Re: [PATCH 07/20] python/machine.py: Add _qmp access shim

2020-10-07 Thread John Snow 

On 10/7/20 5:53 AM, Kevin Wolf wrote:

Am 07.10.2020 um 01:58 hat John Snow geschrieben:

Like many other Optional[] types, it's not always a given that this
object will be set. Wrap it in a type-shim that raises a meaningful
error and will always return a concrete type.

Signed-off-by: John Snow 



@@ -515,11 +515,13 @@ def set_qmp_monitor(self, enabled=True):
  line. Default is True.
  @note: call this function before launch().
  """
-if enabled:
-self._qmp_set = True
-else:
-self._qmp_set = False
-self._qmp = None
+self._qmp_set = enabled


This change seems unrelated to wrapping the connection in a property.
Intuitively, it makes sense that the connection of a running instance
doesn't go away just because I disable QMP in the command line for the
next launch.

If this is the reasoning behind the change, maybe mention it in the
commit message.

With this:
Reviewed-by: Kevin Wolf 



Oh, yes. That's what happened here -- and it got folded in here 
specifically to make that access check consistent.


I'll update the commit message.

Re: [PATCH 07/20] python/machine.py: Add _qmp access shim

2020-10-07 Thread Kevin Wolf 
Am 07.10.2020 um 01:58 hat John Snow geschrieben:
> Like many other Optional[] types, it's not always a given that this
> object will be set. Wrap it in a type-shim that raises a meaningful
> error and will always return a concrete type.
> 
> Signed-off-by: John Snow 

> @@ -515,11 +515,13 @@ def set_qmp_monitor(self, enabled=True):
>  line. Default is True.
>  @note: call this function before launch().
>  """
> -if enabled:
> -self._qmp_set = True
> -else:
> -self._qmp_set = False
> -self._qmp = None
> +self._qmp_set = enabled

This change seems unrelated to wrapping the connection in a property.
Intuitively, it makes sense that the connection of a running instance
doesn't go away just because I disable QMP in the command line for the
next launch.

If this is the reasoning behind the change, maybe mention it in the
commit message.

With this:
Reviewed-by: Kevin Wolf

[PATCH 07/20] python/machine.py: Add _qmp access shim

2020-10-06 Thread John Snow 
Like many other Optional[] types, it's not always a given that this
object will be set. Wrap it in a type-shim that raises a meaningful
error and will always return a concrete type.

Signed-off-by: John Snow 
---
 python/qemu/machine.py | 24 +---
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/python/qemu/machine.py b/python/qemu/machine.py
index d788e8aba8c..3e9cf09fd2d 100644
--- a/python/qemu/machine.py
+++ b/python/qemu/machine.py
@@ -135,7 +135,7 @@ def __init__(self, binary, args=None, wrapper=None, 
name=None,
 self._events = []
 self._iolog = None
 self._qmp_set = True   # Enable QMP monitor by default.
-self._qmp = None
+self._qmp_connection: Optional[qmp.QEMUMonitorProtocol] = None
 self._qemu_full_args = None
 self._temp_dir = None
 self._launched = False
@@ -302,14 +302,14 @@ def _pre_launch(self):
 if self._remove_monitor_sockfile:
 assert isinstance(self._monitor_address, str)
 self._remove_files.append(self._monitor_address)
-self._qmp = qmp.QEMUMonitorProtocol(
+self._qmp_connection = qmp.QEMUMonitorProtocol(
 self._monitor_address,
 server=True,
 nickname=self._name
 )
 
 def _post_launch(self):
-if self._qmp:
+if self._qmp_connection:
 self._qmp.accept()
 
 def _post_shutdown(self):
@@ -320,9 +320,9 @@ def _post_shutdown(self):
 # Comprehensive reset for the failed launch case:
 self._early_cleanup()
 
-if self._qmp:
+if self._qmp_connection:
 self._qmp.close()
-self._qmp = None
+self._qmp_connection = None
 
 self._load_io_log()
 
@@ -434,7 +434,7 @@ def _soft_shutdown(self, timeout: Optional[int],
 """
 self._early_cleanup()
 
-if self._qmp is not None:
+if self._qmp_connection:
 if not has_quit:
 # Might raise ConnectionReset
 self._qmp.cmd('quit')
@@ -515,11 +515,13 @@ def set_qmp_monitor(self, enabled=True):
 line. Default is True.
 @note: call this function before launch().
 """
-if enabled:
-self._qmp_set = True
-else:
-self._qmp_set = False
-self._qmp = None
+self._qmp_set = enabled
+
+@property
+def _qmp(self) -> qmp.QEMUMonitorProtocol:
+if self._qmp_connection is None:
+raise QEMUMachineError("Attempt to access QMP with no connection")
+return self._qmp_connection
 
 @classmethod
 def _qmp_args(cls, _conv_keys: bool = True, **args: Any) -> Dict[str, Any]:
-- 
2.26.2