python/qemu: Add mypy type annotations

These should all be purely annotations with no changes in behavior at
all. You need to be in the python folder, but you should be able to
confirm that these annotations are correct (or at least self-consistent)
by running `mypy --strict qemu`.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 20201006235817.3280413-12-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>

4 files changed, 101 insertions, 75 deletions

diff --git a/python/qemu/accel.py b/python/qemu/accel.py
index 3ec6bdcfdb..297933df2a 100644
--- a/python/qemu/accel.py
+++ b/python/qemu/accel.py
@@ -17,6 +17,7 @@ accelerators.
 import logging
 import os
 import subprocess
+from typing import List, Optional
 
 
 LOG = logging.getLogger(__name__)
@@ -30,7 +31,7 @@ ADDITIONAL_ARCHES = {
 }
 
 
-def list_accel(qemu_bin):
+def list_accel(qemu_bin: str) -> List[str]:
     """
     List accelerators enabled in the QEMU binary.
 
@@ -50,7 +51,8 @@ def list_accel(qemu_bin):
     return [acc.strip() for acc in out.splitlines()[1:]]
 
 
-def kvm_available(target_arch=None, qemu_bin=None):
+def kvm_available(target_arch: Optional[str] = None,
+                  qemu_bin: Optional[str] = None) -> bool:
     """
     Check if KVM is available using the following heuristic:
       - Kernel module is present in the host;
@@ -73,7 +75,7 @@ def kvm_available(target_arch=None, qemu_bin=None):
     return True
 
 
-def tcg_available(qemu_bin):
+def tcg_available(qemu_bin: str) -> bool:
     """
     Check if TCG is available.
 
diff --git a/python/qemu/machine.py b/python/qemu/machine.py
index e599cb7439..6420f01bed 100644
--- a/python/qemu/machine.py
+++ b/python/qemu/machine.py
@@ -23,11 +23,13 @@ import logging
 import os
 import shutil
 import signal
+import socket
 import subprocess
 import tempfile
 from types import TracebackType
 from typing import (
     Any,
+    BinaryIO,
     Dict,
     List,
     Optional,
@@ -37,7 +39,7 @@ from typing import (
 )
 
 from . import console_socket, qmp
-from .qmp import QMPMessage, SocketAddrT
+from .qmp import QMPMessage, QMPReturnValue, SocketAddrT
 
 
 LOG = logging.getLogger(__name__)
@@ -67,7 +69,7 @@ class AbnormalShutdown(QEMUMachineError):
 
 class QEMUMachine:
     """
-    A QEMU VM
+    A QEMU VM.
 
     Use this object as a context manager to ensure
     the QEMU process terminates::
@@ -84,8 +86,10 @@ class QEMUMachine:
                  name: Optional[str] = None,
                  test_dir: str = "/var/tmp",
                  monitor_address: Optional[SocketAddrT] = None,
-                 socket_scm_helper=None, sock_dir=None,
-                 drain_console=False, console_log=None):
+                 socket_scm_helper: Optional[str] = None,
+                 sock_dir: Optional[str] = None,
+                 drain_console: bool = False,
+                 console_log: Optional[str] = None):
         '''
         Initialize a QEMUMachine
 
@@ -129,28 +133,28 @@ class QEMUMachine:
             self._drain_console = drain_console
 
         # Runstate
-        self._qemu_log_path = None
-        self._qemu_log_file = None
+        self._qemu_log_path: Optional[str] = None
+        self._qemu_log_file: Optional[BinaryIO] = None
         self._popen: Optional['subprocess.Popen[bytes]'] = None
-        self._events = []
-        self._iolog = None
+        self._events: List[QMPMessage] = []
+        self._iolog: Optional[str] = None
         self._qmp_set = True   # Enable QMP monitor by default.
         self._qmp_connection: Optional[qmp.QEMUMonitorProtocol] = None
         self._qemu_full_args: Tuple[str, ...] = ()
-        self._temp_dir = None
+        self._temp_dir: Optional[str] = None
         self._launched = False
-        self._machine = None
+        self._machine: Optional[str] = None
         self._console_index = 0
         self._console_set = False
-        self._console_device_type = None
+        self._console_device_type: Optional[str] = None
         self._console_address = os.path.join(
             self._sock_dir, f"{self._name}-console.sock"
         )
-        self._console_socket = None
-        self._remove_files = []
+        self._console_socket: Optional[socket.socket] = None
+        self._remove_files: List[str] = []
         self._user_killed = False
 
