ddtrace/opentracer: translate Datadog errors to OpenTracing errors

ddtrace/opentracer/tracer.go

@@ -73,7 +73,7 @@ func (t *opentracer) Inject(ctx opentracing.SpanContext, format interface{}, car
 	}
 	switch format {
 	case opentracing.TextMap, opentracing.HTTPHeaders:
-		return t.Tracer.Inject(sctx, carrier)
+		return translateError(t.Tracer.Inject(sctx, carrier))
 	default:
 		return opentracing.ErrUnsupportedFormat
 	}
@@ -83,7 +83,8 @@ func (t *opentracer) Inject(ctx opentracing.SpanContext, format interface{}, car
 func (t *opentracer) Extract(format interface{}, carrier interface{}) (opentracing.SpanContext, error) {
 	switch format {
 	case opentracing.TextMap, opentracing.HTTPHeaders:
-		return t.Tracer.Extract(carrier)
+		sctx, err := t.Tracer.Extract(carrier)
+		return sctx, translateError(err)
 	default:
 		return nil, opentracing.ErrUnsupportedFormat
 	}
@@ -99,3 +100,18 @@ func (t *opentracer) ContextWithSpanHook(ctx context.Context, openSpan opentraci
 	}
 	return tracer.ContextWithSpan(ctx, ddSpan.Span)
 }
+
+func translateError(err error) error {
+	switch err {
+	case tracer.ErrSpanContextNotFound:
+		return opentracing.ErrSpanContextNotFound
+	case tracer.ErrInvalidCarrier:
+		return opentracing.ErrInvalidCarrier
+	case tracer.ErrInvalidSpanContext:
+		return opentracing.ErrInvalidSpanContext
+	case tracer.ErrSpanContextCorrupted:
+		return opentracing.ErrSpanContextCorrupted
+	default:
+		return err
+	}
+}

ddtrace/opentracer/tracer_test.go

@@ -37,3 +37,77 @@ func TestSpanWithContext(t *testing.T) {
 	assert.True(ok)
 	assert.Equal(got, want.(*span).Span)
 }
+
+func TestInjectError(t *testing.T) {
+	ot := New()
+
+	for name, tt := range map[string]struct {
+		spanContext opentracing.SpanContext
+		format      interface{}
+		carrier     interface{}
+		want        error
+	}{
+		"ErrInvalidSpanContext": {
+			spanContext: internal.NoopSpanContext{},
+			format:      opentracing.TextMap,
+			carrier:     opentracing.TextMapCarrier(map[string]string{}),
+			want:        opentracing.ErrInvalidSpanContext,
+		},
+		"ErrInvalidCarrier": {
+			spanContext: ot.StartSpan("test.operation").Context(),
+			format:      opentracing.TextMap,
+			carrier:     "invalid-carrier",
+			want:        opentracing.ErrInvalidCarrier,
+		},
+		"ErrUnsupportedFormat": {
+			format: "unsupported-format",
+			want:   opentracing.ErrUnsupportedFormat,
+		},
+	} {
+		t.Run(name, func(t *testing.T) {
+			got := ot.Inject(tt.spanContext, tt.format, tt.carrier)
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}
+
+func TestExtractError(t *testing.T) {
+	ot := New()
+
+	for name, tt := range map[string]struct {
+		format  interface{}
+		carrier interface{}
+		want    error
+	}{
+		"ErrSpanContextNotFound": {
+			format:  opentracing.TextMap,
+			carrier: opentracing.TextMapCarrier(nil),
+			want:    opentracing.ErrSpanContextNotFound,
+		},
+		"ErrInvalidCarrier": {
+			format:  opentracing.TextMap,
+			carrier: "invalid-carrier",
+			want:    opentracing.ErrInvalidCarrier,
+		},
+		"ErrSpanContextCorrupted": {
+			format: opentracing.TextMap,
+			carrier: opentracing.TextMapCarrier(
+				map[string]string{
+					tracer.DefaultTraceIDHeader:  "-1",
+					tracer.DefaultParentIDHeader: "-1",
+					tracer.DefaultPriorityHeader: "not-a-number",
+				},
+			),
+			want: opentracing.ErrSpanContextCorrupted,
+		},
+		"ErrUnsupportedFormat": {
+			format: "unsupported-format",
+			want:   opentracing.ErrUnsupportedFormat,
+		},
+	} {
+		t.Run(name, func(t *testing.T) {
+			_, got := ot.Extract(tt.format, tt.carrier)
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}