扫码关注公众号:芋道源码

发送: 百事可乐
获取永久解锁本站全部文章的链接

《Dubbo 实现原理与源码解析 —— 精品合集》 《Netty 实现原理与源码解析 —— 精品合集》
《Spring 实现原理与源码解析 —— 精品合集》 《MyBatis 实现原理与源码解析 —— 精品合集》
《Spring MVC 实现原理与源码解析 —— 精品合集》 《数据库实体设计合集》
《Spring Boot 实现原理与源码解析 —— 精品合集》 《Java 面试题 + Java 学习指南》

摘要: 原创出处 https://blog.csdn.net/apei830/article/details/78722263 「v墨竹v」欢迎转载,保留摘要,谢谢!


🙂🙂🙂关注**微信公众号:【芋道源码】**有福利:

  1. RocketMQ / MyCAT / Sharding-JDBC 所有源码分析文章列表
  2. RocketMQ / MyCAT / Sharding-JDBC 中文注释源码 GitHub 地址
  3. 您对于源码的疑问每条留言将得到认真回复。甚至不知道如何读源码也可以请教噢
  4. 新的源码解析文章实时收到通知。每周更新一篇左右
  5. 认真的源码交流微信群。

前面花了大量篇幅来介绍Brave的使用,一直把Zipkin当黑盒在使用,现在来逐渐拨开Zipkin的神秘面纱。 Zipkin的源代码地址为:https://github.com/openzipkin/zipkin

Zipkin的源码结构 Zipkin的源码结构Zipkin的源码结构

  • zipkin - 对应的是zipkin v1
  • zipkin2 - 对应的是zipkin v2
  • zipkin-server - 是zipkin的web工程目录,zipkin.server.ZipkinServer是启动类
  • zipkin-ui - zipkin ui工程目录,zipkin的设计师前后端分离的,zipkin-server提供数据查询接口,zipkin-ui做数据展现。
  • zipkin-autoconfigure - 是为springboot提供的自动配置相关的类 collector-kafka collector-kafka10 collector-rabbitmq collector-scribe metrics-prometheus storage-cassandra storage-cassandra3 storage-elasticsearch-aws storage-elasticsearch-http storage-mysql ui
  • zipkin-collector - 是zipkin比较重要的模块,收集trace信息,支持从kafka和rabbitmq,以及scribe中收集,这个模块是可选的,因为zipkin默认使用http协议提供给客户端来收集 kafka kafka10 rabbitmq scribe
  • zipkin-storage - 也是zipkin比较重要的模块,用于存储收集的trace信息,默认是使用内置的InMemoryStorage,即存储在内存中,重启就会丢失。我们可以根据我们实际的需要更换存储方式,将trace存储在mysql,elasticsearch,cassandra中。 cassandra elasticsearch elasticsearch-http mysql zipkin2_cassandra

ZipkinServer

ZipkinServer是SpringBoot启动类,该类上使用了@EnableZipkinServer注解,加载了相关的Bean,而且在启动方法中添加了监听器RegisterZipkinHealthIndicators类,来初始化健康检查的相关bean。

@SpringBootApplication
@EnableZipkinServer
public class ZipkinServer {

public static void main(String[] args) {
new SpringApplicationBuilder(ZipkinServer.class)
.listeners(new RegisterZipkinHealthIndicators())
.properties("spring.config.name=zipkin-server").run(args);
}
}

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Import({
ZipkinServerConfiguration.class,
BraveConfiguration.class,
ZipkinQueryApiV1.class,
ZipkinHttpCollector.class
})
public @interface EnableZipkinServer {

}

EnableZipkinServer注解导入了ZipkinServerConfiguration,BraveConfiguration,ZipkinQueryApiV1,ZipkinHttpCollector。注意,这里并没有导入ZipkinQueryApiV2,但是由于SpringBoot项目会默认加载和启动类在一个包,或者在其子包的所有使用Component,Controller,Service等注解的类,所以在启动后,也会发现ZipkinQueryApiV2也被加载了。

  • ZipkinServerConfiguration - Zipkin Server端所有核心配置
  • BraveConfiguration - Zipkin存储trace信息时,还可以将自身的trace信息一起记录,这时就依赖Brave相关的类,都在这个类里配置
  • ZipkinQueryApiV1 - Zipkin V1版本的查询API都在这个Controller中
  • ZipkinQueryApiV2 - Zipkin V2版本的查询API都在这个Controller中
  • ZipkinHttpCollector - Zipkin默认的Collector使用http协议里收集Trace信息,客户端调用/api/v1/spans或/api/v2/spans来上报trace信息

