vendor: add buildkit

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/grpc-ecosystem/grpc-opentracing/go/otgrpc/client.go

@@ -0,0 +1,239 @@
+package otgrpc
+
+import (
+	"github.com/opentracing/opentracing-go"
+	"github.com/opentracing/opentracing-go/ext"
+	"github.com/opentracing/opentracing-go/log"
+	"golang.org/x/net/context"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+	"io"
+	"runtime"
+	"sync/atomic"
+)
+
+// OpenTracingClientInterceptor returns a grpc.UnaryClientInterceptor suitable
+// for use in a grpc.Dial call.
+//
+// For example:
+//
+//     conn, err := grpc.Dial(
+//         address,
+//         ...,  // (existing DialOptions)
+//         grpc.WithUnaryInterceptor(otgrpc.OpenTracingClientInterceptor(tracer)))
+//
+// All gRPC client spans will inject the OpenTracing SpanContext into the gRPC
+// metadata; they will also look in the context.Context for an active
+// in-process parent Span and establish a ChildOf reference if such a parent
+// Span could be found.
+func OpenTracingClientInterceptor(tracer opentracing.Tracer, optFuncs ...Option) grpc.UnaryClientInterceptor {
+	otgrpcOpts := newOptions()
+	otgrpcOpts.apply(optFuncs...)
+	return func(
+		ctx context.Context,
+		method string,
+		req, resp interface{},
+		cc *grpc.ClientConn,
+		invoker grpc.UnaryInvoker,
+		opts ...grpc.CallOption,
+	) error {
+		var err error
+		var parentCtx opentracing.SpanContext
+		if parent := opentracing.SpanFromContext(ctx); parent != nil {
+			parentCtx = parent.Context()
+		}
+		if otgrpcOpts.inclusionFunc != nil &&
+			!otgrpcOpts.inclusionFunc(parentCtx, method, req, resp) {
+			return invoker(ctx, method, req, resp, cc, opts...)
+		}
+		clientSpan := tracer.StartSpan(
+			method,
+			opentracing.ChildOf(parentCtx),
+			ext.SpanKindRPCClient,
+			gRPCComponentTag,
+		)
+		defer clientSpan.Finish()
+		ctx = injectSpanContext(ctx, tracer, clientSpan)
+		if otgrpcOpts.logPayloads {
+			clientSpan.LogFields(log.Object("gRPC request", req))
+		}
+		err = invoker(ctx, method, req, resp, cc, opts...)
+		if err == nil {
+			if otgrpcOpts.logPayloads {
+				clientSpan.LogFields(log.Object("gRPC response", resp))
+			}
+		} else {
+			SetSpanTags(clientSpan, err, true)
+			clientSpan.LogFields(log.String("event", "error"), log.String("message", err.Error()))
+		}
+		if otgrpcOpts.decorator != nil {
+			otgrpcOpts.decorator(clientSpan, method, req, resp, err)
+		}
+		return err
+	}
+}
+
+// OpenTracingStreamClientInterceptor returns a grpc.StreamClientInterceptor suitable
+// for use in a grpc.Dial call. The interceptor instruments streaming RPCs by creating
+// a single span to correspond to the lifetime of the RPC's stream.
+//
+// For example:
+//
+//     conn, err := grpc.Dial(
+//         address,
+//         ...,  // (existing DialOptions)
+//         grpc.WithStreamInterceptor(otgrpc.OpenTracingStreamClientInterceptor(tracer)))
+//
+// All gRPC client spans will inject the OpenTracing SpanContext into the gRPC
+// metadata; they will also look in the context.Context for an active
+// in-process parent Span and establish a ChildOf reference if such a parent
+// Span could be found.
+func OpenTracingStreamClientInterceptor(tracer opentracing.Tracer, optFuncs ...Option) grpc.StreamClientInterceptor {
+	otgrpcOpts := newOptions()
+	otgrpcOpts.apply(optFuncs...)
+	return func(
+		ctx context.Context,
+		desc *grpc.StreamDesc,
+		cc *grpc.ClientConn,
+		method string,
+		streamer grpc.Streamer,
+		opts ...grpc.CallOption,
+	) (grpc.ClientStream, error) {
+		var err error
+		var parentCtx opentracing.SpanContext
+		if parent := opentracing.SpanFromContext(ctx); parent != nil {
+			parentCtx = parent.Context()
+		}
+		if otgrpcOpts.inclusionFunc != nil &&
+			!otgrpcOpts.inclusionFunc(parentCtx, method, nil, nil) {
+			return streamer(ctx, desc, cc, method, opts...)
