Blame SOURCES/kvm-qemu.py-make-VM-a-context-manager.patch

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From da96c55a017fbc750b49550c6e7a523dcdab0dbe Mon Sep 17 00:00:00 2001
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From: Stefan Hajnoczi <stefanha@redhat.com>
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Date: Fri, 22 Dec 2017 11:08:41 +0100
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Subject: [PATCH 23/42] qemu.py: make VM() a context manager
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RH-Author: Stefan Hajnoczi <stefanha@redhat.com>
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Message-id: <20171222110900.24813-2-stefanha@redhat.com>
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Patchwork-id: 78483
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O-Subject: [RHV7.5 qemu-kvm-rhev PATCH 01/20] qemu.py: make VM() a context manager
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Bugzilla: 1519721
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Jeffrey Cody <jcody@redhat.com>
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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There are a number of ways to ensure that the QEMU process is shut down
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when the test ends, including atexit.register(), try: finally:, or
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unittest.teardown() methods.  All of these require extra code and the
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programmer must remember to add vm.shutdown().
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A nice solution is context managers:
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  with VM(binary) as vm:
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      ...
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  # vm is guaranteed to be shut down here
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Cc: Eduardo Habkost <ehabkost@redhat.com>
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
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Message-id: 20170824072202.26818-2-stefanha@redhat.com
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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(cherry picked from commit d792bc3811f22a22a46c7d9a725fd29029f54095)
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 scripts/qemu.py | 16 +++++++++++++++-
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 1 file changed, 15 insertions(+), 1 deletion(-)
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diff --git a/scripts/qemu.py b/scripts/qemu.py
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index 880e3e8..4d8ee10 100644
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--- a/scripts/qemu.py
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+++ b/scripts/qemu.py
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@@ -21,7 +21,14 @@ import qmp.qmp
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 class QEMUMachine(object):
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-    '''A QEMU VM'''
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+    '''A QEMU VM
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+
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+    Use this object as a context manager to ensure the QEMU process terminates::
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+
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+        with VM(binary) as vm:
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+            ...
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+        # vm is guaranteed to be shut down here
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+    '''
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     def __init__(self, binary, args=[], wrapper=[], name=None, test_dir="/var/tmp",
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                  monitor_address=None, socket_scm_helper=None, debug=False):
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@@ -40,6 +47,13 @@ class QEMUMachine(object):
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         self._socket_scm_helper = socket_scm_helper
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         self._debug = debug
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+    def __enter__(self):
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+        return self
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+
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+    def __exit__(self, exc_type, exc_val, exc_tb):
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+        self.shutdown()
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+        return False
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+
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     # This can be used to add an unused monitor instance.
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     def add_monitor_telnet(self, ip, port):
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         args = 'tcp:%s:%d,server,nowait,telnet' % (ip, port)
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-- 
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1.8.3.1
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