-    def __enter__(self):
+    def __enter__(self) -> 'QEMUMachine':
         return self
 
     def __exit__(self,
@@ -159,14 +163,15 @@ class QEMUMachine:
                  exc_tb: Optional[TracebackType]) -> None:
         self.shutdown()
 
-    def add_monitor_null(self):
+    def add_monitor_null(self) -> None:
         """
         This can be used to add an unused monitor instance.
         """
         self._args.append('-monitor')
         self._args.append('null')
 
-    def add_fd(self, fd, fdset, opaque, opts=''):
+    def add_fd(self, fd: int, fdset: int,
+               opaque: str, opts: str = '') -> 'QEMUMachine':
         """
         Pass a file descriptor to the VM
         """
@@ -185,7 +190,8 @@ class QEMUMachine:
         self._args.append(','.join(options))
         return self
 
-    def send_fd_scm(self, fd=None, file_path=None):
+    def send_fd_scm(self, fd: Optional[int] = None,
+                    file_path: Optional[str] = None) -> int:
         """
         Send an fd or file_path to socket_scm_helper.
 
@@ -229,7 +235,7 @@ class QEMUMachine:
         return proc.returncode
 
     @staticmethod
-    def _remove_if_exists(path):
+    def _remove_if_exists(path: str) -> None:
         """
         Remove file object at path if it exists
         """
@@ -240,7 +246,7 @@ class QEMUMachine:
                 return
             raise
 
-    def is_running(self):
+    def is_running(self) -> bool:
         """Returns true if the VM is running."""
         return self._popen is not None and self._popen.poll() is None
 
@@ -250,19 +256,19 @@ class QEMUMachine:
             raise QEMUMachineError('Subprocess pipe not present')
         return self._popen
 
-    def exitcode(self):
+    def exitcode(self) -> Optional[int]:
         """Returns the exit code if possible, or None."""
         if self._popen is None:
             return None
         return self._popen.poll()
 
-    def get_pid(self):
+    def get_pid(self) -> Optional[int]:
         """Returns the PID of the running process, or None."""
         if not self.is_running():
             return None
         return self._subp.pid
 
-    def _load_io_log(self):
+    def _load_io_log(self) -> None:
         if self._qemu_log_path is not None:
             with open(self._qemu_log_path, "r") as iolog:
                 self._iolog = iolog.read()
@@ -296,7 +302,7 @@ class QEMUMachine:
                 args.extend(['-device', device])
         return args
 
-    def _pre_launch(self):
+    def _pre_launch(self) -> None:
         self._temp_dir = tempfile.mkdtemp(dir=self._test_dir)
         self._qemu_log_path = os.path.join(self._temp_dir, self._name + ".log")
         self._qemu_log_file = open(self._qemu_log_path, 'wb')
@@ -314,11 +320,11 @@ class QEMUMachine:
                 nickname=self._name
             )
 
-    def _post_launch(self):
+    def _post_launch(self) -> None:
         if self._qmp_connection:
             self._qmp.accept()
 
-    def _post_shutdown(self):
+    def _post_shutdown(self) -> None:
         """
         Called to cleanup the VM instance after the process has exited.
         May also be called after a failed launch.
@@ -358,7 +364,7 @@ class QEMUMachine:
         self._user_killed = False
         self._launched = False
 
-    def launch(self):
+    def launch(self) -> None:
         """
         Launch the VM and make sure we cleanup and expose the
         command line/output in case of exception
@@ -382,7 +388,7 @@ class QEMUMachine:
                 LOG.debug('Output: %r', self._iolog)
             raise
 
-    def _launch(self):
+    def _launch(self) -> None:
         """
         Launch the VM and establish a QMP connection
         """
@@ -501,7 +507,7 @@ class QEMUMachine:
         finally:
             self._post_shutdown()
 
-    def kill(self):
+    def kill(self) -> None:
         """
         Terminate the VM forcefully, wait for it to exit, and perform cleanup.
         """
@@ -516,7 +522,7 @@ class QEMUMachine:
         """
         self.shutdown(has_quit=True, timeout=timeout)
 
-    def set_qmp_monitor(self, enabled=True):
+    def set_qmp_monitor(self, enabled: bool = True) -> None:
         """
         Set the QMP monitor.
 
