code: /*
   * 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.skywalking.oap.server.receiver.envoy;
  
  import com.google.protobuf.TextFormat;
  import io.envoyproxy.envoy.service.metrics.v2.MetricsServiceGrpc;
  import io.envoyproxy.envoy.service.metrics.v3.StreamMetricsMessage;
  import io.envoyproxy.envoy.service.metrics.v3.StreamMetricsResponse;
  import io.grpc.ManagedChannel;
  import io.grpc.ManagedChannelBuilder;
  import io.grpc.stub.StreamObserver;
  import io.prometheus.client.Metrics;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.util.concurrent.Executors;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.concurrent.TimeUnit;
  
  public class MetricServiceGRPCHandlerTestMain {
  
      public static void main(String[] args) throws InterruptedException {
          ManagedChannel channel = ManagedChannelBuilder.forAddress("localhost", 11800).usePlaintext().build();
  
          MetricsServiceGrpc.MetricsServiceStub stub = MetricsServiceGrpc.newStub(channel);
  
          ScheduledExecutorService executor = Executors.newSingleThreadScheduledExecutor();
          executor.schedule(() -> {
              try {
                  send(stub);
              } catch (IOException e) {
                  e.printStackTrace();
              } catch (InterruptedException e) {
                  e.printStackTrace();
              }
          }, 1, TimeUnit.SECONDS);
          Thread.sleep(5000L);
          executor.shutdown();
      }
  
      private static void send(
          final MetricsServiceGrpc.MetricsServiceStub stub) throws IOException, InterruptedException {
          StreamObserver<StreamMetricsMessage> messageStreamObserver = stub.streamMetrics(new StreamObserver<StreamMetricsResponse>() {
              @Override
              public void onNext(StreamMetricsResponse response) {
  
              }
  
              @Override
              public void onError(Throwable throwable) {
  
              }
  
              @Override
              public void onCompleted() {
  
              }
          });
          int countdown = 20;
          while (countdown-- > 0) {
              try (InputStreamReader isr = new InputStreamReader(getResourceAsStream("envoy-metric.msg"))) {
                  StreamMetricsMessage.Builder requestBuilder = StreamMetricsMessage.newBuilder();
                  TextFormat.getParser().merge(isr, requestBuilder);
  
                  for (Metrics.MetricFamily.Builder builder : requestBuilder.getEnvoyMetricsBuilderList()) {
                      for (Metrics.Metric.Builder metricBuilder : builder.getMetricBuilderList()) {
                          metricBuilder.setTimestampMs(System.currentTimeMillis());
                      }
                  }
                  messageStreamObserver.onNext(requestBuilder.build());
                  Thread.sleep(200L);
              }
          }
      }
  
      private static InputStream getResourceAsStream(final String resource) {
          final InputStream in = getContextClassLoader().getResourceAsStream(resource);
          return in == null ? MetricServiceGRPCHandlerTestMain.class.getResourceAsStream(resource) : in;
      }
  
      private static ClassLoader getContextClassLoader() {
          return Thread.currentThread().getContextClassLoader();
      }
  }
  