To ensure traces are not split across goroutine boundaries, you must propagate the trace context. //dd:span annotated functions handle context propagation based on their arguments:
context.Context: If the function accepts a context.Context argument, that context is used for trace propagation.*http.Request: If the function accepts a *http.Request argument, the request's context is used.- Fallback: If neither is present, the function relies on goroutine local storage, which means traces may split when starting new goroutines unless the context is explicitly passed.
To weave context into a child goroutine, pass the context.Context through the function call.
package demo
//dd:span
func caller(ctx context.Context) {
wait := make(chan struct{}, 1)
defer close(wait)
// Weaving the span context into the child goroutine by passing ctx
go callee(ctx, wait)
<-wait
}
//dd:span
func callee(ctx context.Context, done chan<- struct{}) {
done <- struct{}{}
}
