Java - Brave / Zipkin：当前跨度为空
Java - Brave / Zipkin: Current Span Null
关于 Java 应用程序的小问题，请使用 Brave / Zipkin 进行跟踪。
我有一段非常简单的代码（附上代码+maven pom，准备运行重现问题）
import io.netty.handler.logging.LogLevel;
import org.springframework.http.client.reactive.ReactorClientHttpConnector;
import org.springframework.web.reactive.function.BodyInserters;
import org.springframework.web.reactive.function.client.WebClient;
import reactor.netty.http.client.HttpClient;
import reactor.netty.transport.logging.AdvancedByteBufFormat;
import zipkin2.reporter.AsyncReporter;
import zipkin2.reporter.brave.ZipkinSpanHandler;
import zipkin2.reporter.urlconnection.URLConnectionSender;
import brave.Tracing;
import brave.opentracing.BraveTracer;
import java.util.Map;
public class QuestionApplication {
public static void main(String[] args) {
final var sender = URLConnectionSender.create("http://the-zipkin-instance.com:9411/api/v2/spans");
final var spanReporter = AsyncReporter.create(sender);
final var tracing = Tracing.newBuilder().localServiceName("thisIsTheClientApplicationWhoIsGeneratingTheFirstTraceId").addSpanHandler(ZipkinSpanHandler.create(spanReporter)).build();
final var tracer = BraveTracer.create(tracing).unwrap().tracer();
final var webClient = WebClient.create().mutate().clientConnector(new ReactorClientHttpConnector(HttpClient.create().wiretap("reactor.netty.http.client.HttpClient", LogLevel.INFO, AdvancedByteBufFormat.HEX_DUMP))).build();
final var jsonPayload = Map.of("key", "someKey", "value", "someValue");
final var span = tracer.currentSpan();
final var context = span.context();
final var traceIdString = context.traceIdString();
final var response = webClient.post().uri("http://the-server.com/api/route").header("X-B3-TraceId", traceIdString).body(BodyInserters.fromValue(jsonPayload)).retrieve().bodyToMono(String.class).block();
System.out.println(response);
}
}
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.github</groupId>
<artifactId>question</artifactId>
<version>1.1</version>
<properties>
<java.version>11</java.version>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
<version>2.5.4</version>
</dependency>
<dependency>
<groupId>io.zipkin.reporter2</groupId>
<artifactId>zipkin-sender-urlconnection</artifactId>
<version>2.16.3</version>
</dependency>
<dependency>
<groupId>io.opentracing.brave</groupId>
<artifactId>brave-opentracing</artifactId>
<version>1.0.0</version>
</dependency>
</dependencies>
</project>
在这里，使用上面的代码，我在行 final var context = span.context(); 上得到一个 java.lang.NullPointerException，因为跨度为空 final var span = tracer.currentSpan();
本应用为“客户端”应用，即最先发起http调用，因此，我希望这一小段主代码最先生成trace ID，trace ID会在十几分钟内运行其他子系统。
请问这是什么问题，这个 NPE 的根本原因是什么，或者我应该说，创建要传递的跟踪 ID 的正确方法是什么，因为我是链中的第一个？
谢谢
我不知道你的 NPE 生成了什么（技术上），但考虑到 Tracing 来自 Brave，SpanHandler 注入和 Brave 包装器很奇怪。那么最有可能的是，在这两行中，您没有为创建 Spans 注入必要的依赖项。
Tracing.newBuilder().localServiceName("thisIsTheClientApplicationWhoIsGeneratingTheFirstTraceId").addSpanHandler(ZipkinSpanHandler.create(spanReporter)).build();
BraveTracer.create(tracing).unwrap().tracer();
这里我做了一个没有这些行的例子，它按你预期的那样工作。使用 parent-child 流结构，您可以通过注入和提取 headers 的跟踪来复制和分发它在其组件中：X-B3-TraceId、X-B3-ParentSpanId、X-B3-SpanId , X-B3-采样。
主要代码
package com.Whosebug.q69430794;
import brave.Span;
import brave.Tracing;
import zipkin2.reporter.AsyncReporter;
import zipkin2.reporter.okhttp3.OkHttpSender;
public class QuestionApplication {
public static void main(String[] args) {
var sender = OkHttpSender.newBuilder().endpoint("http://localhost:9411/api/v2/spans").build();
var reporter = AsyncReporter.builder(sender).build();
var tracing = Tracing.newBuilder().localServiceName("component-test").spanReporter(reporter).build();
// Create parent span and his child --------------------
// Parent
tracing.tracer().startScopedSpan("parentSpan");
Span span = tracing.tracer().currentSpan();
span.tag("key", "firstBiz");
// Child
tracing.tracer().startScopedSpanWithParent("childSpan", tracing.tracer().currentSpan().context());
Span childSpan = tracing.tracer().currentSpan();
childSpan.tag("key", "secondBiz");
childSpan.finish();
System.out.println("id:" + childSpan.context().traceIdString());
// Finish span
span.finish();
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// -----------------------------------------------------
}
}
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.Whosebug.q69430794</groupId>
<artifactId>69430794</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>69430794</name>
<description>Question # 69430794</description>
<properties>
<java.version>11</java.version>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
<version>2.5.4</version>
</dependency>
<dependency>
<groupId>io.zipkin.brave</groupId>
<artifactId>brave</artifactId>
<version>5.4.2</version>
</dependency>
<dependency>
<groupId>io.zipkin.reporter2</groupId>
<artifactId>zipkin-sender-okhttp3</artifactId>
<version>2.7.9</version>
</dependency>
</dependencies>
</project>
我用了docker 图片：
