GUACAMOLE-1224: Add a default, global event listener providing logging.

guacamole/src/main/java/org/apache/guacamole/event/AffectedObject.java

@@ -0,0 +1,124 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.guacamole.event;
+
+import org.apache.guacamole.net.auth.Nameable;
+import org.apache.guacamole.net.event.DirectoryEvent;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Loggable representation of the object affected by an operation.
+ */
+public class AffectedObject implements LoggableDetail {
+
+    /**
+     * Logger for this class.
+     */
+    private static final Logger logger = LoggerFactory.getLogger(AffectedObject.class);
+    
+    /**
+     * The event representing the requested operation.
+     */
+    private final DirectoryEvent<?> event;
+
+    /**
+     * Creates a new AffectedObject representing the object affected by the
+     * operation described by the given event.
+     *
+     * @param event
+     *     The event representing the operation.
+     */
+    public AffectedObject(DirectoryEvent<?> event) {
+        this.event = event;
+    }
+
+    @Override
+    public String toString() {
+
+        Object object = event.getObject();
+        String identifier = event.getObjectIdentifier();
+
+        String objectType;
+        String name = null; // Not all objects have names
+
+        // Obtain name of object (if applicable and available)
+        if (object instanceof Nameable) {
+            try {
+                name = ((Nameable) object).getName();
+            }
+            catch (RuntimeException | Error e) {
+                logger.debug("Name of object \"{}\" could not be retrieved.", identifier, e);
+            }
+        }
+
+        // Determine type of object
+        switch (event.getDirectoryType()) {
+
+            // Active connections
+            case ACTIVE_CONNECTION:
+                objectType = "active connection";
+                break;
+
+            // Connections
+            case CONNECTION:
+                objectType = "connection";
+                break;
+
+            // Connection groups
+            case CONNECTION_GROUP:
+                objectType = "connection group";
+                break;
+
+            // Sharing profiles
+            case SHARING_PROFILE:
+                objectType = "sharing profile";
+                break;
+
+            // Users
+            case USER:
+                objectType = "user";
+                break;
+
+            // User groups
+            case USER_GROUP:
+                objectType = "user group";
+                break;
+
+            // Unknown
+            default:
+                objectType = (object != null) ? object.getClass().toString() : "an unknown object";
+                
+        }
+
+        // Describe at least the type of the object and its identifier,
+        // including the name of the object, as well, if available
+        if (identifier != null) {
+            if (name != null)
+                return objectType + " \"" + identifier + "\" (currently named \"" + name + "\")";
+            else
+                return objectType + " \"" + identifier + "\"";
+        }
+        else
+            return objectType;
+
+    }
+    
+}

guacamole/src/main/java/org/apache/guacamole/event/EventLoggingListener.java

@@ -0,0 +1,130 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.guacamole.event;
+
+import javax.annotation.Nonnull;
+import org.apache.guacamole.GuacamoleException;
+import org.apache.guacamole.GuacamoleResourceNotFoundException;
+import org.apache.guacamole.net.event.DirectoryEvent;
+import org.apache.guacamole.net.event.DirectoryFailureEvent;
+import org.apache.guacamole.net.event.DirectorySuccessEvent;
+import org.apache.guacamole.net.event.listener.Listener;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Listener that records each event that occurs in the logs, such as changes
+ * made to objects via the REST API.
+ */
+public class EventLoggingListener implements Listener {
+
+    /**
+     * Logger for this class.
+     */
+    private final Logger logger = LoggerFactory.getLogger(EventLoggingListener.class);
+
+    /**
+     * Logs that an operation was performed on an object within a Directory
+     * successfully.
+     *
+     * @param event
+     *     The event describing the operation successfully performed on the
+     *     object.
+     */
+    private void logSuccess(DirectorySuccessEvent<?> event) {
+        DirectoryEvent.Operation op = event.getOperation();
+        switch (op) {
+
+            case GET:
+                logger.debug("{} successfully accessed/retrieved {}", new RequestingUser(event), new AffectedObject(event));
+                break;
+
+            case ADD:
+                logger.info("{} successfully created {}", new RequestingUser(event), new AffectedObject(event));
+                break;
+
+            case UPDATE:
+                logger.info("{} successfully updated {}", new RequestingUser(event), new AffectedObject(event));
+                break;
+
+            case REMOVE:
+                logger.info("{} successfully deleted {}", new RequestingUser(event), new AffectedObject(event));
+                break;
+
+            default:
+                logger.warn("DirectoryEvent operation type has no corresponding log message implemented: {}", op);
+                logger.info("{} successfully performed an unknown action on {} {}", new RequestingUser(event), new AffectedObject(event));
+
+        }
+    }
+
+    /**
+     * Logs that an operation failed to be performed on an object within a
+     * Directory.
+     *
+     * @param event
+     *     The event describing the operation that failed.
+     */
+    private void logFailure(DirectoryFailureEvent<?> event) {
+        DirectoryEvent.Operation op = event.getOperation();
+        switch (op) {
+
+            case GET:
+                if (event.getFailure() instanceof GuacamoleResourceNotFoundException)
+                    logger.debug("{} failed to access/retrieve {}: {}", new RequestingUser(event), new AffectedObject(event), new Failure(event));
+                else
+                    logger.info("{} failed to access/retrieve {}: {}", new RequestingUser(event), new AffectedObject(event), new Failure(event));
+                break;
+
+            case ADD:
+                logger.info("{} failed to create {}: {}", new RequestingUser(event), new AffectedObject(event), new Failure(event));
+                break;
+
+            case UPDATE:
+                logger.info("{} failed to update {}: {}", new RequestingUser(event), new AffectedObject(event), new Failure(event));
+                break;
+
+            case REMOVE:
+                logger.info("{} failed to delete {}: {}", new RequestingUser(event), new AffectedObject(event), new Failure(event));
+                break;
+
+            default:
+                logger.warn("DirectoryEvent operation type has no corresponding log message implemented: {}", op);
+                logger.info("{} failed to perform an unknown action on {}: {}", new RequestingUser(event), new AffectedObject(event), new Failure(event));
+
+        }
+    }
+
+    @Override
+    public void handleEvent(@Nonnull Object event) throws GuacamoleException {
+
+        if (event instanceof DirectorySuccessEvent)
+            logSuccess((DirectorySuccessEvent<?>) event);
+
+        else if (event instanceof DirectoryFailureEvent)
+            logFailure((DirectoryFailureEvent<?>) event);
+
+        else
+            logger.debug("Ignoring unknown/unimplemented event type: {}",
+                    event.getClass());
+
+    }
+
+}

