// New returns an AddService backed by a gRPC client connection. It is the
// responsibility of the caller to dial, and later close, the connection.
func New(conn *grpc.ClientConn, tracer stdopentracing.Tracer, logger log.Logger) addsvc.Service {
// We construct a single ratelimiter middleware, to limit the total outgoing
// QPS from this client to all methods on the remote instance. We also
// construct per-endpoint circuitbreaker middlewares to demonstrate how
// that's done, although they could easily be combined into a single breaker
// for the entire remote instance, too.
limiter := ratelimit.NewTokenBucketLimiter(jujuratelimit.NewBucketWithRate(100, 100))
var sumEndpoint endpoint.Endpoint
{
sumEndpoint = grpctransport.NewClient(
conn,
"Add",
"Sum",
addsvc.EncodeGRPCSumRequest,
addsvc.DecodeGRPCSumResponse,
pb.SumReply{},
grpctransport.ClientBefore(opentracing.FromGRPCRequest(tracer, "Sum", logger)),
).Endpoint()
sumEndpoint = opentracing.TraceClient(tracer, "Sum")(sumEndpoint)
sumEndpoint = limiter(sumEndpoint)
sumEndpoint = circuitbreaker.Gobreaker(gobreaker.NewCircuitBreaker(gobreaker.Settings{
Name: "Sum",
Timeout: 30 * time.Second,
}))(sumEndpoint)
}
var concatEndpoint endpoint.Endpoint
{
concatEndpoint = grpctransport.NewClient(
conn,
"Add",
"Concat",
addsvc.EncodeGRPCConcatRequest,
addsvc.DecodeGRPCConcatResponse,
pb.ConcatReply{},
grpctransport.ClientBefore(opentracing.FromGRPCRequest(tracer, "Concat", logger)),
).Endpoint()
concatEndpoint = opentracing.TraceClient(tracer, "Concat")(concatEndpoint)
concatEndpoint = limiter(concatEndpoint)
concatEndpoint = circuitbreaker.Gobreaker(gobreaker.NewCircuitBreaker(gobreaker.Settings{
Name: "Concat",
Timeout: 30 * time.Second,
}))(concatEndpoint)
}
return addsvc.Endpoints{
SumEndpoint: sumEndpoint,
ConcatEndpoint: concatEndpoint,
}
}
func newGRPCBinding(ctx context.Context, tracer opentracing.Tracer, svc server.AddService, tracingLogger log.Logger) grpcBinding {
return grpcBinding{
sum: grpc.NewServer(
ctx,
kitot.TraceServer(tracer, "sum")(makeSumEndpoint(svc)),
servergrpc.DecodeSumRequest,
servergrpc.EncodeSumResponse,
grpc.ServerBefore(kitot.FromGRPCRequest(tracer, "", tracingLogger)),
),
concat: grpc.NewServer(
ctx,
kitot.TraceServer(tracer, "concat")(makeConcatEndpoint(svc)),
servergrpc.DecodeConcatRequest,
servergrpc.EncodeConcatResponse,
grpc.ServerBefore(kitot.FromGRPCRequest(tracer, "", tracingLogger)),
),
}
}
// MakeGRPCServer makes a set of endpoints available as a gRPC AddServer.
func MakeGRPCServer(ctx context.Context, endpoints Endpoints, tracer stdopentracing.Tracer, logger log.Logger) pb.AddServer {
options := []grpctransport.ServerOption{
grpctransport.ServerErrorLogger(logger),
}
return &grpcServer{
sum: grpctransport.NewServer(
ctx,
endpoints.SumEndpoint,
DecodeGRPCSumRequest,
EncodeGRPCSumResponse,
append(options, grpctransport.ServerBefore(opentracing.FromGRPCRequest(tracer, "Sum", logger)))...,
),
concat: grpctransport.NewServer(
ctx,
endpoints.ConcatEndpoint,
DecodeGRPCConcatRequest,
EncodeGRPCConcatResponse,
append(options, grpctransport.ServerBefore(opentracing.FromGRPCRequest(tracer, "Concat", logger)))...,
),
}
}
func TestTraceGRPCRequestRoundtrip(t *testing.T) {
logger := log.NewNopLogger()
tracer := mocktracer.New()
// Initialize the ctx with a Span to inject.
beforeSpan := tracer.StartSpan("to_inject").(*mocktracer.MockSpan)
defer beforeSpan.Finish()
beforeSpan.Context().SetBaggageItem("baggage", "check")
beforeCtx := opentracing.ContextWithSpan(context.Background(), beforeSpan)
toGRPCFunc := kitot.ToGRPCRequest(tracer, logger)
md := metadata.Pairs()
// Call the RequestFunc.
afterCtx := toGRPCFunc(beforeCtx, &md)
// The Span should not have changed.
afterSpan := opentracing.SpanFromContext(afterCtx)
if beforeSpan != afterSpan {
t.Errorf("Should not swap in a new span")
}
// No spans should have finished yet.
finishedSpans := tracer.GetFinishedSpans()
if want, have := 0, len(finishedSpans); want != have {
t.Errorf("Want %v span(s), found %v", want, have)
}
// Use FromGRPCRequest to verify that we can join with the trace given MD.
fromGRPCFunc := kitot.FromGRPCRequest(tracer, "joined", logger)
joinCtx := fromGRPCFunc(afterCtx, &md)
joinedSpan := opentracing.SpanFromContext(joinCtx).(*mocktracer.MockSpan)
joinedContext := joinedSpan.Context().(*mocktracer.MockSpanContext)
beforeContext := beforeSpan.Context().(*mocktracer.MockSpanContext)
if joinedContext.SpanID == beforeContext.SpanID {
t.Error("SpanID should have changed", joinedContext.SpanID, beforeContext.SpanID)
}
// Check that the parent/child relationship is as expected for the joined span.
if want, have := beforeContext.SpanID, joinedSpan.ParentID; want != have {
t.Errorf("Want ParentID %q, have %q", want, have)
}
if want, have := "joined", joinedSpan.OperationName; want != have {
t.Errorf("Want %q, have %q", want, have)
}
if want, have := "check", joinedSpan.Context().BaggageItem("baggage"); want != have {
t.Errorf("Want %q, have %q", want, have)
}
}