ZipkinServerConfiguration

所有Zipkin服务需要的Bean都在这个类里进行配置

  • ZipkinHealthIndicator - Zipkin健康自检的类
  • CollectorSampler - Collector的采样率,默认100%采样,可以通过zipkin.collector.sample-rate来设置采样率
  • CollectorMetrics - Collector的统计信息,默认实现为ActuateCollectorMetrics
  • BraveTracedStorageComponentEnhancer - Zipkin存储trace时的self-trace类,启用后会将Zipkin的Storage存储模块执行的trace信息也采集进系统中
  • InMemoryConfiguration - 默认的内存Storage存储配置,当zipkin.storage.type属性未指定,或者容器中没有配置StorageComponent时,该配置被激活

ZipkinHealthIndicator

Zipkin健康自检的类,实现了springboot-actuate的CompositeHealthIndicator,提供系统组件的健康信息

final class ZipkinHealthIndicator extends CompositeHealthIndicator {

ZipkinHealthIndicator(HealthAggregator healthAggregator) {
super(healthAggregator);
}

void addComponent(Component component) {
String healthName = component instanceof V2StorageComponent
? ((V2StorageComponent) component).delegate().getClass().getSimpleName()
: component.getClass().getSimpleName();
healthName = healthName.replace("AutoValue_", "");
addHealthIndicator(healthName, new ComponentHealthIndicator(component));
}

static final class ComponentHealthIndicator implements HealthIndicator {
final Component component;

ComponentHealthIndicator(Component component) {
this.component = component;
}

@Override public Health health() {
Component.CheckResult result = component.check();
return result.ok ? Health.up().build() : Health.down(result.exception).build();
}
}
}

RegisterZipkinHealthIndicators

启动时加载的RegisterZipkinHealthIndicators类,当启动启动后,收到ApplicationReadyEvent事件,即系统已经启动完毕,会将Spring容器中的zipkin.Component添加到ZipkinHealthIndicator中

public final class RegisterZipkinHealthIndicators implements ApplicationListener {

@Override public void onApplicationEvent(ApplicationEvent event) {
if (!(event instanceof ApplicationReadyEvent)) return;
ConfigurableListableBeanFactory beanFactory =
((ApplicationReadyEvent) event).getApplicationContext().getBeanFactory();
ZipkinHealthIndicator healthIndicator = beanFactory.getBean(ZipkinHealthIndicator.class);
for (Component component : beanFactory.getBeansOfType(Component.class).values()) {
healthIndicator.addComponent(component);
}
}
}

启动zipkin,访问下面地址,可以看到输出zipkin的健康检查信息 http://localhost:9411/health.json

{"status":"UP","zipkin":{"status":"UP","InMemoryStorage":{"status":"UP"}},"diskSpace":{"status":"UP","total":429495595008,"free":392936411136,"threshold":10485760}}

ZipkinHttpCollector

Zipkin默认的Collector使用http协议里收集Trace信息,客户端均调用/api/v1/spans或/api/v2/spans来上报trace信息

@Autowired ZipkinHttpCollector(StorageComponent storage, CollectorSampler sampler,
CollectorMetrics metrics) {
this.metrics = metrics.forTransport("http");
this.collector = Collector.builder(getClass())
.storage(storage).sampler(sampler).metrics(this.metrics).build();
}

@RequestMapping(value = "/api/v2/spans", method = POST)
public ListenableFuture<ResponseEntity<?>> uploadSpansJson2(
@RequestHeader(value = "Content-Encoding", required = false) String encoding,
@RequestBody byte[] body
) {
return validateAndStoreSpans(encoding, JSON2_DECODER, body);
}

ListenableFuture<ResponseEntity<?>> validateAndStoreSpans(String encoding, SpanDecoder decoder,
byte[] body) {
SettableListenableFuture<ResponseEntity<?>> result = new SettableListenableFuture<>();
metrics.incrementMessages();
if (encoding != null && encoding.contains("gzip")) {
try {
body = gunzip(body);
} catch (IOException e) {
metrics.incrementMessagesDropped();
result.set(ResponseEntity.badRequest().body("Cannot gunzip spans: " + e.getMessage() + "\n"));
}
}
collector.acceptSpans(body, decoder, new Callback<Void>() {
@Override public void onSuccess(@Nullable Void value) {
result.set(SUCCESS);
}

@Override public void onError(Throwable t) {
String message = t.getMessage() == null ? t.getClass().getSimpleName() : t.getMessage();
result.set(t.getMessage() == null || message.startsWith("Cannot store")
? ResponseEntity.status(500).body(message + "\n")
: ResponseEntity.status(400).body(message + "\n"));
}
});
return result;
}

