码霸霸

问题说明

在zuul中使用apache client请求时，traceid | spanid | parentspanid都能传递到下一个服务中，当切换到okhttp时，以上信息没有传递过去，在下一个服务中出现新的traceid，对于服务的链路从gateway开始跟踪产生了影响。现象如下：

ribbon:
  http:
    client:
      enabled: false
  okhttp:
    enabled: true

原有分析

使用apache client，链路追踪相关的id会随着handler传递到下一个服务，但是使用okhttp就忽略了链路追踪的id；handler中并没有包含任何id，这样在下一个服务中，就会产生一个新的id，从而是链路追踪断链。

解决方案

以下就是解决该问题的一种方式。
首先定义一个Interceptor，用于将拦截到的请求头里面添加上traceid | spanid | parentspanid等信息：

import java.io.IOException;
 
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
 
import brave.Tracer;
import brave.internal.HexCodec;
import brave.internal.Platform;
import brave.propagation.TraceContext;
import okhttp3.Headers;
import okhttp3.Interceptor;
import okhttp3.Request;
import okhttp3.Response;
 
/**
 * okhttp过滤器，添加与trace集成的功能。 实现方式参考see also
 * @see brave.propagation.B3Propagation
 * @see org.springframework.cloud.netflix.ribbon.okhttp.OkHttpRibbonRequest
 */
public class OkhttpTraceInterceptor implements Interceptor {
 
    Logger logger = LoggerFactory.getLogger(OkhttpTraceInterceptor.class);
 
  
    /**
     * 128 or 64-bit trace ID lower-hex encoded into 32 or 16 characters (required)
     */
    static final String TRACE_ID_NAME = "X-B3-TraceId";
    /**
     * 64-bit span ID lower-hex encoded into 16 characters (required)
     */
    static final String SPAN_ID_NAME = "X-B3-SpanId";
    /**
     * 64-bit parent span ID lower-hex encoded into 16 characters (absent on root span)
     */
    static final String PARENT_SPAN_ID_NAME = "X-B3-ParentSpanId";
    /**
     * "1" means report this span to the tracing system, "0" means do not. (absent means defer the
     * decision to the receiver of this header).
     */
    static final String SAMPLED_NAME = "X-B3-Sampled";
 
    @Autowired
    Tracer tracer;
 
    /**
     * 将X-B3-TraceId | X-B3-SpanId | X-B3-ParentSpanId添加到请求的头部，再将请求发送出去
     */
    @Override
    public Response intercept(Chain chain) throws IOException {
        Request request = chain.request();
        TraceContext traceContext = tracer.currentSpan().context(); 
        //copy all headers to newheaders
        Headers.Builder headers = request.headers().newBuilder();
        //add traceid | spanid | parentspanid to headers
        headers.add(TRACE_ID_NAME, traceContext.traceIdString());
        // headers.add(SPAN_ID_NAME, traceContext.spanIdString());
        headers.add(SPAN_ID_NAME, HexCodec.toLowerHex(nextId()));//set next spanid
        String parentId = traceContext.parentIdString();
        if(parentId == null) {
            parentId = HexCodec.toLowerHex(traceContext.spanId());//set parentid = spanid(root) when null
        }
        headers.add(PARENT_SPAN_ID_NAME, parentId);
        // headers.add(SAMPLED_NAME,"1");
    
        //rebuild a new request
        request = request.newBuilder().headers(headers.build()).build();
        Response response = chain.proceed(request);
 
        //将traceid返回去给调用方，如浏览器发起的请求，可在浏览器看到该信息，方便定位
        Headers.Builder responseHeadersBuilder = response.headers()
                                                        .newBuilder()
                                                        .add(TRACE_ID_NAME, traceContext.traceIdString());
        response = response.newBuilder().headers(responseHeadersBuilder.build()).build();
 
        return response;
    }
 
    /** Generates a new 64-bit ID, taking care to dodge zero which can be confused with absent */
    long nextId() {
        long nextId = Platform.get().randomLong();
        while (nextId == 0L) {
        nextId = Platform.get().randomLong();
        }
        return nextId;
    }
 
}

然后定义BeanPostProcessor，在okhttpclient的bean初始化之前将上面的过滤器添加到client中：

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.stereotype.Component;
 
/**
 *
 * 为okhttpclient的bean添加过滤器
 */
@Configuration
@Component
public class OkHttpTracePostProcessor implements BeanPostProcessor {
    Logger logger = LoggerFactory.getLogger(OkHttpTracePostProcessor.class);
 
    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        if(bean instanceof okhttp3.OkHttpClient){
            okhttp3.OkHttpClient client = (okhttp3.OkHttpClient)bean;
            bean = client.newBuilder()
                .addInterceptor(okhttpTraceInterceptor())//添加过滤器，该过滤器主要是将在请求头中添加追踪信息
                .build();
            logger.info("addInterceptor okhttpTraceInterceptor to bean:{}",beanName);
        }
   
        return bean;
    }
  
    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        return bean;
    }
  
   
    @Bean
    OkhttpTraceInterceptor okhttpTraceInterceptor() {
        return new OkhttpTraceInterceptor();
    }
}

如果已经定义好okhttpclient的bean（也即以上的OkHttpTracePostProcessor的init方法能捕捉到okhttpclient），那么此时就完工了。如果还没有client，则自定义一个bean：

import java.util.concurrent.TimeUnit;
 
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
 
import feign.okhttp.OkHttpClient;
import okhttp3.ConnectionPool;
 
/**
 * 
 * OkHttpClient集成Trace跟踪的自动化配置部分
 */
@Configuration
public class OkHttpTraceAutoConfig {
 
    /**
     * 如果还未定义OkHttpClient的bean，则采用此OkHttpClient
     * @return
     */
    @Bean
    @ConditionalOnMissingBean(OkHttpClient.class)
    public okhttp3.OkHttpClient okHttpClient(){
        return new okhttp3.OkHttpClient.Builder()
                .connectTimeout(2, TimeUnit.SECONDS)
                .readTimeout(3,TimeUnit.SECONDS)
                .writeTimeout(3, TimeUnit.SECONDS)
                .retryOnConnectionFailure(true)
                .connectionPool(new ConnectionPool(20,10L,TimeUnit.SECONDS))
                .build();
    }
 
}

以上bean会在没有okhttpclient的时候初始化一个bean，然后postprocessor捕捉添加interceptor，便能将信息添加到头部。自此，便完成了traceid等信息的传递。
另，如果需要传递其他信息，比如用户的标签，也可采用类似的方式实现。

转载完善自：https://blog.csdn.net/shuidexiongdi/article/details/95359196

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标题：zuul使用okhttp使zipkin链路id传递失败的解决方案
作者：码霸霸
地址：https://blog.lupf.cn/articles/2020/11/09/1604915008530.html