Added context manager capability to WBEMSubscriptionManager; correcte…

…d DSP1054 references in its docs.

docs/changes.rst

@@ -48,6 +48,10 @@ Enhancements
   response processing and indication processing  This is a significant reduction
   in memory usage. See issue # 498.
 
+* Added enter and exit methods to `WBEMSubscriptionManager` to enable using it
+  as a context manager, whose exit method automatically cleans up by calling
+  `remove_all_servers()`.
+
 
 Bug fixes
 ^^^^^^^^^

pywbem/_subscription_manager.py

@@ -138,6 +138,13 @@ def main():
 
         subscription_manager.add_subscription(server2_id, filter2_path)
 
+The following example code briefly shows how to use a subscription manager
+as a context manager, in order to get automatic cleanup::
+
+    with WBEMSubscriptionManager('fred') as subscription_manager:
+        server1_id = subscription_manager.add_server(server1)
+    # exit method automatically calls remove_all_servers()
+
 Another more practical example is in the script
 ``examples/pegIndicationTest.py`` (when you clone the GitHub pywbem/pywbem
 project).
@@ -169,6 +176,9 @@ class WBEMSubscriptionManager(object):
     """
     A class for managing subscriptions for CIM indications in a WBEM server.
 
+    The class may be used as a context manager, whose
+    :meth:`~pywbem.WBEMSubscriptionManager.__exit__` method will automatically
+    clean up.
     """
 
     def __init__(self, subscription_manager_id=None):
@@ -226,6 +236,22 @@ def __repr__(self):
                 self._servers, self._owned_subscription_paths,
                 self._owned_filter_paths, self._owned_destination_paths)
 
+    def __enter__(self):
+        """
+        Enter method when the class is used as a context manager.
+        """
+        pass
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        """
+        Exit method when the class is used as a context manager.
+
+        It cleans up by calling
+        :meth:`~pywbem.WBEMSubscriptionManager.remove_all_servers`.
+        """
+        self.remove_all_servers()
+        return False  # re-raise any exceptions
+
     def _get_server(self, server_id):
         """
             Internal method to get the server object given a server_id.
@@ -546,7 +572,7 @@ def remove_destinations(self, server_id, destination_paths):
         This method verifies that there are not currently any subscriptions on
         the specified listener destination, in order to handle server
         implementations that do not ensure that on the server side as required
-        by :ref:`DSP1054`.
+        by :term:`DSP1054`.
 
         Parameters:
 
@@ -763,7 +789,7 @@ def remove_filter(self, server_id, filter_path):
         This method verifies that there are not currently any subscriptions on
         the specified indication filter, in order to handle server
         implementations that do not ensure that on the server side as required
-        by :ref:`DSP1054`.
+        by :term:`DSP1054`.
 
         Parameters:
 

testsuite/run_cim_operations.py

@@ -3652,6 +3652,37 @@ def test_both_indications(self):
 
             my_listener.stop()
 
+    def test_subscription_context_manager(self):
+        """Test that the WBEMSUbscriptionmanager class can be used as a
+           Python context manager and that its exit method cleans up.
+        """
+
+        if self.is_pegasus_test_build():
+
+            server = WBEMServer(self.conn)
+
+            # First, verify the behavior of remove_all_servers() with a
+            # normal WBEMSubscriptionManager instance.
+
+            sub_mgr = WBEMSubscriptionManager(
+                subscription_manager_id='test_ctxt_mgr_1')
+
+            server_id = sub_mgr.add_server(server)
+            self.assertEqual(set(sub_mgr._servers.keys()), {server_id})
+
+            sub_mgr.remove_all_servers()
+            self.assertEqual(set(sub_mgr._servers.keys()), {})
+
+            # Now, perform the actual test of the context manager.
+
+            with WBEMSubscriptionManager(
+                    subscription_manager_id='test_ctxt_mgr_2') as sub_mgr:
+
+                server_id = sub_mgr.add_server(server)
+                self.assertEqual(set(sub_mgr._servers.keys()), {server_id})
+
+            self.assertEqual(set(sub_mgr._servers.keys()), {})
+
 
 #################################################################
 # Main function