Zipkin服务端源码解析

r囧r小猫 2023-06-15 06:51 13阅读 0赞

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还记得这个我们zipkin系列的第一篇文章中提到过的架构图么，服务端组件就这么几个，很简单。

其中稍微有点内涵的也就是collector和storage分别提供了多种不同的实现，collector支持http、rabbitMq、kafka而storage支持内存、mysql、es

现在我们来了解一下服务端的实现。服务端开启自动装配使用的是`@EnableZipkinServer`注解

@Target(ElementType.TYPE)@Retention(RetentionPolicy.RUNTIME)@Documented@Import(InternalZipkinConfiguration.class)public @interface EnableZipkinServer { }

接着深入`InternalZipkinConfiguration`这个类

@Configuration@Import({ ZipkinServerConfiguration.class, TracingConfiguration.class, ZipkinQueryApiV2.class, ZipkinHttpCollector.class, MetricsHealthController.class})public class InternalZipkinConfiguration { }

可以看到这个类一共又引入了这么多的装配类，一个一个来分析吧

##### ZipkinServerConfiguration #####

这个类中，主要是配置了Zipkin的健康检查、web容器以及、默认的存储的方式的配置

其中健康检查的bean包括以下几个：

1.  `ZipkinHealthIndicator` 关于SpringBoot中健康检查的原理可以参考这篇文章：[SpringBoot健康检查实现原理][SpringBoot]
2.  健康检查的端口在这个类里`MetricsHealthController`，其中暴露了两个端口health和metrics

Web容器主要是由这个类负责的：`UndertowServletWebServerFactory`

`InMemoryConfiguration` 这个类则是存储的自动装配类，如果没有选择使用MySQL或者ES的话则会使用内存进行存储

##### TracingConfiguration #####

Zipkin服务端其实也会存储trace信息，这个时候就需要一些Client的配置。这个类里面就是这些配置 这里就不详细展开了

##### ZipkinQueryApiV2 #####

Zipkin V2版本的查询API，这个API是供Zipkin的UI界面使用的，其中包含这几个接口

1.  dependencies
2.  services
3.  spans
4.  traces
5.  /trace/\{traceIdHex\}

##### ZipkinHttpCollector #####

Zipkin默认的Collector使用http协议里收集Trace信息，这里就是本文的重点

核心接受请求的方法是`handleRequest`

public void handleRequest(HttpServerExchange exchange) throws Exception { boolean v2 = exchange.getRelativePath().equals("/api/v2/spans"); boolean v1 = !v2 && exchange.getRelativePath().equals("/api/v1/spans"); if (!v2 && !v1) { next.handleRequest(exchange); return; } if (!POST.equals(exchange.getRequestMethod())) { next.handleRequest(exchange); return; } String contentTypeValue = exchange.getRequestHeaders().getFirst(CONTENT_TYPE); boolean json = contentTypeValue == null || contentTypeValue.startsWith("application/json"); boolean thrift = !json && contentTypeValue.startsWith("application/x-thrift"); boolean proto = v2 && !json && contentTypeValue.startsWith("application/x-protobuf"); if (!json && !thrift && !proto) { exchange .setStatusCode(400) .getResponseSender() .send("unsupported content type " + contentTypeValue + "\n"); return; } HttpCollector collector = v2 ? (json ? JSON_V2 : PROTO3) : thrift ? THRIFT : JSON_V1; metrics.incrementMessages(); exchange.getRequestReceiver().receiveFullBytes(collector, errorCallback); }

这里一共有这么几个逻辑：

1.  首先判断接口版本，现在是v2版本
2.  然后判断数据格式，现在是json版本
3.  这里的collector的格式就是JSON\_V2
4.  添加监控数据
5.  数据处理

默认情况下使用的是异步方式处理数据的，这个处理的实现类是这个`AsyncReceiverImpl` 在`receiveFullBytes`方法中首先会对这次请求的参数进行处理，处理完成之后的json格式如下：

[{ "traceId": "e840c83e65d10358", "id": "e840c83e65d10358", "kind": "SERVER", "name": "get /user/getuser/{id}", "timestamp": 1574174031876439, "duration": 5911123, "localEndpoint": { "serviceName": "consumer-demo-feign", "ipv4": "192.168.0.15" }, "remoteEndpoint": { "ipv6": "::1", "port": 60716 }, "tags": { "http.method": "GET", "http.path": "/user/getUser/3", "mvc.controller.class": "UserController", "mvc.controller.method": "getUser" }}]

