原 荐 Dubbo + Zipkin + Brave实现全链路追踪

Dubbo + Zipkin + Brave实现全链路追踪

最近写了一个链路追踪Demo分享下，实现了链路追踪过程中数据的记录，还有能扩展的地方，后期再继续补充。

原理参考上面文章 《Dubbo链路追踪——生成全局ID（traceId）》

源码地址

分布式跟踪系统还有其他比较成熟的实现，例如：Naver的Pinpoint、Apache的HTrace、阿里的鹰眼Tracing、京东的Hydra、新浪的Watchman，美团点评的CAT，skywalking等。 本次主要利用Dubbo数据传播特性扩展Filter接口来实现链路追踪的目的

重点主要是zipkin及brave使用及特性,当前brave版本为 5.2.0 为 2018年8月份发布的release版本 , zipkin版本为2.2.1 所需JDK为1.8

快速启动zipkin

下载最新的zipkin并启动

wget -O zipkin.jar 'https://search.maven.org/remote_content?g=io.zipkin.java&a=zipkin-server&v=LATEST&c=exec'
java -jar zipkin.jar

输入 http://localhost:9411/zipkin/ 进入WebUI界面如下

核心源码

代码的初步版本：方便描述

import brave.Span;
import brave.Tracer;
import brave.Tracing;
import brave.propagation.*;
import brave.sampler.Sampler;
import com.alibaba.dubbo.common.Constants;
import com.alibaba.dubbo.common.extension.Activate;
import com.alibaba.dubbo.common.json.JSON;
import com.alibaba.dubbo.common.logger.Logger;
import com.alibaba.dubbo.common.logger.LoggerFactory;
import com.alibaba.dubbo.remoting.exchange.ResponseCallback;
import com.alibaba.dubbo.rpc.*;
import com.alibaba.dubbo.rpc.protocol.dubbo.FutureAdapter;
import com.alibaba.dubbo.rpc.support.RpcUtils;
import zipkin2.codec.SpanBytesEncoder;
import zipkin2.reporter.AsyncReporter;
import zipkin2.reporter.Sender;
import zipkin2.reporter.okhttp3.OkHttpSender;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.util.Map;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

/**
 * Created with IntelliJ IDEA.
 *
 * @author: bakerZhu
 * @description:
 * @modifytime:
 */
@Activate(group = {Constants.PROVIDER, Constants.CONSUMER})
public class TracingFilter  implements Filter {

	private static final Logger log = LoggerFactory.getLogger(TracingFilter.class);

	private static Tracing tracing;
	private static Tracer tracer;
	private static TraceContext.Extractor<Map<String, String>> extractor;
	private static TraceContext.Injector<Map<String, String>> injector;

	static final Propagation.Getter<Map<String, String>, String> GETTER =
			new Propagation.Getter<Map<String, String>, String>() {
				@Override
				public String get(Map<String, String> carrier, String key) {
					return carrier.get(key);
				}

				@Override
				public String toString() {
					return "Map::get";
				}
			};

	static final Propagation.Setter<Map<String, String>, String> SETTER =
			new Propagation.Setter<Map<String, String>, String>() {
				@Override
				public void put(Map<String, String> carrier, String key, String value) {
					carrier.put(key, value);
				}

				@Override
				public String toString() {
					return "Map::set";
				}
			};

	static {
		// 1
		Sender sender = OkHttpSender.create("http://localhost:9411/api/v2/spans");
		// 2
		AsyncReporter asyncReporter = AsyncReporter.builder(sender)
				.closeTimeout(500, TimeUnit.MILLISECONDS)
				.build(SpanBytesEncoder.JSON_V2);
		// 3
		tracing = Tracing.newBuilder()
				.localServiceName("tracer-client")
				.spanReporter(asyncReporter)
				.sampler(Sampler.ALWAYS_SAMPLE)
				.propagationFactory(ExtraFieldPropagation.newFactory(B3Propagation.FACTORY, "user-name"))
				.build();
		tracer = tracing.tracer();
		// 4
		// 4.1
		extractor = tracing.propagation().extractor(GETTER);
		// 4.2
		injector = tracing.propagation().injector(SETTER);
	}



	public TracingFilter() {
	}

	@Override
	public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {


		RpcContext rpcContext = RpcContext.getContext();
		// 5
		Span.Kind kind = rpcContext.isProviderSide() ? Span.Kind.SERVER : Span.Kind.CLIENT;
		final Span span;
		if (kind.equals(Span.Kind.CLIENT)) {
			//6
			span = tracer.nextSpan();
			//7
			injector.inject(span.context(), invocation.getAttachments());
		} else {
			//8
			TraceContextOrSamplingFlags extracted = extractor.extract(invocation.getAttachments());
			//9
			span = extracted.context() != null ? tracer.joinSpan(extracted.context()) : tracer.nextSpan(extracted);
		}

