Python: expose QEMUMachine's temporary directory

Each instance of qemu.machine.QEMUMachine currently has a "test
directory", which may not have any relation to a "test", and it's
really a temporary directory.

Users instantiating the QEMUMachine class will be able to set the
location of the directory that will *contain* the QEMUMachine unique
temporary directory, so that parameter name has been changed from
test_dir to base_temp_dir.

A property has been added to allow users to access it without using
private attributes, and with that, the directory is created on first
use of the property.

Signed-off-by: Cleber Rosa <crosa@redhat.com>
Message-Id: <20210211220146.2525771-3-crosa@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Signed-off-by: Cleber Rosa <crosa@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>

python/qemu/machine.py

@@ -84,7 +84,7 @@ def __init__(self,
                  args: Sequence[str] = (),
                  wrapper: Sequence[str] = (),
                  name: Optional[str] = None,
-                 test_dir: str = "/var/tmp",
+                 base_temp_dir: str = "/var/tmp",
                  monitor_address: Optional[SocketAddrT] = None,
                  socket_scm_helper: Optional[str] = None,
                  sock_dir: Optional[str] = None,
@@ -97,10 +97,10 @@ def __init__(self,
         @param args: list of extra arguments
         @param wrapper: list of arguments used as prefix to qemu binary
         @param name: prefix for socket and log file names (default: qemu-PID)
-        @param test_dir: where to create socket and log file
+        @param base_temp_dir: default location where temporary files are created
         @param monitor_address: address for QMP monitor
         @param socket_scm_helper: helper program, required for send_fd_scm()
-        @param sock_dir: where to create socket (overrides test_dir for sock)
+        @param sock_dir: where to create socket (defaults to base_temp_dir)
         @param drain_console: (optional) True to drain console socket to buffer
         @param console_log: (optional) path to console log file
         @note: Qemu process is not started until launch() is used.
@@ -112,8 +112,8 @@ def __init__(self,
         self._wrapper = wrapper
 
         self._name = name or "qemu-%d" % os.getpid()
-        self._test_dir = test_dir
-        self._sock_dir = sock_dir or self._test_dir
+        self._base_temp_dir = base_temp_dir
+        self._sock_dir = sock_dir or self._base_temp_dir
         self._socket_scm_helper = socket_scm_helper
 
         if monitor_address is not None:
@@ -303,9 +303,7 @@ def _base_args(self) -> List[str]:
         return args
 
     def _pre_launch(self) -> None:
-        self._temp_dir = tempfile.mkdtemp(prefix="qemu-machine-",
-                                          dir=self._test_dir)
-        self._qemu_log_path = os.path.join(self._temp_dir, self._name + ".log")
+        self._qemu_log_path = os.path.join(self.temp_dir, self._name + ".log")
         self._qemu_log_file = open(self._qemu_log_path, 'wb')
 
         if self._console_set:
@@ -744,3 +742,13 @@ def console_socket(self) -> socket.socket:
                 file=self._console_log_path,
                 drain=self._drain_console)
         return self._console_socket
+
+    @property
+    def temp_dir(self) -> str:
+        """
+        Returns a temporary directory to be used for this machine
+        """
+        if self._temp_dir is None:
+            self._temp_dir = tempfile.mkdtemp(prefix="qemu-machine-",
+                                              dir=self._base_temp_dir)
+        return self._temp_dir

python/qemu/qtest.py

@@ -112,14 +112,14 @@ def __init__(self,
                  binary: str,
                  args: Sequence[str] = (),
                  name: Optional[str] = None,
-                 test_dir: str = "/var/tmp",
+                 base_temp_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:
-            sock_dir = test_dir
-        super().__init__(binary, args, name=name, test_dir=test_dir,
+            sock_dir = base_temp_dir
+        super().__init__(binary, args, name=name, base_temp_dir=base_temp_dir,
                          socket_scm_helper=socket_scm_helper,
                          sock_dir=sock_dir)
         self._qtest: Optional[QEMUQtestProtocol] = None

tests/qemu-iotests/iotests.py

@@ -571,7 +571,7 @@ class VM(qtest.QEMUQtestMachine):
     def __init__(self, path_suffix=''):
         name = "qemu%s-%d" % (path_suffix, os.getpid())
         super().__init__(qemu_prog, qemu_opts, name=name,
-                         test_dir=test_dir,
+                         base_temp_dir=test_dir,
                          socket_scm_helper=socket_scm_helper,
                          sock_dir=sock_dir)
         self._num_drives = 0