如何从字符串traceid创建opentelemetry跨度

Question

我知道我们将使用上下文传播来获取作为彼此的子级创建的父跟踪和跨度，但我的发布者正在使用标头（nats不是超文本传输协议）

我的message broker使用标头，我正在将traceid和spanid设置为出站请求中的标头，并发送消息，然后订阅者应该能够创建一个新的span，将父traceid设置为请求中的traceid。链接它们

我的出站请求如下所示：

        msg := new(nats.Msg)
        msg.Data = []byte("new request being sent!")
        msg.Subject = subject
        getTraceID := requestSpan.SpanContext().TraceID().String()
        header := make(nats.Header)
        msg.Header = header
        header.Set("traceid", getTraceID)

        getSpanID := requestSpan.SpanContext().SpanID().String(
        header.Set("spanid", getSpanID)
        msg.Header = header
        
        reply, err := nc.RequestMsg(msg, time.Duration(5*time.Second))

这可以工作，在订阅者端，我可以获取跟踪和跨度ID的标头值

如何使用traceid在订阅者端构建上下文/span？

我相信我可以在通道内做这样的事情：

    var traceID trace.TraceID
    traceID, err = trace.TraceIDFromHex(request.TraceID)
    if err != nil {
        fmt.Println("error: ", err)
        continue
    }
    var spanID trace.SpanID
    spanID, err = trace.SpanIDFromHex(request.SpanID)
    if err != nil {
        fmt.Println("error: ", err)
        continue
    }

    spanContext := trace.NewSpanContext(trace.SpanContextConfig{
        TraceID:    traceID,
        SpanID:     spanID,
        TraceFlags: 01, 
    })

   ctx := context.Background()
   ctx = trace.ContextWithSpanContext(ctx, spanContext)
   var requestInLoopSpan trace.Span
   ctx2, requestInLoopSpan := otel.Tracer("requestInLoop").Start(ctx, "requestInLoopSpan")

   requestInLoopSpan.AddEvent("processing....") // NOT WORKING

Answer 1

拿到了！

btw类型NewRequest：

type NewRequest struct {
    Requestid    string `json: "requestid"`
    TraceID      string
    SpanID       string
}

您需要将构建spanContext的代码包装到函数中：

func constructNewSpanContext(request NewRequest) (spanContext trace.SpanContext, err error) {
    var traceID trace.TraceID
    traceID, err = trace.TraceIDFromHex(request.TraceID)
    if err != nil {
        fmt.Println("error: ", err)
        return spanContext, err
    }
    var spanID trace.SpanID
    spanID, err = trace.SpanIDFromHex(request.SpanID)
    if err != nil {
        fmt.Println("error: ", err)
        return spanContext, err
    }
    var spanContextConfig trace.SpanContextConfig
    spanContextConfig.TraceID = traceID
    spanContextConfig.SpanID = spanID
    spanContextConfig.TraceFlags = 01
    spanContextConfig.Remote = false
    spanContext = trace.NewSpanContext(spanContextConfig)
    return spanContext, nil
}

然后你称之为传递包含痕迹和跨度标识的东西

然后使用函数返回的spanContext来丰富上下文：

        spanContext, err := constructNewSpanContext(request)
        if err != nil {
            fmt.Println("ERROR: ", err)
        }
        fmt.Println("IS VALID? ", spanContext.IsValid()) // check if okay

        requestContext := context.Background()
        requestContext = trace.ContextWithSpanContext(requestContext, spanContext)

        var requestInLoopSpan trace.Span
        childContext, requestInLoopSpan := otel.Tracer("inboundmessage").Start(requestContext, "requestInLoopSpan")
        requestInLoopSpan.AddEvent("processing....") // WORKING