python/qemu: make 'args' style arguments immutable

These arguments don't need to be mutable and aren't really used as
such. Clarify their types as immutable and adjust code to match where
necessary.

In general, It's probably best not to accept a user-defined mutable
object and store it as internal object state unless there's a strong
justification for doing so. Instead, try to use generic types as input
with empty tuples as the default, and coerce to list where necessary.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20201006235817.3280413-10-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
This commit is contained in:
John Snow 2020-10-06 19:58:06 -04:00
parent 9223fda464
commit aad3f3bb6c
2 changed files with 34 additions and 18 deletions

View File

@ -18,6 +18,7 @@ which provides facilities for managing the lifetime of a QEMU VM.
#
import errno
from itertools import chain
import logging
import os
import shutil
@ -30,6 +31,8 @@ from typing import (
Dict,
List,
Optional,
Sequence,
Tuple,
Type,
)
@ -74,8 +77,12 @@ class QEMUMachine:
# vm is guaranteed to be shut down here
"""
def __init__(self, binary, args=None, wrapper=None, name=None,
test_dir="/var/tmp",
def __init__(self,
binary: str,
args: Sequence[str] = (),
wrapper: Sequence[str] = (),
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):
@ -97,14 +104,7 @@ class QEMUMachine:
# Direct user configuration
self._binary = binary
if args is None:
args = []
# Copy mutable input: we will be modifying our copy
self._args = list(args)
if wrapper is None:
wrapper = []
self._wrapper = wrapper
self._name = name or "qemu-%d" % os.getpid()
@ -136,7 +136,7 @@ class QEMUMachine:
self._iolog = None
self._qmp_set = True # Enable QMP monitor by default.
self._qmp_connection: Optional[qmp.QEMUMonitorProtocol] = None
self._qemu_full_args = None
self._qemu_full_args: Tuple[str, ...] = ()
self._temp_dir = None
self._launched = False
self._machine = None
@ -368,7 +368,7 @@ class QEMUMachine:
raise QEMUMachineError('VM already launched')
self._iolog = None
self._qemu_full_args = None
self._qemu_full_args = ()
try:
self._launch()
self._launched = True
@ -388,8 +388,12 @@ class QEMUMachine:
"""
devnull = open(os.path.devnull, 'rb')
self._pre_launch()
self._qemu_full_args = (self._wrapper + [self._binary] +
self._base_args + self._args)
self._qemu_full_args = tuple(
chain(self._wrapper,
[self._binary],
self._base_args,
self._args)
)
LOG.debug('VM launch command: %r', ' '.join(self._qemu_full_args))
self._popen = subprocess.Popen(self._qemu_full_args,
stdin=devnull,

View File

@ -19,7 +19,12 @@ subclass of QEMUMachine, respectively.
import os
import socket
from typing import List, Optional, TextIO
from typing import (
List,
Optional,
Sequence,
TextIO,
)
from .machine import QEMUMachine
@ -99,8 +104,13 @@ class QEMUQtestMachine(QEMUMachine):
A QEMU VM, with a qtest socket available.
"""
def __init__(self, binary, args=None, name=None, test_dir="/var/tmp",
socket_scm_helper=None, sock_dir=None):
def __init__(self,
binary: str,
args: Sequence[str] = (),
name: Optional[str] = None,
test_dir: str = "/var/tmp",
socket_scm_helper: Optional[str] = None,
sock_dir: Optional[str] = None):
if name is None:
name = "qemu-%d" % os.getpid()
if sock_dir is None:
@ -114,8 +124,10 @@ class QEMUQtestMachine(QEMUMachine):
@property
def _base_args(self) -> List[str]:
args = super()._base_args
args.extend(['-qtest', 'unix:path=' + self._qtest_path,
'-accel', 'qtest'])
args.extend([
'-qtest', f"unix:path={self._qtest_path}",
'-accel', 'qtest'
])
return args
def _pre_launch(self):