text: /*
   * 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.nifi.reporting.ambari;
  
  import org.apache.nifi.annotation.configuration.DefaultSchedule;
  import org.apache.nifi.annotation.documentation.CapabilityDescription;
  import org.apache.nifi.annotation.documentation.Tags;
  import org.apache.nifi.annotation.lifecycle.OnScheduled;
  import org.apache.nifi.components.PropertyDescriptor;
  import org.apache.nifi.controller.ConfigurationContext;
  import org.apache.nifi.controller.status.ProcessGroupStatus;
  import org.apache.nifi.expression.ExpressionLanguageScope;
  import org.apache.nifi.metrics.jvm.JmxJvmMetrics;
  import org.apache.nifi.metrics.jvm.JvmMetrics;
  import org.apache.nifi.processor.util.StandardValidators;
  import org.apache.nifi.reporting.AbstractReportingTask;
  import org.apache.nifi.reporting.ReportingContext;
  import org.apache.nifi.reporting.util.metrics.MetricsService;
  import org.apache.nifi.reporting.util.metrics.api.MetricsBuilder;
  import org.apache.nifi.scheduling.SchedulingStrategy;
  
  import javax.json.Json;
  import javax.json.JsonBuilderFactory;
  import javax.json.JsonObject;
  import javax.ws.rs.client.Client;
  import javax.ws.rs.client.ClientBuilder;
  import javax.ws.rs.client.Entity;
  import javax.ws.rs.client.Invocation;
  import javax.ws.rs.client.WebTarget;
  import javax.ws.rs.core.Response;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.TimeUnit;
  
  @Tags({"reporting", "ambari", "metrics"})
  @CapabilityDescription("Publishes metrics from NiFi to Ambari Metrics Service (AMS). Due to how the Ambari Metrics Service " +
          "works, this reporting task should be scheduled to run every 60 seconds. Each iteration it will send the metrics " +
          "from the previous iteration, and calculate the current metrics to be sent on next iteration. Scheduling this reporting " +
          "task at a frequency other than 60 seconds may produce unexpected results.")
  @DefaultSchedule(strategy = SchedulingStrategy.TIMER_DRIVEN, period = "1 min")
  public class AmbariReportingTask extends AbstractReportingTask {
  
      static final PropertyDescriptor METRICS_COLLECTOR_URL = new PropertyDescriptor.Builder()
              .name("Metrics Collector URL")
              .description("The URL of the Ambari Metrics Collector Service")
              .required(true)
              .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
              .defaultValue("http://localhost:6188/ws/v1/timeline/metrics")
              .addValidator(StandardValidators.URL_VALIDATOR)
              .build();
  
      static final PropertyDescriptor APPLICATION_ID = new PropertyDescriptor.Builder()
              .name("Application ID")
              .description("The Application ID to be included in the metrics sent to Ambari")
              .required(true)
              .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
              .defaultValue("nifi")
              .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
              .build();
  
      static final PropertyDescriptor HOSTNAME = new PropertyDescriptor.Builder()
              .name("Hostname")
              .description("The Hostname of this NiFi instance to be included in the metrics sent to Ambari")
              .required(true)
              .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
              .defaultValue("${hostname(true)}")
              .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
              .build();
  
      static final PropertyDescriptor PROCESS_GROUP_ID = new PropertyDescriptor.Builder()
              .name("Process Group ID")
              .description("If specified, the reporting task will send metrics about this process group only. If"
                      + " not, the root process group is used and global metrics are sent.")
              .required(false)
              .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
              .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
              .build();
  
      private volatile Client client;
      private volatile JsonBuilderFactory factory;
      private volatile JvmMetrics virtualMachineMetrics;
      private volatile JsonObject previousMetrics = null;
  
      private final MetricsService metricsService = new MetricsService();
  
      @Override
      protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
          final List<PropertyDescriptor> properties = new ArrayList<>();
          properties.add(METRICS_COLLECTOR_URL);
          properties.add(APPLICATION_ID);
          properties.add(HOSTNAME);
          properties.add(PROCESS_GROUP_ID);
          return properties;
      }
  
      @OnScheduled
      public void setup(final ConfigurationContext context) throws IOException {
          final Map<String, ?> config = Collections.emptyMap();
          factory = Json.createBuilderFactory(config);
          client = createClient();
          virtualMachineMetrics = JmxJvmMetrics.getInstance();
          previousMetrics = null;
      }
  
      // used for testing to allow tests to override the client
      protected Client createClient() {
          return ClientBuilder.newClient();
      }
  
      @Override
      public void onTrigger(final ReportingContext context) {
          final String metricsCollectorUrl = context.getProperty(METRICS_COLLECTOR_URL).evaluateAttributeExpressions().getValue();
          final String applicationId = context.getProperty(APPLICATION_ID).evaluateAttributeExpressions().getValue();
          final String hostname = context.getProperty(HOSTNAME).evaluateAttributeExpressions().getValue();
  
          final boolean pgIdIsSet = context.getProperty(PROCESS_GROUP_ID).isSet();
          final String processGroupId = pgIdIsSet ? context.getProperty(PROCESS_GROUP_ID).evaluateAttributeExpressions().getValue() : null;
  
          final long start = System.currentTimeMillis();
  
          // send the metrics from last execution
          if (previousMetrics != null) {
              final WebTarget metricsTarget = client.target(metricsCollectorUrl);
              final Invocation.Builder invocation = metricsTarget.request();
  
              final Entity<String> entity = Entity.json(previousMetrics.toString());
              getLogger().debug("Sending metrics {} to Ambari", new Object[]{entity.getEntity()});
  
              final Response response = invocation.post(entity);
              if (response.getStatus() == Response.Status.OK.getStatusCode()) {
                  final long completedMillis = TimeUnit.NANOSECONDS.toMillis(System.currentTimeMillis() - start);
                  getLogger().info("Successfully sent metrics to Ambari in {} ms", new Object[]{completedMillis});
              } else {
                  final String responseEntity = response.hasEntity() ? response.readEntity(String.class) : "unknown error";
                  getLogger().error("Error sending metrics to Ambari due to {} - {}", new Object[]{response.getStatus(), responseEntity});
              }
          }
  
          // calculate the current metrics, but store them to be sent next time
          final ProcessGroupStatus status = processGroupId == null ? context.getEventAccess().getControllerStatus() : context.getEventAccess().getGroupStatus(processGroupId);
  
          if(status != null) {
              final Map<String,String> statusMetrics = metricsService.getMetrics(status, pgIdIsSet);
              final Map<String,String> jvmMetrics = metricsService.getMetrics(virtualMachineMetrics);
  
              final MetricsBuilder metricsBuilder = new MetricsBuilder(factory);
  
              final JsonObject metricsObject = metricsBuilder
                      .applicationId(applicationId)
                      .instanceId(status.getId())
                      .hostname(hostname)
                      .timestamp(start)
                      .addAllMetrics(statusMetrics)
                      .addAllMetrics(jvmMetrics)
                      .build();
  
              previousMetrics = metricsObject;
          } else {
              getLogger().error("No process group status with ID = {}", new Object[]{processGroupId});
              previousMetrics = null;
          }
      }
  
  }
  