+		}
+
+		clientSpan := tracer.StartSpan(
+			method,
+			opentracing.ChildOf(parentCtx),
+			ext.SpanKindRPCClient,
+			gRPCComponentTag,
+		)
+		ctx = injectSpanContext(ctx, tracer, clientSpan)
+		cs, err := streamer(ctx, desc, cc, method, opts...)
+		if err != nil {
+			clientSpan.LogFields(log.String("event", "error"), log.String("message", err.Error()))
+			SetSpanTags(clientSpan, err, true)
+			clientSpan.Finish()
+			return cs, err
+		}
+		return newOpenTracingClientStream(cs, method, desc, clientSpan, otgrpcOpts), nil
+	}
+}
+
+func newOpenTracingClientStream(cs grpc.ClientStream, method string, desc *grpc.StreamDesc, clientSpan opentracing.Span, otgrpcOpts *options) grpc.ClientStream {
+	finishChan := make(chan struct{})
+
+	isFinished := new(int32)
+	*isFinished = 0
+	finishFunc := func(err error) {
+		// The current OpenTracing specification forbids finishing a span more than
+		// once. Since we have multiple code paths that could concurrently call
+		// `finishFunc`, we need to add some sort of synchronization to guard against
+		// multiple finishing.
+		if !atomic.CompareAndSwapInt32(isFinished, 0, 1) {
+			return
+		}
+		close(finishChan)
+		defer clientSpan.Finish()
+		if err != nil {
+			clientSpan.LogFields(log.String("event", "error"), log.String("message", err.Error()))
+			SetSpanTags(clientSpan, err, true)
+		}
+		if otgrpcOpts.decorator != nil {
+			otgrpcOpts.decorator(clientSpan, method, nil, nil, err)
+		}
+	}
+	go func() {
+		select {
+		case <-finishChan:
+			// The client span is being finished by another code path; hence, no
+			// action is necessary.
+		case <-cs.Context().Done():
+			finishFunc(cs.Context().Err())
+		}
+	}()
+	otcs := &openTracingClientStream{
+		ClientStream: cs,
+		desc:         desc,
+		finishFunc:   finishFunc,
+	}
+
+	// The `ClientStream` interface allows one to omit calling `Recv` if it's
+	// known that the result will be `io.EOF`. See
+	// http://stackoverflow.com/q/42915337
+	// In such cases, there's nothing that triggers the span to finish. We,
+	// therefore, set a finalizer so that the span and the context goroutine will
+	// at least be cleaned up when the garbage collector is run.
+	runtime.SetFinalizer(otcs, func(otcs *openTracingClientStream) {
+		otcs.finishFunc(nil)
+	})
+	return otcs
+}
+
+type openTracingClientStream struct {
+	grpc.ClientStream
+	desc       *grpc.StreamDesc
+	finishFunc func(error)
+}
+
+func (cs *openTracingClientStream) Header() (metadata.MD, error) {
+	md, err := cs.ClientStream.Header()
+	if err != nil {
+		cs.finishFunc(err)
+	}
+	return md, err
+}
+
+func (cs *openTracingClientStream) SendMsg(m interface{}) error {
+	err := cs.ClientStream.SendMsg(m)
+	if err != nil {
+		cs.finishFunc(err)
+	}
+	return err
+}
+
+func (cs *openTracingClientStream) RecvMsg(m interface{}) error {
+	err := cs.ClientStream.RecvMsg(m)
+	if err == io.EOF {
+		cs.finishFunc(nil)
+		return err
+	} else if err != nil {
+		cs.finishFunc(err)
+		return err
+	}
+	if !cs.desc.ServerStreams {
+		cs.finishFunc(nil)
+	}
+	return err
+}
+
+func (cs *openTracingClientStream) CloseSend() error {
+	err := cs.ClientStream.CloseSend()
+	if err != nil {
+		cs.finishFunc(err)
+	}
+	return err
+}
+
+func injectSpanContext(ctx context.Context, tracer opentracing.Tracer, clientSpan opentracing.Span) context.Context {
+	md, ok := metadata.FromOutgoingContext(ctx)
+	if !ok {
+		md = metadata.New(nil)
+	} else {
+		md = md.Copy()
+	}
+	mdWriter := metadataReaderWriter{md}
+	err := tracer.Inject(clientSpan.Context(), opentracing.HTTPHeaders, mdWriter)
+	// We have no better place to record an error than the Span itself :-/
+	if err != nil {
+		clientSpan.LogFields(log.String("event", "Tracer.Inject() failed"), log.Error(err))
+	}
+	return metadata.NewOutgoingContext(ctx, md)
+}