content: /*
   * 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.ambari.server.audit.request;
  
  
  import java.util.Set;
  
  import org.apache.ambari.server.api.services.Request;
  import org.apache.ambari.server.api.services.Result;
  import org.apache.ambari.server.api.services.ResultStatus;
  import org.apache.ambari.server.audit.AuditLogger;
  import org.apache.ambari.server.audit.event.AuditEvent;
  import org.apache.ambari.server.audit.request.eventcreator.RequestAuditEventCreator;
  import org.apache.ambari.server.controller.spi.Resource;
  
  import com.google.inject.Inject;
  import com.google.inject.Singleton;
  
  /**
   * The purpose of this class is to create audit log entries for the HTTP requests
   */
  @Singleton
  public class RequestAuditLoggerImpl implements RequestAuditLogger {
  
    /**
     * Priorities for searching the proper creator
     */
    private static final int REQUEST_TYPE_PRIORITY = 1;
    private static final int RESULT_STATUS_PRIORITY = 2;
    private static final int RESOURCE_TYPE_PRIORITY = 4;
  
    /**
     * Container for the {@link RequestAuditEventCreator}
     */
    private Set<RequestAuditEventCreator> creators;
  
    /**
     * Audit logger that receives {@link AuditEvent}s and does the actual logging
     */
    private AuditLogger auditLogger;
  
    /**
     * Injecting dependencies through the constructor
     * @param auditLogger Audit Logger
     * @param creatorSet Set of plugins that are registered for requests
     */
    @Inject
    public RequestAuditLoggerImpl(AuditLogger auditLogger, Set<RequestAuditEventCreator> creatorSet) {
      this.auditLogger = auditLogger;
      this.creators = creatorSet;
    }
  
    /**
     * Finds the proper creator, then creates and logs and {@link AuditEvent}
     * @param request
     * @param result
     */
    @Override
    public void log(Request request, Result result) {
      if(!auditLogger.isEnabled()) {
        return;
      }
  
      Resource.Type resourceType = request.getResource().getResourceDefinition().getType();
      Request.Type requestType = request.getRequestType();
      ResultStatus resultStatus = result.getStatus();
  
      RequestAuditEventCreator creator = selectCreator(resourceType, resultStatus, requestType);
      if (creator != null) {
        AuditEvent ae = creator.createAuditEvent(request, result);
        if (ae != null) {
          auditLogger.log(ae);
        }
      }
    }
  
    /**
     * Select the proper creator. Priority order: resourceType > resultStatus > requestType
     * The most matching creator is returned
     * If there is no creator found, then null is returned.
     * @param resourceType
     * @param requestType
     * @param resultStatus
     * @return
     */
    private RequestAuditEventCreator selectCreator(Resource.Type resourceType, ResultStatus resultStatus, Request.Type requestType) {
  
      RequestAuditEventCreator selected = null;
      Integer priority = -1;
  
      for (RequestAuditEventCreator creator : creators) {
        Integer creatorPriority = getPriority(creator, resourceType, resultStatus, requestType);
        if (creatorPriority != null && priority < creatorPriority) {
          priority = creatorPriority;
          selected = creator;
        }
      }
      return selected;
    }
  
    /**
     * Calculates the creator priority for the actual resouce type, result status and request type
     * @param creator
     * @param resourceType
     * @param resultStatus
     * @param requestType
     * @return
     */
    private Integer getPriority(RequestAuditEventCreator creator, Resource.Type resourceType, ResultStatus resultStatus, Request.Type requestType) {
      Integer priority = 0;
  
      if (isIncompatible(creator, resourceType, resultStatus, requestType)) {
        return null;
      }
  
      priority += creator.getRequestTypes() != null && creator.getRequestTypes().contains(requestType) ? REQUEST_TYPE_PRIORITY : 0;
      priority += creator.getResultStatuses() != null && creator.getResultStatuses().contains(resultStatus.getStatus()) ? RESULT_STATUS_PRIORITY : 0;
      priority += creator.getResourceTypes() != null && creator.getResourceTypes().contains(resourceType) ? RESOURCE_TYPE_PRIORITY : 0;
      return priority;
    }
  
    /**
     * Checks if the creator is a possible candidate for creating audit log event for the request
     * @param creator
     * @param resourceType
     * @param resultStatus
     * @param requestType
     * @return
     */
    private boolean isIncompatible(RequestAuditEventCreator creator, Resource.Type resourceType, ResultStatus resultStatus, Request.Type requestType) {
      return creator.getRequestTypes() != null && !creator.getRequestTypes().contains(requestType) ||
        creator.getResultStatuses() != null && !creator.getResultStatuses().contains(resultStatus.getStatus()) ||
        creator.getResourceTypes() != null && !creator.getResourceTypes().contains(resourceType);
    }
  }
  