Moved to google.golang.org/genproto/googleapis/api/annotations

Fixes #52

vendor/github.com/go-kit/kit/tracing/opentracing/endpoint.go

@@ -0,0 +1,55 @@
+package opentracing
+
+import (
+	"context"
+
+	"github.com/opentracing/opentracing-go"
+	otext "github.com/opentracing/opentracing-go/ext"
+
+	"github.com/go-kit/kit/endpoint"
+)
+
+// TraceServer returns a Middleware that wraps the `next` Endpoint in an
+// OpenTracing Span called `operationName`.
+//
+// If `ctx` already has a Span, it is re-used and the operation name is
+// overwritten. If `ctx` does not yet have a Span, one is created here.
+func TraceServer(tracer opentracing.Tracer, operationName string) endpoint.Middleware {
+	return func(next endpoint.Endpoint) endpoint.Endpoint {
+		return func(ctx context.Context, request interface{}) (interface{}, error) {
+			serverSpan := opentracing.SpanFromContext(ctx)
+			if serverSpan == nil {
+				// All we can do is create a new root span.
+				serverSpan = tracer.StartSpan(operationName)
+			} else {
+				serverSpan.SetOperationName(operationName)
+			}
+			defer serverSpan.Finish()
+			otext.SpanKindRPCServer.Set(serverSpan)
+			ctx = opentracing.ContextWithSpan(ctx, serverSpan)
+			return next(ctx, request)
+		}
+	}
+}
+
+// TraceClient returns a Middleware that wraps the `next` Endpoint in an
+// OpenTracing Span called `operationName`.
+func TraceClient(tracer opentracing.Tracer, operationName string) endpoint.Middleware {
+	return func(next endpoint.Endpoint) endpoint.Endpoint {
+		return func(ctx context.Context, request interface{}) (interface{}, error) {
+			var clientSpan opentracing.Span
+			if parentSpan := opentracing.SpanFromContext(ctx); parentSpan != nil {
+				clientSpan = tracer.StartSpan(
+					operationName,
+					opentracing.ChildOf(parentSpan.Context()),
+				)
+			} else {
+				clientSpan = tracer.StartSpan(operationName)
+			}
+			defer clientSpan.Finish()
+			otext.SpanKindRPCClient.Set(clientSpan)
+			ctx = opentracing.ContextWithSpan(ctx, clientSpan)
+			return next(ctx, request)
+		}
+	}
+}