gplazma: make plugin creation caching optional

This patch introduces the gplazma.enable.plugin-creation-caching configuration property that
allows the admin to switch off the plugin cache.  This is useful as the cache is arguable a
misfeature and, in its current form, can lead to undesirable behaviour.

A subsequent patch (targeted at master only) will remove this feature.

Target: master
Patch: https://rb.dcache.org/r/7210/
Acked-by: Tigran Mkrtchyan
Request: 2.10
Request: 2.9
Request: 2.8
Request: 2.7
Request: 2.6
Require-notes: true
Require-book: no

modules/dcache-gplazma/src/main/java/org/dcache/auth/Gplazma2LoginStrategy.java

@@ -46,6 +46,7 @@ public class Gplazma2LoginStrategy
     private GPlazma _gplazma;
     private Map<String,Object> _environment = Collections.emptyMap();
     private PluginFactory _factory;
+    private boolean _shouldCachePluginCreation;
 
     @Required
     public void setConfigurationFile(String configurationFile)
@@ -66,6 +67,12 @@ public void setNameSpace(NameSpaceProvider namespace)
         _factory = new DcacheAwarePluginFactory(namespace);
     }
 
+    @Required
+    public void setCachePluginCreation(boolean cache)
+    {
+        _shouldCachePluginCreation = cache;
+    }
+
     public String getConfigurationFile()
     {
         return _configurationFile;
@@ -109,6 +116,7 @@ public void init()
             new FromFileConfigurationLoadingStrategy(_configurationFile);
         _gplazma =
             new GPlazma(configuration, getEnvironmentAsProperties(), _factory);
+        _gplazma.setCachePluginCreation(_shouldCachePluginCreation);
     }
 
     static LoginReply

modules/dcache/src/main/resources/org/dcache/services/login/gplazma.xml

@@ -50,6 +50,7 @@
   <bean id="login-strategy" class="org.dcache.auth.Gplazma2LoginStrategy" init-method="init">
     <description>Interfaces with gPlazma</description>
     <property name="configurationFile" value="${gplazma.configuration.file}"/>
+    <property name="cachePluginCreation" value="${gplazma.enable.plugin-creation-caching}"/>
     <property name="nameSpace" ref="namespace"/>
   </bean>
 </beans>

modules/gplazma2/src/main/java/org/dcache/gplazma/GPlazma.java

@@ -108,6 +108,8 @@ public boolean apply(Object o)
     private ValidationStrategy validationStrategy;
     private IdentityStrategy identityStrategy;
 
+    private boolean _shouldCachePluginCreation;
+
     /**
      * Storage class for failed login attempts.  This allows gPlazma to
      * refrain from filling up log files should a client attempt multiple
@@ -231,6 +233,11 @@ public GPlazma(ConfigurationLoadingStrategy configurationLoadingStrategy,
         }
     }
 
+    public void setCachePluginCreation(boolean shouldCache)
+    {
+        _shouldCachePluginCreation = shouldCache;
+    }
+
     public LoginReply login(Subject subject) throws AuthenticationException
     {
         RecordingLoginMonitor record = new RecordingLoginMonitor();
@@ -437,8 +444,10 @@ private void loadPlugins() throws GPlazmaInternalException
     {
         LOGGER.debug("reloading plugins");
 
-        pluginLoader = new CachingPluginLoaderDecorator(
-                XmlResourcePluginLoader.newPluginLoader());
+        pluginLoader = XmlResourcePluginLoader.newPluginLoader();
+        if (_shouldCachePluginCreation) {
+            pluginLoader = new CachingPluginLoaderDecorator(pluginLoader);
+        }
         if(_customPluginFactory != null) {
             pluginLoader.setPluginFactory(_customPluginFactory);
         }

skel/share/defaults/gplazma.properties

@@ -48,6 +48,31 @@ gplazma.configuration.file=${dcache.paths.etc}/gplazma.conf
 #  Cell address of pnfsmanager service
 gplazma.service.pnfsmanager=${dcache.service.pnfsmanager}
 
+#  Whether to cache gPlazma plugin creation.
+#
+#  Instances of those plugins mentioned in the gPlazma configuration
+#  file are created when the configuration file is read.  This
+#  property controls whether subsequent plugins with the same name
+#  will reuse the plugin instance.
+#
+#  Selecting 'true' will result in a single plugin instance for all
+#  lines in the configuration file with the same plugin name.  When a
+#  configuration file has multiple plugins with the same name, only
+#  the plugin-specific configuration (if any) of the first plugin (in
+#  document order) is honoured.  All subsequent plugin-specific
+#  configuration for plugins with the same name is ignored.
+#
+#  Selecting 'false' will result in always creating a new plugin
+#  instance.  All plugin-specific configuration is honoured.
+#
+#  The default value ('true') can lead to broken behaviour but
+#  maintains backwards-compatibility with earlier dCache releases.
+#  This property is scheduled to be removed in dCache release 2.11.0,
+#  with creation caching feature being removed.  This is equivalent to
+#  setting this property to 'false'.
+#
+(one-of?true|false)gplazma.enable.plugin-creation-caching = true
+
 
 #  -----------------------------------------------------------------------
 #         Properties for gPlazma plugins

skel/share/services/gplazma.batch

@@ -5,6 +5,7 @@ check -strong gplazma.cell.name
 check -strong gplazma.cell.limits.threads
 check -strong gplazma.configuration.file
 check -strong gplazma.service.pnfsmanager
+check -strong gplazma.enable.plugin-creation-caching
 
 create org.dcache.cells.UniversalSpringCell "${gplazma.cell.name}" \
    "classpath:org/dcache/services/login/gplazma.xml \