		if (!span.isNoop()) {
			span.kind(kind).start();
			//10
			String service = invoker.getInterface().getSimpleName();
			String method = RpcUtils.getMethodName(invocation);
			span.kind(kind);
			span.name(service + "/" + method);
			InetSocketAddress remoteAddress = rpcContext.getRemoteAddress();
			span.remoteIpAndPort(
					remoteAddress.getAddress() != null ? remoteAddress.getAddress().getHostAddress() : remoteAddress.getHostName(),remoteAddress.getPort());
		}

		boolean isOneway = false, deferFinish = false;
		try (Tracer.SpanInScope scope = tracer.withSpanInScope(span)){
			//11
			collectArguments(invocation, span, kind);
			Result result = invoker.invoke(invocation);

			if (result.hasException()) {
				onError(result.getException(), span);
			}
			// 12
			isOneway = RpcUtils.isOneway(invoker.getUrl(), invocation);
			// 13
			Future<Object> future = rpcContext.getFuture();

			if (future instanceof FutureAdapter) {
				deferFinish = true;
				((FutureAdapter) future).getFuture().setCallback(new FinishSpanCallback(span));// 14
			}
			return result;
		} catch (Error | RuntimeException e) {
			onError(e, span);
			throw e;
		} finally {
			if (isOneway) { // 15
				span.flush();
			} else if (!deferFinish) { // 16
				span.finish();
			}
		}
	}

	static void onError(Throwable error, Span span) {
		span.error(error);
		if (error instanceof RpcException) {
			span.tag("dubbo.error_msg", RpcExceptionEnum.getMsgByCode(((RpcException) error).getCode()));
		}
	}

	static void collectArguments(Invocation invocation, Span span, Span.Kind kind) {
		if (kind == Span.Kind.CLIENT) {
			StringBuilder fqcn = new StringBuilder();
			Object[] args = invocation.getArguments();
			if (args != null && args.length > 0) {
				try {
					fqcn.append(JSON.json(args));
				} catch (IOException e) {
					log.warn(e.getMessage(), e);
				}
			}
			span.tag("args", fqcn.toString());
		}
	}



	static final class FinishSpanCallback implements ResponseCallback {
		final Span span;

		FinishSpanCallback(Span span) {
			this.span = span;
		}

		@Override
		public void done(Object response) {
			span.finish();
		}

		@Override
		public void caught(Throwable exception) {
			onError(exception, span);
			span.finish();
		}
	}
	// 17
	private enum RpcExceptionEnum {
		UNKNOWN_EXCEPTION(0, "unknown exception"),
		NETWORK_EXCEPTION(1, "network exception"),
		TIMEOUT_EXCEPTION(2, "timeout exception"),
		BIZ_EXCEPTION(3, "biz exception"),
		FORBIDDEN_EXCEPTION(4, "forbidden exception"),
		SERIALIZATION_EXCEPTION(5, "serialization exception"),;

		private int code;

		private String msg;

		RpcExceptionEnum(int code, String msg) {
			this.code = code;
			this.msg = msg;
		}

		public static String getMsgByCode(int code) {
			for (RpcExceptionEnum error : RpcExceptionEnum.values()) {
				if (code == error.code) {
					return error.msg;
				}
			}
			return null;
		}
	}
}

1. 构建客户端发送工具
2. 构建异步reporter
3. 构建tracing上下文
4. 初始化injector 和 Extractor [tab]4.1 extractor 指数据提取对象,用于在carrier中提取TraceContext相关信息或者采样标记信息到TraceContextOrSamplingFlags 中 -4.2 injector 用于将TraceContext中的各种数据注入到carrier中,其中carrier一半是指数据传输中的载体,类似于Dubbo中Invocation中的attachment(附件集合)
5. 判断此次调用是作为服务端还是客户端
6. rpc客户端调用会从ThreadLocal中获取parent的 TraceContext ,为新生成的Span指定traceId及 parentId如果没有parent traceContext 则生成的Span为 root span
7. 将Span绑定的TraceContext中 属性信息 Copy 到 Invocation中达到远程参数传递的作用
8. rpc服务提供端 , 从invocation中提取TraceContext相关信息及采样数据信息
9. 生成span , 兼容初次服务端调用
10. 记录接口信息及远程IP Port
11. 将创建的Span 作为当前Span (可以通过Tracer.currentSpan 访问到它) 并设置查询范围
12. oneway调用即只请求不接受结果
13. 如果future不为空则为 async 调用 在回调中finish span
14. 设置异步回调，回调代码执行span finish() .
15. oneway调用 因为不需等待返回值 即没有 cr (Client Receive) 需手动flush()
16. 同步调用 业务代码执行完毕后需手动finish()
17. 设置枚举类 与 Dubbo中RpcException保持对应

配置方式

POM依赖添加

<dependency>
    <groupId>com.github.baker</groupId>
    <artifactId>Tracing</artifactId>
    <version>1.0-SNAPSHOT</version>
</dependency>

资源目录根路径下添加tracing.properties文件 一次调用信息 调用链 调用成功失败汇总 zipkinHost 指定zipkin服务器IP:PORT 默认为localhost:9411 serviceName 指定应用名称 默认为trace-default

调用链：

源码地址