content: /*
   * Copyright The OpenTelemetry Authors
   * SPDX-License-Identifier: Apache-2.0
   */
  
  package io.opentelemetry.instrumentation.api.incubator.semconv.net;
  
  import io.opentelemetry.api.common.AttributeKey;
  import io.opentelemetry.api.common.AttributesBuilder;
  import io.opentelemetry.context.Context;
  import io.opentelemetry.instrumentation.api.instrumenter.AttributesExtractor;
  import io.opentelemetry.instrumentation.api.semconv.network.ServerAttributesGetter;
  import javax.annotation.Nullable;
  
  /**
   * Extractor of the {@code peer.service} span attribute, described in <a
   * href="https://github.com/open-telemetry/semantic-conventions/blob/main/docs/general/attributes.md#general-remote-service-attributes">the
   * specification</a>.
   */
  public final class PeerServiceAttributesExtractor<REQUEST, RESPONSE>
      implements AttributesExtractor<REQUEST, RESPONSE> {
  
    // copied from PeerIncubatingAttributes
    private static final AttributeKey<String> PEER_SERVICE = AttributeKey.stringKey("peer.service");
  
    private final ServerAttributesGetter<REQUEST> attributesGetter;
    private final PeerServiceResolver peerServiceResolver;
  
    // visible for tests
    PeerServiceAttributesExtractor(
        ServerAttributesGetter<REQUEST> attributesGetter, PeerServiceResolver peerServiceResolver) {
      this.attributesGetter = attributesGetter;
      this.peerServiceResolver = peerServiceResolver;
    }
  
    /**
     * Returns a new {@link PeerServiceAttributesExtractor} that will use the passed {@code
     * attributesGetter} instance to determine the value of the {@code peer.service} attribute.
     */
    public static <REQUEST, RESPONSE> AttributesExtractor<REQUEST, RESPONSE> create(
        ServerAttributesGetter<REQUEST> attributesGetter, PeerServiceResolver peerServiceResolver) {
      return new PeerServiceAttributesExtractor<>(attributesGetter, peerServiceResolver);
    }
  
    @Override
    public void onStart(AttributesBuilder attributes, Context parentContext, REQUEST request) {}
  
    @SuppressWarnings("deprecation") // old semconv
    @Override
    public void onEnd(
        AttributesBuilder attributes,
        Context context,
        REQUEST request,
        @Nullable RESPONSE response,
        @Nullable Throwable error) {
  
      if (peerServiceResolver.isEmpty()) {
        // optimization for common case
        return;
      }
  
      String serverAddress = attributesGetter.getServerAddress(request);
      Integer serverPort = attributesGetter.getServerPort(request);
      String peerService = mapToPeerService(serverAddress, serverPort);
      if (peerService != null) {
        attributes.put(PEER_SERVICE, peerService);
      }
    }
  
    @Nullable
    private String mapToPeerService(@Nullable String host, @Nullable Integer port) {
      if (host == null) {
        return null;
      }
      return peerServiceResolver.resolveService(host, port, null);
    }
  }
  