Session management and Event handling

[sadim]

Hello,

I have questions about the session management and the event handling.
I write a simple application to control vm machines. I found two ways to get an session

(oVBoxMgr is an instance of VirtualBoxManager)
oVBoxMgr.openMachineSession(mach, True) and oVBoxMgr.getSessionObject(vbox)

Both functions give me a session but what are the differences?

The following things i have found out:

• openMachineSession(mach, True)
  - Locks the machine
  - need closeMachineSession(session) at the end (unlock the machine and...?)

• getSessionObject(vbox)
  - doesn't locks the machine
  - need lockMachine to locks the machine
  - need session.unlockMachine() at the end to unlock the machine

Is that correct? Why are there these two possibilities? Where can I find the implementation of these functions?

My second question is about the event handling.
Is there an example implementation in python for e.g. listen to an IMachineDataChangeEvent?

[noteirak]

The first method is just a convenient method but is not directly used in the SDK howto documentation, so I would guess it's an internal method that Devs use and can change at anytime.
The second method is the proper way of doing it and I would recommend to only use that one.

As for the event listening, I don't know how it would translate into Python but to get that event you need to either listen on the general Virtualbox object or on the virtualbox machine object directly.
The SDK PDF tells you how to manage this but in any case you'll need to use the getEventSource() on either IVirtualbox or IMachine objects.

[sadim]

Thanks a lot for the explanation.