go-kratos/kratos · error

unsupported span kind: %v

Error message

unsupported span kind: %v

What it means

Error "unsupported span kind: %v" thrown in go-kratos/kratos.

Source

Thrown at contrib/otel/tracing/tracer.go:43

func NewTracer(kind trace.SpanKind, opts ...Option) *Tracer {
	op := options{
		propagator: propagation.NewCompositeTextMapPropagator(Metadata{}, propagation.Baggage{}, propagation.TraceContext{}),
		tracerName: "kratos",
	}
	for _, o := range opts {
		o(&op)
	}
	if op.tracerProvider == nil {
		op.tracerProvider = otel.GetTracerProvider()
	}

	switch kind {
	case trace.SpanKindClient:
		return &Tracer{tracer: op.tracerProvider.Tracer(op.tracerName), kind: kind, opt: &op}
	case trace.SpanKindServer:
		return &Tracer{tracer: op.tracerProvider.Tracer(op.tracerName), kind: kind, opt: &op}
	default:
		panic(fmt.Sprintf("unsupported span kind: %v", kind))
	}
}

// Start start tracing span
func (t *Tracer) Start(ctx context.Context, operation string, carrier propagation.TextMapCarrier) (context.Context, trace.Span) {
	if t.kind == trace.SpanKindServer {
		ctx = t.opt.propagator.Extract(ctx, carrier)
	}
	ctx, span := t.tracer.Start(ctx,
		operation,
		trace.WithSpanKind(t.kind),
	)
	if t.kind == trace.SpanKindClient {
		t.opt.propagator.Inject(ctx, carrier)
	}
	return ctx, span
}

View on GitHub (pinned to 668db92c2c)

When it happens

Trigger: Thrown at contrib/otel/tracing/tracer.go:43 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of go-kratos/kratos@668db92c2c (2026-08-16). Data as JSON: /api/errors/d2f3a4454c3a85f1. Report an issue: GitHub.