@@ -552,7 +558,9 @@ class QEMUMachine:
         qmp_args = self._qmp_args(conv_keys, **args)
         return self._qmp.cmd(cmd, args=qmp_args)
 
-    def command(self, cmd, conv_keys=True, **args):
+    def command(self, cmd: str,
+                conv_keys: bool = True,
+                **args: Any) -> QMPReturnValue:
         """
         Invoke a QMP command.
         On success return the response dict.
@@ -561,7 +569,7 @@ class QEMUMachine:
         qmp_args = self._qmp_args(conv_keys, **args)
         return self._qmp.command(cmd, **qmp_args)
 
-    def get_qmp_event(self, wait=False):
+    def get_qmp_event(self, wait: bool = False) -> Optional[QMPMessage]:
         """
         Poll for one queued QMP events and return it
         """
@@ -569,7 +577,7 @@ class QEMUMachine:
             return self._events.pop(0)
         return self._qmp.pull_event(wait=wait)
 
-    def get_qmp_events(self, wait=False):
+    def get_qmp_events(self, wait: bool = False) -> List[QMPMessage]:
         """
         Poll for queued QMP events and return a list of dicts
         """
@@ -580,7 +588,7 @@ class QEMUMachine:
         return events
 
     @staticmethod
-    def event_match(event, match=None):
+    def event_match(event: Any, match: Optional[Any]) -> bool:
         """
         Check if an event matches optional match criteria.
 
@@ -610,9 +618,11 @@ class QEMUMachine:
             return True
         except TypeError:
             # either match or event wasn't iterable (not a dict)
-            return match == event
+            return bool(match == event)
 
-    def event_wait(self, name, timeout=60.0, match=None):
+    def event_wait(self, name: str,
+                   timeout: float = 60.0,
+                   match: Optional[QMPMessage] = None) -> Optional[QMPMessage]:
         """
         event_wait waits for and returns a named event from QMP with a timeout.
 
@@ -622,7 +632,9 @@ class QEMUMachine:
         """
         return self.events_wait([(name, match)], timeout)
 
-    def events_wait(self, events, timeout=60.0):
+    def events_wait(self,
+                    events: Sequence[Tuple[str, Any]],
+                    timeout: float = 60.0) -> Optional[QMPMessage]:
         """
         events_wait waits for and returns a single named event from QMP.
         In the case of multiple qualifying events, this function returns the
@@ -639,7 +651,7 @@ class QEMUMachine:
         :return: A QMP event matching the filter criteria.
                  If timeout was 0 and no event matched, None.
         """
-        def _match(event):
+        def _match(event: QMPMessage) -> bool:
             for name, match in events:
                 if event['event'] == name and self.event_match(event, match):
                     return True
@@ -666,20 +678,20 @@ class QEMUMachine:
 
         return None
 
-    def get_log(self):
+    def get_log(self) -> Optional[str]:
         """
         After self.shutdown or failed qemu execution, this returns the output
         of the qemu process.
         """
         return self._iolog
 
-    def add_args(self, *args):
+    def add_args(self, *args: str) -> None:
         """
         Adds to the list of extra arguments to be given to the QEMU binary
         """
         self._args.extend(args)
 
-    def set_machine(self, machine_type):
+    def set_machine(self, machine_type: str) -> None:
         """
         Sets the machine type
 
@@ -688,7 +700,9 @@ class QEMUMachine:
         """
         self._machine = machine_type
 
-    def set_console(self, device_type=None, console_index=0):
+    def set_console(self,
+                    device_type: Optional[str] = None,
+                    console_index: int = 0) -> None:
         """
         Sets the device type for a console device
 
@@ -719,7 +733,7 @@ class QEMUMachine:
         self._console_index = console_index
 
     @property
-    def console_socket(self):
+    def console_socket(self) -> socket.socket:
         """
         Returns a socket connected to the console
         """
diff --git a/python/qemu/qmp.py b/python/qemu/qmp.py
index ddf8347ac1..9223307ed8 100644
--- a/python/qemu/qmp.py
+++ b/python/qemu/qmp.py
@@ -15,6 +15,7 @@ from types import TracebackType
 from typing import (
     Any,
     Dict,
+    List,
     Optional,
     TextIO,
     Tuple,
@@ -90,7 +91,9 @@ class QEMUMonitorProtocol:
     #: Logger object for debugging messages
     logger = logging.getLogger('QMP')
 
-    def __init__(self, address, server=False, nickname=None):
+    def __init__(self, address: SocketAddrT,
+                 server: bool = False,
+                 nickname: Optional[str] = None):
         """
         Create a QEMUMonitorProtocol class.
 
