zipkin-java-brave源码分析（三）

什么是brave

brave是zipkin官方提供的java版本zipkin-client实现

brave提供的功能

<modules>
<module>brave-core</module>
<module>brave-benchmarks</module>
<module>brave-http</module>
<module>brave-core-spring</module>
<module>brave-resteasy-spring</module>
<module>brave-resteasy3-spring</module>
<module>brave-spancollector-http</module>
<module>brave-spancollector-scribe</module>
<module>brave-spancollector-kafka</module>
<module>brave-spancollector-local</module>
<module>brave-sampler-zookeeper</module>
<module>brave-jersey</module>
<module>brave-jersey2</module>
<module>brave-jaxrs2</module>
<module>brave-grpc</module>
<module>brave-apache-http-interceptors</module>
<module>brave-spring-web-servlet-interceptor</module>
<module>brave-spring-resttemplate-interceptors</module>
<module>brave-mysql</module>
<module>brave-web-servlet-filter</module>
<module>brave-okhttp</module>
</modules>

基于http提供brave源码分析

brave-spancollector-http

提供httpCollector收集器

brave-web-servlet-filter

基于http请求提供过滤器

brave-apache-http-interceptors

基于apache-http-client发起气球提供拦截器

基于springboot启动

step1配置

针对collector的SpanCollector

针对http请求的filter BraveServletFilter

针对数据发送的Brave

针对http-client请求的拦截器BraveHttpRequestInterceptor，BraveHttpResponseInterceptor

@Configuration
public class ZipkinConfig {
//span（一次请求信息或者一次链路调用）信息收集器
@Bean
public SpanCollector spanCollector() {
Config config = HttpSpanCollector.Config.builder()
.compressionEnabled(false)// 默认false，span在transport之前是否会被gzipped
.connectTimeout(5000)
.flushInterval(1)
.readTimeout(6000)
.build();
return HttpSpanCollector.create("http://localhost:9411", config, new EmptySpanCollectorMetricsHandler());
}

//作为各调用链路，只需要负责将指定格式的数据发送给zipkin
@Bean
public Brave brave(SpanCollector spanCollector){
Builder builder = new Builder("service1");//指定serviceName
builder.spanCollector(spanCollector);
builder.traceSampler(Sampler.create(1));//采集率
return builder.build();
}

//设置server的（服务端收到请求和服务端完成处理，并将结果发送给客户端）过滤器
@Bean
public BraveServletFilter braveServletFilter(Brave brave) {
BraveServletFilter filter = new BraveServletFilter(brave.serverRequestInterceptor(),
brave.serverResponseInterceptor(), new DefaultSpanNameProvider());
return filter;
}

//设置client的（发起请求和获取到服务端返回信息）拦截器
@Bean
public CloseableHttpClient okHttpClient(Brave brave){
CloseableHttpClient httpclient = HttpClients.custom()
.addInterceptorFirst(new BraveHttpRequestInterceptor(brave.clientRequestInterceptor(), new DefaultSpanNameProvider()))
.addInterceptorFirst(new BraveHttpResponseInterceptor(brave.clientResponseInterceptor()))
.build();
return httpclient;
}

}

基于http发起请求服务端处理

post or get url : http://localhost/service1

相关代码请查看 zipkin简单介绍及环境搭建（一）

流程图



point

针对请求，如果Sampledheader包含(X-B3-Sampled)会获取header中的ParentSpanId,TraceId,SpanId直接返回，否者会认为这是一个新的请求会构建Span
HttpServerRequestAdapter.getTraceData()
public TraceData getTraceData() {
final String sampled = serverRequest.getHttpHeaderValue(BraveHttpHeaders.Sampled.getName());
if (sampled != null) {
if (sampled.equals("0") || sampled.toLowerCase().equals("false")) {
return TraceData.builder().sample(false).build();
} else {
final String parentSpanId = serverRequest.getHttpHeaderValue(BraveHttpHeaders.ParentSpanId.getName());
final String traceId = serverRequest.getHttpHeaderValue(BraveHttpHeaders.TraceId.getName());
final String spanId = serverRequest.getHttpHeaderValue(BraveHttpHeaders.SpanId.getName());

if (traceId != null && spanId != null) {
SpanId span = getSpanId(traceId, spanId, parentSpanId);
return TraceData.builder().sample(true).spanId(span).build();
}
}
}
return TraceData.builder().build();
}
针对请求的采样
traceSampler().isSampled(newTraceId)，没有使用zk情况下CountingSampler来决定
public synchronized boolean isSampled(long traceIdIgnored) {
boolean result = sampleDecisions.get(i++);
if (i == 100) i = 0;
return result;
}

基于apache-http发起请求

流程图

如何在代码中添加自己的annotation or binaryAnnotation

直接注入Brave即可 ps(不建议这样做，代码侵入。 zipkin不建议添加大量数据)

@RestController
public class ZipkinBraveController {

@Autowired
private CloseableHttpClient httpClient;
@Autowired
private com.github.kristofa.brave.Brave brave;

@GetMapping("/service1")
public String myboot() throws Exception {
brave.serverTracer().submitBinaryAnnotation("状态", "成功");
Thread.sleep(100);//100ms
HttpGet get = new HttpGet("http://localhost:81/test");
CloseableHttpResponse execute = httpClient.execute(get);
/*
* 1、执行execute()的前后，会执行相应的拦截器（cs,cr）
* 2、请求在被调用方执行的前后，也会执行相应的拦截器（sr,ss）
*/
return EntityUtils.toString(execute.getEntity(), "utf-8");
}
}

ps

如果collector要使用kafka直接切换spanController即可，需要server端进行对应配置

client端
KafkaSpanCollector.create(KafkaSpanCollector.Config.builder().kafkaProperties(null).build(), new EmptySpanCollectorMetricsHandler());

server端需要配置kafka配置
final class KafkaZooKeeperSetCondition extends SpringBootCondition {
static final String PROPERTY_NAME = "zipkin.collector.kafka.zookeeper";

@Override
public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata a) {
String kafkaZookeeper = context.getEnvironment().getProperty(PROPERTY_NAME);
return kafkaZookeeper == null || kafkaZookeeper.isEmpty() ?
ConditionOutcome.noMatch(PROPERTY_NAME + " isn't set") :
ConditionOutcome.match();
}
}

链接

zipkin简单介绍及环境搭建（一）

zipkin-server源码分析（二）