qemu.machine.machine module

QEMU machine module:

The machine module primarily provides the QEMUMachine class, which provides facilities for managing the lifetime of a QEMU VM.

exception qemu.machine.machine.AbnormalShutdown

Bases: qemu.machine.machine.QEMUMachineError

Exception raised when a graceful shutdown was requested, but not performed.

class qemu.machine.machine.QEMUMachine(binary: str, args: Sequence[str] = (), wrapper: Sequence[str] = (), name: Optional[str] = None, base_temp_dir: str = '/var/tmp', monitor_address: Optional[Union[Tuple[str, int], str]] = None, socket_scm_helper: Optional[str] = None, sock_dir: Optional[str] = None, drain_console: bool = False, console_log: Optional[str] = None, log_dir: Optional[str] = None, qmp_timer: Optional[float] = None)

Bases: object

A QEMU VM.

Use this object as a context manager to ensure the QEMU process terminates:

with VM(binary) as vm:
    ...
# vm is guaranteed to be shut down here

add_args(*args: str) → None

Adds to the list of extra arguments to be given to the QEMU binary

add_fd(fd: int, fdset: int, opaque: str, opts: str = '') → qemu.machine.machine._T

Pass a file descriptor to the VM

add_monitor_null() → None

This can be used to add an unused monitor instance.

property args: List[str]

Returns the list of arguments given to the QEMU binary.

command(cmd: str, conv_keys: bool = True, **args: Any) → object

Invoke a QMP command. On success return the response dict. On failure raise an exception.

property console_socket: socket.socket

Returns a socket connected to the console

static event_match(event: Any, match: Optional[Any]) → bool

Check if an event matches optional match criteria.

The match criteria takes the form of a matching subdict. The event is checked to be a superset of the subdict, recursively, with matching values whenever the subdict values are not None.

This has a limitation that you cannot explicitly check for None values.

Examples, with the subdict queries on the left:

• None matches any object.

• {“foo”: None} matches {“foo”: {“bar”: 1}}

• {“foo”: None} matches {“foo”: 5}

• {“foo”: {“abc”: None}} does not match {“foo”: {“bar”: 1}}

• {“foo”: {“rab”: 2}} matches {“foo”: {“bar”: 1, “rab”: 2}}

event_wait(name: str, timeout: float = 60.0, match: Optional[Dict[str, Any]] = None) → Optional[Dict[str, Any]]

event_wait waits for and returns a named event from QMP with a timeout.

name: The event to wait for. timeout: QEMUMonitorProtocol.pull_event timeout parameter. match: Optional match criteria. See event_match for details.

events_wait(events: Sequence[Tuple[str, Any]], timeout: float = 60.0) → Optional[Dict[str, Any]]

events_wait waits for and returns a single named event from QMP. In the case of multiple qualifying events, this function returns the first one.

Parameters

• events – A sequence of (name, match_criteria) tuples. The match criteria are optional and may be None. See event_match for details.

• timeout – Optional timeout, in seconds. See QEMUMonitorProtocol.pull_event.

Raises

QMPTimeoutError – If timeout was non-zero and no matching events were found.

Returns

A QMP event matching the filter criteria. If timeout was 0 and no event matched, None.

exitcode() → Optional[int]

Returns the exit code if possible, or None.

get_log() → Optional[str]

After self.shutdown or failed qemu execution, this returns the output of the qemu process.

get_pid() → Optional[int]

Returns the PID of the running process, or None.

get_qmp_event(wait: bool = False) → Optional[Dict[str, Any]]

Poll for one queued QMP events and return it

get_qmp_events(wait: bool = False) → List[Dict[str, Any]]

Poll for queued QMP events and return a list of dicts

is_running() → bool

Returns true if the VM is running.

kill() → None

Terminate the VM forcefully, wait for it to exit, and perform cleanup.

launch() → None

Launch the VM and make sure we cleanup and expose the command line/output in case of exception

property log_dir: str

Returns a directory to be used for writing logs

qmp(cmd: str, args_dict: Optional[Dict[str, object]] = None, conv_keys: Optional[bool] = None, **args: Any) → Dict[str, Any]

Invoke a QMP command and return the response dict

send_fd_scm(fd: Optional[int] = None, file_path: Optional[str] = None) → int

Send an fd or file_path to socket_scm_helper.

Exactly one of fd and file_path must be given. If it is file_path, the helper will open that file and pass its own fd.

set_console(device_type: Optional[str] = None, console_index: int = 0) → None

Sets the device type for a console device

If set, the console device and a backing character device will be added to the base arguments of the resulting QEMU command line.

This is a convenience method that will either use the provided device type, or default to a “-serial chardev:console” command line argument.

The actual setting of command line arguments will be be done at machine launch time, as it depends on the temporary directory to be created.

@param device_type: the device type, such as “isa-serial”. If

None is given (the default value) a “-serial chardev:console” command line argument will be used instead, resorting to the machine’s default device type.

@param console_index: the index of the console device to use.

If not zero, the command line will create ‘index - 1’ consoles and connect them to the ‘null’ backing character device.

set_machine(machine_type: str) → None

Sets the machine type

If set, the machine type will be added to the base arguments of the resulting QEMU command line.

set_qmp_monitor(enabled: bool = True) → None

Set the QMP monitor.

@param enabled: if False, qmp monitor options will be removed from

the base arguments of the resulting QEMU command line. Default is True.

Note

Call this function before launch().

shutdown(has_quit: bool = False, hard: bool = False, timeout: Optional[int] = 30) → None

Terminate the VM (gracefully if possible) and perform cleanup. Cleanup will always be performed.

If the VM has not yet been launched, or shutdown(), wait(), or kill() have already been called, this method does nothing.

Parameters

• has_quit – When true, do not attempt to issue ‘quit’ QMP command.

• hard – When true, do not attempt graceful shutdown, and suppress the SIGKILL warning log message.

• timeout – Optional timeout in seconds for graceful shutdown. Default 30 seconds, A None value is an infinite wait.

property temp_dir: str

Returns a temporary directory to be used for this machine

wait(timeout: Optional[int] = 30) → None

Wait for the VM to power off and perform post-shutdown cleanup.

Parameters

timeout – Optional timeout in seconds. Default 30 seconds. A value of None is an infinite wait.

exception qemu.machine.machine.QEMUMachineAddDeviceError

Bases: qemu.machine.machine.QEMUMachineError

Exception raised when a request to add a device can not be fulfilled

The failures are caused by limitations, lack of information or conflicting requests on the QEMUMachine methods. This exception does not represent failures reported by the QEMU binary itself.

exception qemu.machine.machine.QEMUMachineError

Bases: Exception

Exception called when an error in QEMUMachine happens.