ZipkinHttpCollector中uploadSpansJson2方法接受所有/api/v2/spans请求,然后调用validateAndStoreSpans方法校验并存储Span 在validateAndStoreSpans方法中,当请求数据为gzip格式,会先解压缩,然后调用collector的acceptSpans方法

Collector

zipkin.collector.Collector的acceptSpans方法中,对各种格式的Span数据做了兼容处理,我们这里只看下V2版的JSON格式的Span是如何处理的,即会调用storage2(V2Collector)的acceptSpans方法

public class Collector
extends zipkin.internal.Collector<SpanDecoder, zipkin.Span> {
@Override
public void acceptSpans(byte[] serializedSpans, SpanDecoder decoder, Callback<Void> callback) {
try {
if (decoder instanceof DetectingSpanDecoder) decoder = detectFormat(serializedSpans);
} catch (RuntimeException e) {
metrics.incrementBytes(serializedSpans.length);
callback.onError(errorReading(e));
return;
}
if (storage2 != null && decoder instanceof V2JsonSpanDecoder) {
storage2.acceptSpans(serializedSpans, SpanBytesDecoder.JSON_V2, callback);
} else {
super.acceptSpans(serializedSpans, decoder, callback);
}
}
}

V2Collector

zipkin.internal.V2Collector继承了zipkin.internal.Collector,而在Collector的acceptSpans方法中会调用decodeList先将传入的二进制数据转换成Span对象,然后调用accept方法,accept方法中会调用sampled方法,将需要采样的Span过滤出来,最后调用record方法将Span信息存入Storage中。

public abstract class Collector<D, S> {
protected void acceptSpans(byte[] serializedSpans, D decoder, Callback<Void> callback) {
metrics.incrementBytes(serializedSpans.length);
List<S> spans;
try {
spans = decodeList(decoder, serializedSpans);
} catch (RuntimeException e) {
callback.onError(errorReading(e));
return;
}
accept(spans, callback);
}

public void accept(List<S> spans, Callback<Void> callback) {
if (spans.isEmpty()) {
callback.onSuccess(null);
return;
}
metrics.incrementSpans(spans.size());

List<S> sampled = sample(spans);
if (sampled.isEmpty()) {
callback.onSuccess(null);
return;
}

try {
record(sampled, acceptSpansCallback(sampled));
callback.onSuccess(null);
} catch (RuntimeException e) {
callback.onError(errorStoringSpans(sampled, e));
return;
}
}

List<S> sample(List<S> input) {
List<S> sampled = new ArrayList<>(input.size());
for (S s : input) {
if (isSampled(s)) sampled.add(s);
}
int dropped = input.size() - sampled.size();
if (dropped > 0) metrics.incrementSpansDropped(dropped);
return sampled;
}
}

V2Collector中的record方法会调用storage的accept方法,zipkin默认会使用InMemoryStorage来存储

public final class V2Collector extends Collector<BytesDecoder<Span>, Span> {
@Override protected List<Span> decodeList(BytesDecoder<Span> decoder, byte[] serialized) {
List<Span> out = new ArrayList<>();
if (!decoder.decodeList(serialized, out)) return Collections.emptyList();
return out;
}

@Override protected boolean isSampled(Span span) {
return sampler.isSampled(Util.lowerHexToUnsignedLong(span.traceId()), span.debug());
}

@Override protected void record(List<Span> sampled, Callback<Void> callback) {
storage.spanConsumer().accept(sampled).enqueue(new V2CallbackAdapter<>(callback));
}
}

ZipkinQueryApiV1 & ZipkinQueryApiV2

暴露了Zipkin对外的查询API,V1和V2的区别,主要是Span里的字段叫法不一样了,这里主要看下ZipkinQueryApiV2,ZipkinQueryApiV2方法都比较简单,主要是调用storage组件来实现查询功能。

/dependencies - 查看所有trace的依赖关系 /services - 查看所有的services /spans - 根据serviceName查询spans信息 /traces - 根据serviceName,spanName,annotationQuery,minDuration,maxDuration等来搜索traces信息 /trace/{traceIdHex} - 根据traceId查询某条trace信息

至此ZipkinServer的代码分析的差不多了,在后面博文中我们再具体分析各种Storage,和Collector的源代码。

666. 彩蛋

如果你对 Zipkin 感兴趣,欢迎加入我的知识星球一起交流。

知识星球

文章目录
  1. 1. ZipkinServer
  2. 2. ZipkinServerConfiguration
  3. 3. ZipkinHealthIndicator
  4. 4. RegisterZipkinHealthIndicators
  5. 5. ZipkinHttpCollector
  6. 6. Collector
  7. 7. V2Collector
  8. 8. ZipkinQueryApiV1 & ZipkinQueryApiV2
  • 666. 彩蛋