OpenTelemetry笔记(3)-Span关系

发表于 更新于

介绍 Span 的嵌套、传播、链接关系

Span 嵌套

通过 setParent 方法 Span 的上下文环境

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void parentOne() {
    Span parentSpan = tracer.spanBuilder("parent").startSpan();
    try {
        childOne(parentSpan);
    } finally {
        parentSpan.end();
    }
}

void childOne(Span parentSpan) {
    Span childSpan = tracer.spanBuilder("child")
        .setParent(Context.current().with(parentSpan))
        .startSpan();
    try {
        // do stuff
    } finally {
        childSpan.end();
    }
}

Span 传播(propagate)

通过调用 makeCurrent 方法,将 Span 传播为当前上下文

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void parentTwo() {
  Span parentSpan = tracer.spanBuilder("parent").startSpan();
  try(Scope scope = parentSpan.makeCurrent()) {
    childTwo();
  } finally {
    parentSpan.end();
  }
}
void childTwo() {
  Span childSpan = tracer.spanBuilder("child")
    // NOTE: setParent(...) is not required;
    // `Span.current()` is automatically added as the parent
    .startSpan();
  try(Scope scope = childSpan.makeCurrent()) {
    // do stuff
  } finally {
    childSpan.end();
  }
}

获取当前 Span

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//获取当前上下文的Span
Span span = Span.current();
//根据环境上下文获取Span
Span span = Span.fromContext(context);

Span 链接(SpanLink)

用于表示 Span 之间的关联关系，如下代码，两个 span 存在关联关系，但不是嵌套关系

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void parentOne() {
    Span parentSpan = tracer.spanBuilder("parent").startSpan();
    try {
        childOne(parentSpan);
    } finally {
        parentSpan.end();
    }
}

void childOne(Span parentSpan) {
    Span testSpan=tracer.spanBuilder("test").startSpan();
    Span childSpan = tracer.spanBuilder("child")
        .addLink(parentSpan.getSpanContext())
        .addLink(testSpan.getSpanContext())
        .startSpan();
    testSpan.end();
    try {
        // do stuff
    } finally {
        childSpan.end();
    }
}