@@ -102,7 +105,7 @@ class QEMUMonitorProtocol:
         @note No connection is established, this is done by the connect() or
               accept() methods
         """
-        self.__events = []
+        self.__events: List[QMPMessage] = []
         self.__address = address
         self.__sock = self.__get_sock()
         self.__sockfile: Optional[TextIO] = None
@@ -114,14 +117,14 @@ class QEMUMonitorProtocol:
             self.__sock.bind(self.__address)
             self.__sock.listen(1)
 
-    def __get_sock(self):
+    def __get_sock(self) -> socket.socket:
         if isinstance(self.__address, tuple):
             family = socket.AF_INET
         else:
             family = socket.AF_UNIX
         return socket.socket(family, socket.SOCK_STREAM)
 
-    def __negotiate_capabilities(self):
+    def __negotiate_capabilities(self) -> QMPMessage:
         greeting = self.__json_read()
         if greeting is None or "QMP" not in greeting:
             raise QMPConnectError
@@ -131,7 +134,7 @@ class QEMUMonitorProtocol:
             return greeting
         raise QMPCapabilitiesError
 
-    def __json_read(self, only_event=False):
+    def __json_read(self, only_event: bool = False) -> Optional[QMPMessage]:
         assert self.__sockfile is not None
         while True:
             data = self.__sockfile.readline()
@@ -148,7 +151,7 @@ class QEMUMonitorProtocol:
                     continue
             return resp
 
-    def __get_events(self, wait=False):
+    def __get_events(self, wait: Union[bool, float] = False) -> None:
         """
         Check for new events in the stream and cache them in __events.
 
@@ -186,7 +189,7 @@ class QEMUMonitorProtocol:
                 raise QMPConnectError("Error while reading from socket")
             self.__sock.settimeout(None)
 
-    def __enter__(self):
+    def __enter__(self) -> 'QEMUMonitorProtocol':
         # Implement context manager enter function.
         return self
 
@@ -199,7 +202,7 @@ class QEMUMonitorProtocol:
         # Implement context manager exit function.
         self.close()
 
-    def connect(self, negotiate=True):
+    def connect(self, negotiate: bool = True) -> Optional[QMPMessage]:
         """
         Connect to the QMP Monitor and perform capabilities negotiation.
 
@@ -214,7 +217,7 @@ class QEMUMonitorProtocol:
             return self.__negotiate_capabilities()
         return None
 
-    def accept(self, timeout=15.0):
+    def accept(self, timeout: float = 15.0) -> QMPMessage:
         """
         Await connection from QMP Monitor and perform capabilities negotiation.
 
@@ -250,7 +253,9 @@ class QEMUMonitorProtocol:
         self.logger.debug("<<< %s", resp)
         return resp
 
-    def cmd(self, name, args=None, cmd_id=None):
+    def cmd(self, name: str,
+            args: Optional[Dict[str, Any]] = None,
+            cmd_id: Optional[Any] = None) -> QMPMessage:
         """
         Build a QMP command and send it to the QMP Monitor.
 
@@ -258,14 +263,14 @@ class QEMUMonitorProtocol:
         @param args: command arguments (dict)
         @param cmd_id: command id (dict, list, string or int)
         """
-        qmp_cmd = {'execute': name}
+        qmp_cmd: QMPMessage = {'execute': name}
         if args:
             qmp_cmd['arguments'] = args
         if cmd_id:
             qmp_cmd['id'] = cmd_id
         return self.cmd_obj(qmp_cmd)
 
-    def command(self, cmd, **kwds):
+    def command(self, cmd: str, **kwds: Any) -> QMPReturnValue:
         """
         Build and send a QMP command to the monitor, report errors if any
         """
@@ -278,7 +283,8 @@ class QEMUMonitorProtocol:
             )
         return cast(QMPReturnValue, ret['return'])
 
-    def pull_event(self, wait=False):
+    def pull_event(self,
+                   wait: Union[bool, float] = False) -> Optional[QMPMessage]:
         """
         Pulls a single event.
 
@@ -298,7 +304,7 @@ class QEMUMonitorProtocol:
             return self.__events.pop(0)
         return None
 
-    def get_events(self, wait=False):
+    def get_events(self, wait: bool = False) -> List[QMPMessage]:
         """
         Get a list of available QMP events.
 