guacamole/src/main/java/org/apache/guacamole/event/Failure.java

@@ -0,0 +1,56 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.guacamole.event;
+
+import org.apache.guacamole.net.event.FailureEvent;
+
+/**
+ * Loggable representation of a failure that occurred.
+ */
+public class Failure implements LoggableDetail {
+
+    /**
+     * The event representing the failure.
+     */
+    private final FailureEvent event;
+
+    /**
+     * Creates a new Failure representing the failure described by the given
+     * event.
+     *
+     * @param event 
+     *     The event representing the failure.
+     */
+    public Failure(FailureEvent event) {
+        this.event = event;
+    }
+
+    @Override
+    public String toString() {
+
+        Throwable failure = event.getFailure();
+        if (failure == null)
+            return "unknown error (no specific failure recorded)";
+
+        return failure.getMessage();
+        
+    }
+    
+}

guacamole/src/main/java/org/apache/guacamole/event/LoggableDetail.java

@@ -0,0 +1,39 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.guacamole.event;
+
+/**
+ * Provides a {@link #toString()} implementation that returns a human-readable
+ * string that is intended to be logged and which describes a particular detail
+ * of an event.
+ */
+public interface LoggableDetail {
+
+    /**
+     * {@inheritDoc}
+     * <p>
+     * A LoggableDetail implementation of toString() is required to return a
+     * string that is human-readable, describes a detail of a provided event,
+     * and that is intended to be logged.
+     */
+    @Override
+    String toString();
+
+}

guacamole/src/main/java/org/apache/guacamole/event/RequestingUser.java

@@ -0,0 +1,59 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.guacamole.event;
+
+import org.apache.guacamole.net.auth.AuthenticatedUser;
+import org.apache.guacamole.net.event.DirectoryEvent;
+
+/**
+ * Loggable representation of the user that requested an operation.
+ */
+public class RequestingUser implements LoggableDetail {
+
+    /**
+     * The event representing the requested operation.
+     */
+    private final DirectoryEvent<?> event;
+
+    /**
+     * Creates a new RequestingUser that represents the user that requested the
+     * operation described by the given event.
+     *
+     * @param event
+     *     The event representing the requested operation.
+     */
+    public RequestingUser(DirectoryEvent<?> event) {
+        this.event = event;
+    }
+
+    @Override
+    public String toString() {
+
+        AuthenticatedUser user = event.getAuthenticatedUser();
+        String identifier = user.getIdentifier();
+
+        if (AuthenticatedUser.ANONYMOUS_IDENTIFIER.equals(identifier))
+            return "Anonymous user (authenticated by \"" + user.getAuthenticationProvider().getIdentifier() + "\")";
+
+        return "User \"" + identifier + "\" (authenticated by \"" + user.getAuthenticationProvider().getIdentifier() + "\")";
+        
+    }
+
+}

guacamole/src/main/java/org/apache/guacamole/extension/ExtensionModule.java

@@ -35,6 +35,7 @@ import org.apache.guacamole.auth.file.FileAuthenticationProvider;
 import org.apache.guacamole.GuacamoleException;
 import org.apache.guacamole.GuacamoleServerException;
 import org.apache.guacamole.environment.Environment;
+import org.apache.guacamole.event.EventLoggingListener;
 import org.apache.guacamole.net.auth.AuthenticationProvider;
 import org.apache.guacamole.net.event.listener.Listener;
 import org.apache.guacamole.properties.StringSetProperty;
@@ -628,8 +629,9 @@ public class ExtensionModule extends ServletModule {
         final Set<String> toleratedAuthProviders = getToleratedAuthenticationProviders();
         loadExtensions(javaScriptResources, cssResources, toleratedAuthProviders);
 
-        // Always bind default file-driven auth last
+        // Always bind default file-driven auth and event logging last
         bindAuthenticationProvider(FileAuthenticationProvider.class, toleratedAuthProviders);
+        bindListener(EventLoggingListener.class);
 
         // Dynamically generate app.js and app.css from extensions
         serve("/app.js").with(new ResourceServlet(new SequenceResource(javaScriptResources)));