docker pull openzipkin/zipkin
关于 Java 应用程序的小问题，请使用 Brave / Zipkin 进行跟踪。
我有一段非常简单的代码（附上代码+maven pom，准备运行重现问题）
import io.netty.handler.logging.LogLevel;
import org.springframework.http.client.reactive.ReactorClientHttpConnector;
import org.springframework.web.reactive.function.BodyInserters;
import org.springframework.web.reactive.function.client.WebClient;
import reactor.netty.http.client.HttpClient;
import reactor.netty.transport.logging.AdvancedByteBufFormat;
import zipkin2.reporter.AsyncReporter;
import zipkin2.reporter.brave.ZipkinSpanHandler;
import zipkin2.reporter.urlconnection.URLConnectionSender;
import brave.Tracing;
import brave.opentracing.BraveTracer;
import java.util.Map;
public class QuestionApplication {
public static void main(String[] args) {
final var sender = URLConnectionSender.create("http://the-zipkin-instance.com:9411/api/v2/spans");
final var spanReporter = AsyncReporter.create(sender);
final var tracing = Tracing.newBuilder().localServiceName("thisIsTheClientApplicationWhoIsGeneratingTheFirstTraceId").addSpanHandler(ZipkinSpanHandler.create(spanReporter)).build();
final var tracer = BraveTracer.create(tracing).unwrap().tracer();
final var webClient = WebClient.create().mutate().clientConnector(new ReactorClientHttpConnector(HttpClient.create().wiretap("reactor.netty.http.client.HttpClient", LogLevel.INFO, AdvancedByteBufFormat.HEX_DUMP))).build();
final var jsonPayload = Map.of("key", "someKey", "value", "someValue");
final var span = tracer.currentSpan();
final var context = span.context();
final var traceIdString = context.traceIdString();
final var response = webClient.post().uri("http://the-server.com/api/route").header("X-B3-TraceId", traceIdString).body(BodyInserters.fromValue(jsonPayload)).retrieve().bodyToMono(String.class).block();
System.out.println(response);
}
}
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.github</groupId>
<artifactId>question</artifactId>
<version>1.1</version>
<properties>
<java.version>11</java.version>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
<version>2.5.4</version>
</dependency>
<dependency>
<groupId>io.zipkin.reporter2</groupId>
<artifactId>zipkin-sender-urlconnection</artifactId>
<version>2.16.3</version>
</dependency>
<dependency>
<groupId>io.opentracing.brave</groupId>
<artifactId>brave-opentracing</artifactId>
<version>1.0.0</version>
</dependency>
</dependencies>
</project>
在这里，使用上面的代码，我在行 final var context = span.context(); 上得到一个 java.lang.NullPointerException，因为跨度为空 final var span = tracer.currentSpan();
本应用为“客户端”应用，即最先发起http调用，因此，我希望这一小段主代码最先生成trace ID，trace ID会在十几分钟内运行其他子系统。
请问这是什么问题，这个 NPE 的根本原因是什么，或者我应该说，创建要传递的跟踪 ID 的正确方法是什么，因为我是链中的第一个？
谢谢
我不知道你的 NPE 生成了什么（技术上），但考虑到 Tracing 来自 Brave，SpanHandler 注入和 Brave 包装器很奇怪。那么最有可能的是，在这两行中，您没有为创建 Spans 注入必要的依赖项。
Tracing.newBuilder().localServiceName("thisIsTheClientApplicationWhoIsGeneratingTheFirstTraceId").addSpanHandler(ZipkinSpanHandler.create(spanReporter)).build();
BraveTracer.create(tracing).unwrap().tracer();
这里我做了一个没有这些行的例子，它按你预期的那样工作。使用 parent-child 流结构，您可以通过注入和提取 headers 的跟踪来复制和分发它在其组件中：X-B3-TraceId、X-B3-ParentSpanId、X-B3-SpanId , X-B3-采样。
主要代码
package com.Whosebug.q69430794;
import brave.Span;
import brave.Tracing;
import zipkin2.reporter.AsyncReporter;
import zipkin2.reporter.okhttp3.OkHttpSender;
public class QuestionApplication {
public static void main(String[] args) {
var sender = OkHttpSender.newBuilder().endpoint("http://localhost:9411/api/v2/spans").build();
var reporter = AsyncReporter.builder(sender).build();
var tracing = Tracing.newBuilder().localServiceName("component-test").spanReporter(reporter).build();
// Create parent span and his child --------------------
// Parent
tracing.tracer().startScopedSpan("parentSpan");
Span span = tracing.tracer().currentSpan();
span.tag("key", "firstBiz");
// Child
tracing.tracer().startScopedSpanWithParent("childSpan", tracing.tracer().currentSpan().context());
Span childSpan = tracing.tracer().currentSpan();
childSpan.tag("key", "secondBiz");
childSpan.finish();
System.out.println("id:" + childSpan.context().traceIdString());
// Finish span
span.finish();
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// -----------------------------------------------------
}
}
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.Whosebug.q69430794</groupId>
<artifactId>69430794</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>69430794</name>
<description>Question # 69430794</description>
<properties>
<java.version>11</java.version>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
<version>2.5.4</version>
</dependency>
<dependency>
<groupId>io.zipkin.brave</groupId>
<artifactId>brave</artifactId>
<version>5.4.2</version>
</dependency>
<dependency>
<groupId>io.zipkin.reporter2</groupId>
<artifactId>zipkin-sender-okhttp3</artifactId>
<version>2.7.9</version>
</dependency>
</dependencies>
</project>
我用了docker 图片：
docker pull openzipkin/zipkin
