Commit d792bc38 authored by Stefan Hajnoczi's avatar Stefan Hajnoczi
Browse files

qemu.py: make VM() a context manager 



There are a number of ways to ensure that the QEMU process is shut down
when the test ends, including atexit.register(), try: finally:, or
unittest.teardown() methods.  All of these require extra code and the
programmer must remember to add vm.shutdown().

A nice solution is context managers:

  with VM(binary) as vm:
      ...
  # vm is guaranteed to be shut down here

Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarEduardo Habkost <ehabkost@redhat.com>
Message-id: 20170824072202.26818-2-stefanha@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 2b483739

scripts/qemu.py

+15 −1
Original line number Diff line number Diff line
@@ -21,7 +21,14 @@ import qmp.qmp 




class QEMUMachine(object):

    '''A QEMU VM'''

    '''A QEMU VM



    Use this object as a context manager to ensure the QEMU process terminates::



        with VM(binary) as vm:

            ...

        # vm is guaranteed to be shut down here

    '''



    def __init__(self, binary, args=[], wrapper=[], name=None, test_dir="/var/tmp",

                 monitor_address=None, socket_scm_helper=None, debug=False):
@@ -40,6 +47,13 @@ class QEMUMachine(object): 
        self._socket_scm_helper = socket_scm_helper

        self._debug = debug



    def __enter__(self):

        return self



    def __exit__(self, exc_type, exc_val, exc_tb):

        self.shutdown()

        return False



    # This can be used to add an unused monitor instance.

    def add_monitor_telnet(self, ip, port):

        args = 'tcp:%s:%d,server,nowait,telnet' % (ip, port)