python: create qemu packages

move python/qemu/*.py to python/qemu/[machine, qmp, utils]/*.py and
update import directives across the tree.

This is done to create a PEP420 namespace package, in which we may
create subpackages. To do this, the namespace directory ("qemu") should
not have any modules in it. Those files will go into new 'machine',
'qmp' and 'utils' subpackages instead.

Implement machine/__init__.py making the top-level classes and functions
from its various modules available directly inside the package. Change
qmp.py to qmp/__init__.py similarly, such that all of the useful QMP
library classes are available directly from "qemu.qmp" instead of
"qemu.qmp.qmp".

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Message-id: 20210527211715.394144-10-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>

python/qemu/__init__.py

@@ -1,11 +0,0 @@
-# QEMU library
-#
-# Copyright (C) 2015-2016 Red Hat Inc.
-# Copyright (C) 2012 IBM Corp.
-#
-# Authors:
-#  Fam Zheng <famz@redhat.com>
-#
-# This work is licensed under the terms of the GNU GPL, version 2.  See
-# the COPYING file in the top-level directory.
-#

python/qemu/machine/__init__.py

@@ -0,0 +1,33 @@
+"""
+QEMU development and testing library.
+
+This library provides a few high-level classes for driving QEMU from a
+test suite, not intended for production use.
+
+- QEMUMachine: Configure and Boot a QEMU VM
+ - QEMUQtestMachine: VM class, with a qtest socket.
+
+- QEMUQtestProtocol: Connect to, send/receive qtest messages.
+"""
+
+# Copyright (C) 2020-2021 John Snow for Red Hat Inc.
+# Copyright (C) 2015-2016 Red Hat Inc.
+# Copyright (C) 2012 IBM Corp.
+#
+# Authors:
+#  John Snow <jsnow@redhat.com>
+#  Fam Zheng <fam@euphon.net>
+#
+# This work is licensed under the terms of the GNU GPL, version 2.  See
+# the COPYING file in the top-level directory.
+#
+
+from .machine import QEMUMachine
+from .qtest import QEMUQtestMachine, QEMUQtestProtocol
+
+
+__all__ = (
+    'QEMUMachine',
+    'QEMUQtestProtocol',
+    'QEMUQtestMachine',
+)

python/qemu/machine/machine.py

@@ -38,8 +38,14 @@ from typing import (
     Type,
 )
 
-from . import console_socket, qmp
-from .qmp import QMPMessage, QMPReturnValue, SocketAddrT
+from qemu.qmp import (
+    QEMUMonitorProtocol,
+    QMPMessage,
+    QMPReturnValue,
+    SocketAddrT,
+)
+
+from . import console_socket
 
 
 LOG = logging.getLogger(__name__)
@@ -139,7 +145,7 @@ class QEMUMachine:
         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._qmp_connection: Optional[QEMUMonitorProtocol] = None
         self._qemu_full_args: Tuple[str, ...] = ()
         self._temp_dir: Optional[str] = None
         self._launched = False
@@ -314,7 +320,7 @@ class QEMUMachine:
             if self._remove_monitor_sockfile:
                 assert isinstance(self._monitor_address, str)
                 self._remove_files.append(self._monitor_address)
-            self._qmp_connection = qmp.QEMUMonitorProtocol(
+            self._qmp_connection = QEMUMonitorProtocol(
                 self._monitor_address,
                 server=True,
                 nickname=self._name
@@ -541,7 +547,7 @@ class QEMUMachine:
         self._qmp_set = enabled
 
     @property
-    def _qmp(self) -> qmp.QEMUMonitorProtocol:
+    def _qmp(self) -> QEMUMonitorProtocol:
         if self._qmp_connection is None:
             raise QEMUMachineError("Attempt to access QMP with no connection")
         return self._qmp_connection

python/qemu/machine/qtest.py

@@ -26,8 +26,9 @@ from typing import (
     TextIO,
 )
 
+from qemu.qmp import SocketAddrT
+
 from .machine import QEMUMachine
-from .qmp import SocketAddrT
 
 
 class QEMUQtestProtocol:

python/qemu/qmp/__init__.py

@@ -1,4 +1,14 @@
-""" QEMU Monitor Protocol Python class """
+"""
+QEMU Monitor Protocol (QMP) development library & tooling.
+
+This package provides a fairly low-level class for communicating to QMP
+protocol servers, as implemented by QEMU, the QEMU Guest Agent, and the
+QEMU Storage Daemon. This library is not intended for production use.
+
+`QEMUMonitorProtocol` is the primary class of interest, and all errors
+raised derive from `QMPError`.
+"""
+
 # Copyright (C) 2009, 2010 Red Hat Inc.
 #
 # Authors:

python/qemu/utils/__init__.py

@@ -1,13 +1,14 @@
 """
-QEMU utility library
+QEMU development and testing utilities
 
-This offers miscellaneous utility functions, which may not be easily
-distinguishable or numerous to be in their own module.
+This package provides a small handful of utilities for performing
+various tasks not directly related to the launching of a VM.
 """
 
 # Copyright (C) 2021 Red Hat Inc.
 #
 # Authors:
+#  John Snow <jsnow@redhat.com>
 #  Cleber Rosa <crosa@redhat.com>
 #
 # This work is licensed under the terms of the GNU GPL, version 2.  See
@@ -17,6 +18,17 @@ distinguishable or numerous to be in their own module.
 import re
 from typing import Optional
 
+# pylint: disable=import-error
+from .accel import kvm_available, list_accel, tcg_available
+
+
+__all__ = (
+    'get_info_usernet_hostfwd_port',
+    'kvm_available',
+    'list_accel',
+    'tcg_available',
+)
+
 
 def get_info_usernet_hostfwd_port(info_usernet_output: str) -> Optional[int]:
     """