当json数据格式化之后，接下来就是具体的处理

public synchronized Call<Void> accept(List<Span> spans) { int delta = spans.size(); int spansToRecover = this.spansByTraceIdTimeStamp.size() + delta - this.maxSpanCount; this.evictToRecoverSpans(spansToRecover); Iterator var4 = spans.iterator(); while(var4.hasNext()) { Span span = (Span)var4.next(); long timestamp = span.timestampAsLong(); String lowTraceId = lowTraceId(span.traceId()); InMemoryStorage.TraceIdTimestamp traceIdTimeStamp = new InMemoryStorage.TraceIdTimestamp(lowTraceId, timestamp); this.spansByTraceIdTimeStamp.put(traceIdTimeStamp, span); this.traceIdToTraceIdTimeStamps.put(lowTraceId, traceIdTimeStamp); ++this.acceptedSpanCount; if (this.searchEnabled) { String spanName = span.name(); if (span.localServiceName() != null) { this.serviceToTraceIds.put(span.localServiceName(), lowTraceId); if (spanName != null) { this.serviceToSpanNames.put(span.localServiceName(), spanName); } } if (span.remoteServiceName() != null) { this.serviceToTraceIds.put(span.remoteServiceName(), lowTraceId); if (spanName != null) { this.serviceToSpanNames.put(span.remoteServiceName(), spanName); } } } } return Call.create((Object)null); }

实际上，最终的span数据都是在这么几个对象中存在的

private final InMemoryStorage.SortedMultimap<InMemoryStorage.TraceIdTimestamp, Span> spansByTraceIdTimeStamp;private final InMemoryStorage.SortedMultimap<String, InMemoryStorage.TraceIdTimestamp> traceIdToTraceIdTimeStamps;private final InMemoryStorage.ServiceNameToTraceIds serviceToTraceIds;private final InMemoryStorage.SortedMultimap<String, String> serviceToSpanNames;

往期好文

[阅读源码的小技巧][Link 1]

[SpringBoot源码解析系列汇总][SpringBoot 1]

[Spring源码解析系列汇总][Spring]

[Eureka源码解析系列汇总][Eureka]

[SpringCloud服务调用源码解析汇总][SpringCloud]

[RabbitMQ系列汇总][RabbitMQ]

[SpringCloud基础系列汇总][SpringCloud 1]

[Redis系列汇总][Redis]

[MySQL系列汇总][MySQL]

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[SpringBoot]: https://blog.csdn.net/javaxuexilu/article/details/102481670
[Link 1]: http://mp.weixin.qq.com/s?__biz=MzU5MDgzOTYzMw%3D%3D&chksm=fe396ed1c94ee7c7eed78d1a492524c0fc0a0ee5497c9b016da7ce6ae0c2c0d393d0cbe20c26&idx=1&mid=2247484655&scene=21&sn=ea70de1cc2e7278bbed761780cb5241c#wechat_redirect
[SpringBoot 1]: https://blog.csdn.net/javaxuexilu/article/details/102481673
[Spring]: https://blog.csdn.net/javaxuexilu/article/details/100738704
[Eureka]: https://blog.csdn.net/javaxuexilu/article/details/102735465
[SpringCloud]: https://blog.csdn.net/javaxuexilu/article/details/102951570
[RabbitMQ]: https://blog.csdn.net/javaxuexilu/article/details/100738628
[SpringCloud 1]: http://mp.weixin.qq.com/s?__biz=MzU5MDgzOTYzMw%3D%3D&chksm=fe396840c94ee156adfcd44c63a3b5c1cf93805cf592ad7d45bc5222c349ba6f552b553a5c09&idx=1&mid=2247484030&scene=21&sn=7ad29239aca876e29155f5b1439281bb#wechat_redirect
[Redis]: http://mp.weixin.qq.com/s?__biz=MzU5MDgzOTYzMw%3D%3D&chksm=fe396932c94ee0248ce1527844d9664a01e29a43b11b1910aa415facdc569c82a63cb07e44cf&idx=1&mid=2247484172&scene=21&sn=cad78126f0367dbd67e0336b0b369b5d#wechat_redirect
[MySQL]: https://blog.csdn.net/javaxuexilu/article/details/100738604
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