, args, id)) + "\n") |
| # Read response |
| r = self._get_response(id, timeout) |
| if r is None: |
| raise MonitorProtocolError("Received no response to QMP " |
| "command '%s', or received a " |
| "response with an incorrect id" |
| % cmd) |
| if "return" in r: |
| if debug and r["return"]: |
| logging.debug("(monitor %s) " |
| "Response to '%s'", self.name, cmd) |
| o = str(r["return"]) |
| for l in o.splitlines(): |
| logging.debug("(monitor %s) %s", self.name, l) |
| return r["return"] |
| if "error" in r: |
| raise QMPCmdError(cmd, args, r["error"]) |
| |
| finally: |
| self._lock.release() |
| |
| |
| def cmd_raw(self, data, timeout=20): |
| """ |
| Send a raw string to the QMP monitor and return the response. |
| Unlike cmd(), return the raw response dict without performing any |
| checks on it. |
| |
| @param data: The data to send |
| @param timeout: Time duration to wait for response |
| @return: The response received |
| @raise MonitorLockError: Raised if the lock cannot be acquired |
| @raise MonitorSocketError: Raised if a socket error occurs |
| @raise MonitorProtocolError: Raised if no response is received |
| """ |
| if not self._acquire_lock(20): |
| raise MonitorLockError("Could not acquire exclusive lock to send " |
| "data: %r" % data) |
| |
| try: |
| self._read_objects() |
| self._send(data) |
| r = self._get_response(None, timeout) |
| if r is None: |
| raise MonitorProtocolError("Received no response to data: %r" % |
| data) |
| return r |
| |
| finally: |
| self._lock.release() |
| |
| |
| def cmd_obj(self, obj, timeout=20): |
| """ |
| Transform a Python object to JSON, send the resulting string to the QMP |
| monitor, and return the response. |
| Unlike cmd(), return the raw response dict without performing any |
| checks on it. |
| |
| @param obj: The object to send |
| @param timeout: Time duration to wait for response |
| @return: The response received |
| @raise MonitorLockError: Raised if the lock cannot be acquired |
| @raise MonitorSocketError: Raised if a socket error occurs |
| @raise MonitorProtocolError: Raised if no response is received |
| """ |
| return self.cmd_raw(json.dumps(obj) + "\n") |
| |
| |
| def cmd_qmp(self, cmd, args=None, id=None, timeout=20): |
| """ |
| Build a QMP command from the passed arguments, send it to the monitor |
| and return the response. |
| Unlike cmd(), return the raw response dict without performing any |
| checks on it. |
| |
| @param cmd: Command to send |
| @param args: A dict containing command arguments, or None |
| @param id: An id for the command, or None |
| @param timeout: Time duration to wait for response |
| @return: The response received |
| @raise MonitorLockError: Raised if the lock cannot be acquired |
| @raise MonitorSocketError: Raised if a socket error occurs |
| @raise MonitorProtocolError: Raised if no response is received |
| """ |
| return self.cmd_obj(self._build_cmd(cmd, args, id), timeout) |
| |
| |
| def verify_responsive(self): |
| """ |
| Make sure the monitor is responsive by sending a command. |
| """ |
| self.cmd(cmd="query-status", debug=False) |
| |
| |
| def verify_status(self, status): |
| """ |
| Verify VM status |
| |
| @param status: Optional VM status, 'running' or 'paused' |
| @return: return True if VM status is same as we expected |
| """ |
| o = str(self.cmd(cmd="query-status", debug=False)) |
| if (status=='paused' and "u'running': False" in o): |
| return True |
| if (status=='running' and "u'running': True" in o): |
| return True |
| |
| |
| def get_events(self): |
| """ |
| Return a list of the asynchronous events received since the last |
| clear_events() call. |
| |
| @return: A list of events (the objects returned have an "event" key) |
| @raise MonitorLockError: Raised if the lock cannot be acquired |
| """ |
| if not self._acquire_lock(20): |
| raise MonitorLockError("Could not acquire exclusive lock to read " |
| "QMP events") |
| try: |
| self._read_objects() |
| return self._events[:] |
| finally: |
| self._lock.release() |
| |
| |
| def get_event(self, name): |
| """ |
| Look for an event with the given name in the list of events. |
| |
| @param name: The name of the event to look for (e.g. 'RESET') |
| @return: An event object or None if none is found |
| """ |
| for e in self.get_events(): |
| if e.get("event") == name: |
| return e |
| |
| |
| def clear_events(self): |
| """ |
| Clear the list of asynchronous events. |
| |
| @raise MonitorLockError: Raised if the lock cannot be acquired |
| """ |
| if not self._acquire_lock(20): |
| raise MonitorLockError("Could not acquire exclusive lock to clear " |
| "QMP event list") |
| self._events = [] |
| self._lock.release() |
| |
| |
| def get_greeting(self): |
| """ |
| Return QMP greeting message. |
| """ |
| return self._greeting |
| |
| |
| # Command wrappers |
| # Note: all of the following functions raise exceptions in a similar manner |
| # to cmd(). |
| |
| def quit(self): |
| """ |
| Send "quit" and return the response. |
| """ |
| return self.cmd("quit") |
| |
| |
| def info(self, what): |
| """ |
| Request info about something and return the response. |
| """ |
| return self.cmd("query-%s" % what) |
| |
| |
| def query(self, what): |
| """ |
| Alias for info. |
| """ |
| return self.info(what) |
| |
| |
| def screendump(self, filename, debug=True): |
| """ |
| Request a screendump. |
| |
| @param filename: Location for the screendump |
| @return: The response to the command |
| """ |
| args = {"filename": filename} |
| return self.cmd(cmd="screendump", args=args, debug=debug) |
| |
| |
| def migrate(self, uri, full_copy=False, incremental_copy=False, wait=False): |
| """ |
| Migrate. |
| |
| @param uri: destination URI |
| @param full_copy: If true, migrate with full disk copy |
| @param incremental_copy: If true, migrate with incremental disk copy |
| @param wait: If true, wait for completion |
| @return: The response to the command |
| """ |
| args = {"uri": uri, |
| "blk": full_copy, |
| "inc": incremental_copy} |
| return self.cmd("migrate", args) |
| |
| |
| def migrate_set_speed(self, value): |
| """ |
| Set maximum speed (in bytes/sec) for migrations. |
| |
| @param value: Speed in bytes/sec |
| @return: The response to the command |
| """ |
| args = {"value": value} |
| return self.cmd("migrate_set_speed", args) |
