handlers/handler-tracing-zipkin/src/main/java/org/apache/servicecomb/tracing/zipkin/ZipkinConsumerDelegate.java

/*
 * 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.servicecomb.tracing.zipkin;

import org.apache.servicecomb.core.Invocation;
import org.apache.servicecomb.swagger.invocation.Response;

import brave.Span;
import brave.Tracing;
import brave.http.HttpClientRequest;
import brave.http.HttpClientResponse;
import brave.http.HttpClientHandler;
import brave.http.HttpTracing;
import brave.propagation.Propagation.Setter;
import brave.propagation.TraceContext.Injector;

class ZipkinConsumerDelegate implements ZipkinTracingDelegate {

  private final HttpClientHandler<HttpClientRequest, HttpClientResponse> handler;

  private final HttpTracing httpTracing;

  private final Injector<Invocation> injector;

  private final HttpClientResponseWrapper responseWrapper;

  private final HttpClientRequestWrapper requestWrapper;

  ZipkinConsumerDelegate(HttpTracing httpTracing) {
    this.httpTracing = httpTracing;
    this.injector = httpTracing.tracing().propagation().injector(injector());
    this.handler = HttpClientHandler.create(httpTracing);
    this.responseWrapper = new HttpClientResponseWrapper();
    this.requestWrapper = new HttpClientRequestWrapper();
  }

  @Override
  public Span createSpan(Invocation invocation) {
    return handler.handleSend(requestWrapper.invocation(invocation));
  }

  @Override
  public void onResponse(Span span, Response response, Throwable error) {
    handler.handleReceive(responseWrapper.response(response).throwable(error).request(requestWrapper), span);
  }

  @Override
  public String name() {
    return "Zipkin consumer";
  }

  @Override
  public Tracing tracer() {
    return httpTracing.tracing();
  }

  private Setter<Invocation, String> injector() {
    return (invocation, key, value) -> invocation.getContext().put(key, value);
  }
}