add helper funcs

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

kgo.go

@@ -73,6 +73,10 @@ func (k *Broker) Name() string {
 	return k.opts.Name
 }
 
+func (k *Broker) Client() *kgo.Client {
+	return k.c
+}
+
 func (k *Broker) connect(ctx context.Context, opts ...kgo.Opt) (*kgo.Client, *hookTracer, error) {
 	var c *kgo.Client
 	var err error
@@ -322,6 +326,22 @@ func (k *Broker) publish(ctx context.Context, msgs []*broker.Message, opts ...br
 	return nil
 }
 
+func (k *Broker) TopicExists(ctx context.Context, topic string) error {
+	mdreq := kmsg.NewMetadataRequest()
+	mdreq.Topics = []kmsg.MetadataRequestTopic{
+		{Topic: &topic},
+	}
+
+	mdrsp, err := mdreq.RequestWith(ctx, k.c)
+	if err != nil {
+		return err
+	} else if mdrsp.Topics[0].ErrorCode != 0 {
+		return fmt.Errorf("topic %s not exists or permission error", topic)
+	}
+
+	return nil
+}
+
 func (k *Broker) BatchSubscribe(ctx context.Context, topic string, handler broker.BatchHandler, opts ...broker.SubscribeOption) (broker.Subscriber, error) {
 	return nil, nil
 }

subscriber.go

@@ -46,6 +46,10 @@ type subscriber struct {
 	sync.RWMutex
 }
 
+func (s *subscriber) Client() *kgo.Client {
+	return s.c
+}
+
 func (s *subscriber) Options() broker.SubscribeOptions {
 	return s.opts
 }

tracer.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/twmb/franz-go/pkg/kgo"
 	semconv "go.opentelemetry.io/otel/semconv/v1.18.0"
+	"go.unistack.org/micro/v3/metadata"
 	"go.unistack.org/micro/v3/tracer"
 )
 
@@ -44,8 +45,21 @@ func (m *hookTracer) OnProduceRecordBuffered(r *kgo.Record) {
 		tracer.WithSpanLabels(attrs...),
 		tracer.WithSpanKind(tracer.SpanKindProducer),
 	}
+
+	if r.Context == nil {
+		r.Context = context.Background()
+	}
+
+	md, ok := metadata.FromOutgoingContext(r.Context)
+	if !ok {
+		md = metadata.New(len(r.Headers))
+	}
+	for _, h := range r.Headers {
+		md.Set(h.Key, string(h.Value))
+	}
+
 	// Start the "publish" span.
-	ctx, _ := m.tracer.Start(r.Context, r.Topic+" publish", opts...)
+	ctx, _ := m.tracer.Start(metadata.NewOutgoingContext(r.Context, md), r.Topic+" publish", opts...)
 	// Inject the span context into the record.
 	// t.propagators.Inject(ctx, NewRecordCarrier(r))
 	// Update the record context.
@@ -99,10 +113,18 @@ func (m *hookTracer) OnFetchRecordBuffered(r *kgo.Record) {
 	if r.Context == nil {
 		r.Context = context.Background()
 	}
+	md, ok := metadata.FromIncomingContext(r.Context)
+	if !ok {
+		md = metadata.New(len(r.Headers))
+	}
+	for _, h := range r.Headers {
+		md.Set(h.Key, string(h.Value))
+	}
+
 	// Extract the span context from the record.
 	// ctx := t.propagators.Extract(r.Context, NewRecordCarrier(r))
 	// Start the "receive" span.
-	newCtx, _ := m.tracer.Start(r.Context, r.Topic+" receive", opts...)
+	newCtx, _ := m.tracer.Start(metadata.NewIncomingContext(r.Context, md), r.Topic+" receive", opts...)
 	// Update the record context.
 	r.Context = newCtx
 }
@@ -148,6 +170,14 @@ func (m *hookTracer) WithProcessSpan(r *kgo.Record) (context.Context, tracer.Spa
 	if r.Context == nil {
 		r.Context = context.Background()
 	}
+	md, ok := metadata.FromIncomingContext(r.Context)
+	if !ok {
+		md = metadata.New(len(r.Headers))
+	}
+	for _, h := range r.Headers {
+		md.Set(h.Key, string(h.Value))
+	}
+
 	// Start a new span using the provided context and options.
 	return m.tracer.Start(r.Context, r.Topic+" process", opts...)
 }