feat(transport): add OpenTelemetry context propagation

go.mod

@@ -10,6 +10,8 @@ require (
 	github.com/googleapis/enterprise-certificate-proxy v0.3.2
 	github.com/googleapis/gax-go/v2 v2.12.0
 	go.opencensus.io v0.24.0
+	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.46.1
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.46.0
 	golang.org/x/net v0.18.0
 	golang.org/x/oauth2 v0.14.0
 	golang.org/x/sync v0.5.0
@@ -22,8 +24,14 @@ require (
 
 require (
 	cloud.google.com/go/compute v1.23.3 // indirect
+	github.com/felixge/httpsnoop v1.0.4 // indirect
+	github.com/go-logr/logr v1.3.0 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
+	go.opentelemetry.io/otel v1.21.0 // indirect
+	go.opentelemetry.io/otel/metric v1.21.0 // indirect
+	go.opentelemetry.io/otel/trace v1.21.0 // indirect
 	golang.org/x/crypto v0.15.0 // indirect
 	golang.org/x/sys v0.14.0 // indirect
 	golang.org/x/text v0.14.0 // indirect

go.sum

@@ -7,12 +7,22 @@ github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
 github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGXZJjfX53e64911xZQV5JYwmTeXPW+k8Sc=
+github.com/cncf/xds/go v0.0.0-20230607035331-e9ce68804cb4 h1:/inchEIKaYC1Akx+H+gqO04wryn5h75LSazbRlnya1k=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
+github.com/envoyproxy/protoc-gen-validate v1.0.2 h1:QkIBuU5k+x7/QXPvPPnWXWlCdaBFApVqftFV6k087DA=
+github.com/felixge/httpsnoop v1.0.4 h1:NFTV2Zj1bL4mc9sqWACXbQFVBBg2W3GPvqp8/ESS2Wg=
+github.com/felixge/httpsnoop v1.0.4/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
+github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
+github.com/go-logr/logr v1.3.0 h1:2y3SDp0ZXuc6/cjLSZ+Q3ir+QB9T/iG5yYRXqsagWSY=
+github.com/go-logr/logr v1.3.0/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
+github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
+github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
 github.com/golang/groupcache v0.0.0-20200121045136-8c9f03a8e57e/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
 github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da h1:oI5xCqsCo564l8iNU+DwB5epxmsaqB+rhGL0m5jtYqE=
@@ -49,6 +59,7 @@ github.com/googleapis/enterprise-certificate-proxy v0.3.2 h1:Vie5ybvEvT75RniqhfF
 github.com/googleapis/enterprise-certificate-proxy v0.3.2/go.mod h1:VLSiSSBs/ksPL8kq3OBOQ6WRI2QnaFynd1DCjZ62+V0=
 github.com/googleapis/gax-go/v2 v2.12.0 h1:A+gCJKdRfqXkr+BIRGtZLibNXf0m1f9E4HG56etFpas=
 github.com/googleapis/gax-go/v2 v2.12.0/go.mod h1:y+aIqrI5eb1YGMVJfuV3185Ts/D7qKpsEkdD5+I6QGU=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
@@ -57,8 +68,19 @@ github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpE
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 go.opencensus.io v0.24.0 h1:y73uSU6J157QMP2kn2r30vwW1A2W2WFwSCGnAVxeaD0=
 go.opencensus.io v0.24.0/go.mod h1:vNK8G9p7aAivkbmorf4v+7Hgx+Zs0yY+0fOtgBfjQKo=
+go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.46.1 h1:SpGay3w+nEwMpfVnbqOLH5gY52/foP8RE8UzTZ1pdSE=
+go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.46.1/go.mod h1:4UoMYEZOC0yN/sPGH76KPkkU7zgiEWYWL9vwmbnTJPE=
+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.46.0 h1:1eHu3/pUSWaOgltNK3WJFaywKsTIr/PwvHyDmi0lQA0=
+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.46.0/go.mod h1:HyABWq60Uy1kjJSa2BVOxUVao8Cdick5AWSKPutqy6U=
+go.opentelemetry.io/otel v1.21.0 h1:hzLeKBZEL7Okw2mGzZ0cc4k/A7Fta0uoPgaJCr8fsFc=
+go.opentelemetry.io/otel v1.21.0/go.mod h1:QZzNPQPm1zLX4gZK4cMi+71eaorMSGT3A4znnUvNNEo=
+go.opentelemetry.io/otel/metric v1.21.0 h1:tlYWfeo+Bocx5kLEloTjbcDwBuELRrIFxwdQ36PlJu4=
+go.opentelemetry.io/otel/metric v1.21.0/go.mod h1:o1p3CA8nNHW8j5yuQLdc1eeqEaPfzug24uvsyIEJRWM=
+go.opentelemetry.io/otel/trace v1.21.0 h1:WD9i5gzvoUPuXIXH24ZNBudiarZDKuekPqi/E8fpfLc=
+go.opentelemetry.io/otel/trace v1.21.0/go.mod h1:LGbsEB0f9LGjN+OZaQQ26sohbOmiMR+BaslueVtS/qQ=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.15.0 h1:frVn1TEaCEaZcn3Tmd7Y2b5KKPaZ+I32Q2OA3kYp5TA=
@@ -140,6 +162,7 @@ google.golang.org/protobuf v1.31.0 h1:g0LDEJHgrBl9N9r17Ru3sqWhkIx2NB67okBHPwC7hs
 google.golang.org/protobuf v1.31.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190523083050-ea95bdfd59fc/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