@@ -315,13 +321,13 @@ class QEMUMonitorProtocol:
         self.__get_events(wait)
         return self.__events
 
-    def clear_events(self):
+    def clear_events(self) -> None:
         """
         Clear current list of pending events.
         """
         self.__events = []
 
-    def close(self):
+    def close(self) -> None:
         """
         Close the socket and socket file.
         """
@@ -330,7 +336,7 @@ class QEMUMonitorProtocol:
         if self.__sockfile:
             self.__sockfile.close()
 
-    def settimeout(self, timeout):
+    def settimeout(self, timeout: float) -> None:
         """
         Set the socket timeout.
 
@@ -339,7 +345,7 @@ class QEMUMonitorProtocol:
         """
         self.__sock.settimeout(timeout)
 
-    def get_sock_fd(self):
+    def get_sock_fd(self) -> int:
         """
         Get the socket file descriptor.
 
@@ -347,7 +353,7 @@ class QEMUMonitorProtocol:
         """
         return self.__sock.fileno()
 
-    def is_scm_available(self):
+    def is_scm_available(self) -> bool:
         """
         Check if the socket allows for SCM_RIGHTS.
 
diff --git a/python/qemu/qtest.py b/python/qemu/qtest.py
index 675310d8df..39a0cf62fe 100644
--- a/python/qemu/qtest.py
+++ b/python/qemu/qtest.py
@@ -27,6 +27,7 @@ from typing import (
 )
 
 from .machine import QEMUMachine
+from .qmp import SocketAddrT
 
 
 class QEMUQtestProtocol:
@@ -43,7 +44,8 @@ class QEMUQtestProtocol:
        No conection is estabalished by __init__(), this is done
        by the connect() or accept() methods.
     """
-    def __init__(self, address, server=False):
+    def __init__(self, address: SocketAddrT,
+                 server: bool = False):
         self._address = address
         self._sock = self._get_sock()
         self._sockfile: Optional[TextIO] = None
@@ -51,14 +53,14 @@ class QEMUQtestProtocol:
             self._sock.bind(self._address)
             self._sock.listen(1)
 
-    def _get_sock(self):
+    def _get_sock(self) -> socket.socket:
         if isinstance(self._address, tuple):
             family = socket.AF_INET
         else:
             family = socket.AF_UNIX
         return socket.socket(family, socket.SOCK_STREAM)
 
-    def connect(self):
+    def connect(self) -> None:
         """
         Connect to the qtest socket.
 
@@ -67,7 +69,7 @@ class QEMUQtestProtocol:
         self._sock.connect(self._address)
         self._sockfile = self._sock.makefile(mode='r')
 
-    def accept(self):
+    def accept(self) -> None:
         """
         Await connection from QEMU.
 
@@ -76,7 +78,7 @@ class QEMUQtestProtocol:
         self._sock, _ = self._sock.accept()
         self._sockfile = self._sock.makefile(mode='r')
 
-    def cmd(self, qtest_cmd):
+    def cmd(self, qtest_cmd: str) -> str:
         """
         Send a qtest command on the wire.
 
@@ -87,14 +89,16 @@ class QEMUQtestProtocol:
         resp = self._sockfile.readline()
         return resp
 
-    def close(self):
-        """Close this socket."""
+    def close(self) -> None:
+        """
+        Close this socket.
+        """
         self._sock.close()
         if self._sockfile:
             self._sockfile.close()
             self._sockfile = None
 
-    def settimeout(self, timeout):
+    def settimeout(self, timeout: Optional[float]) -> None:
         """Set a timeout, in seconds."""
         self._sock.settimeout(timeout)
 
@@ -118,7 +122,7 @@ class QEMUQtestMachine(QEMUMachine):
         super().__init__(binary, args, name=name, test_dir=test_dir,
                          socket_scm_helper=socket_scm_helper,
                          sock_dir=sock_dir)
-        self._qtest = None
+        self._qtest: Optional[QEMUQtestProtocol] = None
         self._qtest_path = os.path.join(sock_dir, name + "-qtest.sock")
 
     @property
@@ -130,7 +134,7 @@ class QEMUQtestMachine(QEMUMachine):
         ])
         return args
 
-    def _pre_launch(self):
+    def _pre_launch(self) -> None:
         super()._pre_launch()
         self._qtest = QEMUQtestProtocol(self._qtest_path, server=True)
 
@@ -139,7 +143,7 @@ class QEMUQtestMachine(QEMUMachine):
         super()._post_launch()
         self._qtest.accept()
 
-    def _post_shutdown(self):
+    def _post_shutdown(self) -> None:
         super()._post_shutdown()
         self._remove_if_exists(self._qtest_path)