Fix opentracing.Bridge where it miss identifying the spanKind

bridge/opentracing/bridge.go

@@ -18,7 +18,6 @@ import (
 	"context"
 	"fmt"
 	"net/http"
-	"strings"
 	"sync"
 
 	ot "github.com/opentracing/opentracing-go"
@@ -502,17 +501,15 @@ func otTagsToOTelAttributesKindAndError(tags map[string]interface{}) ([]attribut
 	for k, v := range tags {
 		switch k {
 		case string(otext.SpanKind):
-			if s, ok := v.(string); ok {
-				switch strings.ToLower(s) {
-				case "client":
-					kind = trace.SpanKindClient
-				case "server":
-					kind = trace.SpanKindServer
-				case "producer":
-					kind = trace.SpanKindProducer
-				case "consumer":
-					kind = trace.SpanKindConsumer
-				}
+			switch v {
+			case otext.SpanKindRPCClientEnum:
+				kind = trace.SpanKindClient
+			case otext.SpanKindRPCServerEnum:
+				kind = trace.SpanKindServer
+			case otext.SpanKindProducerEnum:
+				kind = trace.SpanKindProducer
+			case otext.SpanKindConsumerEnum:
+				kind = trace.SpanKindConsumer
 			}
 		case string(otext.Error):
 			if b, ok := v.(bool); ok && b {

bridge/opentracing/bridge_test.go

@@ -22,7 +22,9 @@ import (
 	"testing"
 
 	ot "github.com/opentracing/opentracing-go"
+	"github.com/opentracing/opentracing-go/ext"
 	"github.com/stretchr/testify/assert"
+	"go.opentelemetry.io/otel/bridge/opentracing/internal"
 
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/propagation"
@@ -425,3 +427,34 @@ func TestBridgeTracer_StartSpan(t *testing.T) {
 		})
 	}
 }
+
+func Test_otTagsToOTelAttributesKindAndError(t *testing.T) {
+	tracer := internal.NewMockTracer()
+	sc := &bridgeSpanContext{}
+
+	testCases := []struct {
+		name     string
+		opt      []ot.StartSpanOption
+		expected trace.SpanKind
+	}{
+		{
+			name:     "client",
+			opt:      []ot.StartSpanOption{ext.SpanKindRPCClient},
+			expected: trace.SpanKindClient,
+		},
+		{
+			name:     "server",
+			opt:      []ot.StartSpanOption{ext.RPCServerOption(sc)},
+			expected: trace.SpanKindServer,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			b, _ := NewTracerPair(tracer)
+
+			s := b.StartSpan(tc.name, tc.opt...)
+			assert.Equal(t, s.(*bridgeSpan).otelSpan.(*internal.MockSpan).SpanKind, tc.expected)
+		})
+	}
+}