go.work.sum

@@ -14,5 +14,6 @@ golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.6.0/go.mod h1:m6U89DPEgQRMq3DNkDClhWw02AUbt2daBVO4cn4Hv9U=
 golang.org/x/term v0.8.0/go.mod h1:xPskH00ivmX89bAKVGSKKtLOWNx2+17Eiy94tnKShWo=
 golang.org/x/term v0.10.0/go.mod h1:lpqdcUyK/oCiQxvxVrppt5ggO2KCZ5QblwqPnfZ6d5o=
+golang.org/x/term v0.14.0/go.mod h1:TySc+nGkYR6qt8km8wUhuFRTVSMIX3XPR58y2lC8vww=
 golang.org/x/text v0.8.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
 golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=

transport/grpc/dial.go

@@ -18,6 +18,7 @@ import (
 
 	"cloud.google.com/go/compute/metadata"
 	"go.opencensus.io/plugin/ocgrpc"
+	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
 	"golang.org/x/oauth2"
 	"golang.org/x/time/rate"
 	"google.golang.org/api/internal"
@@ -43,6 +44,9 @@ var timeoutDialerOption grpc.DialOption
 // Log rate limiter
 var logRateLimiter = rate.Sometimes{Interval: 1 * time.Second}
 
+// Assign to var for unit test replacement
+var dialContext = grpc.DialContext
+
 // Dial returns a GRPC connection for use communicating with a Google cloud
 // service, configured with the given ClientOptions.
 func Dial(ctx context.Context, opts ...option.ClientOption) (*grpc.ClientConn, error) {
@@ -195,12 +199,13 @@ func dial(ctx context.Context, insecure bool, o *internal.DialSettings) (*grpc.C
 	// gRPC stats handler.
 	// This assumes that gRPC options are processed in order, left to right.
 	grpcOpts = addOCStatsHandler(grpcOpts, o)
+	grpcOpts = addOpenTelemetryStatsHandler(grpcOpts, o)
 	grpcOpts = append(grpcOpts, o.GRPCDialOpts...)
 	if o.UserAgent != "" {
 		grpcOpts = append(grpcOpts, grpc.WithUserAgent(o.UserAgent))
 	}
 
-	return grpc.DialContext(ctx, endpoint, grpcOpts...)
+	return dialContext(ctx, endpoint, grpcOpts...)
 }
 
 func addOCStatsHandler(opts []grpc.DialOption, settings *internal.DialSettings) []grpc.DialOption {
@@ -210,6 +215,13 @@ func addOCStatsHandler(opts []grpc.DialOption, settings *internal.DialSettings)
 	return append(opts, grpc.WithStatsHandler(&ocgrpc.ClientHandler{}))
 }
 
+func addOpenTelemetryStatsHandler(opts []grpc.DialOption, settings *internal.DialSettings) []grpc.DialOption {
+	if settings.TelemetryDisabled {
+		return opts
+	}
+	return append(opts, grpc.WithStatsHandler(otelgrpc.NewClientHandler()))
+}
+
 // grpcTokenSource supplies PerRPCCredentials from an oauth.TokenSource.
 type grpcTokenSource struct {
 	oauth.TokenSource

transport/grpc/dial_test.go

@@ -14,8 +14,21 @@ import (
 	"cloud.google.com/go/compute/metadata"
 	"golang.org/x/oauth2/google"
 	"google.golang.org/api/internal"
+	"google.golang.org/grpc"
 )
 
+func TestDial(t *testing.T) {
+	dialContext = func(ctxGot context.Context, target string, opts ...grpc.DialOption) (conn *grpc.ClientConn, err error) {
+		if len(opts) != 4 {
+			t.Fatalf("got: %d, want: 4", len(opts))
+		}
+		return nil, nil
+	}
+
+	var o internal.DialSettings
+	dial(context.Background(), false, &o)
+}
+
 func TestCheckDirectPathEndPoint(t *testing.T) {
 	for _, testcase := range []struct {
 		name     string

transport/http/dial.go

@@ -16,6 +16,7 @@ import (
 	"time"
 
 	"go.opencensus.io/plugin/ochttp"
+	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 	"golang.org/x/net/http2"
 	"golang.org/x/oauth2"
 	"google.golang.org/api/googleapi/transport"
@@ -69,6 +70,9 @@ func newTransport(ctx context.Context, base http.RoundTripper, settings *interna
 		requestReason: settings.RequestReason,
 	}
 	var trans http.RoundTripper = paramTransport
+	// Give OpenTelemetry precedence over OpenCensus in case user configuration
+	// causes both to write the same header (`X-Cloud-Trace-Context`).
+	trans = addOpenTelemetryTransport(trans, settings)
 	trans = addOCTransport(trans, settings)
 	switch {
 	case settings.NoAuth:
@@ -203,6 +207,13 @@ func fallbackBaseTransport() *http.Transport {
 	}
 }
 
+func addOpenTelemetryTransport(trans http.RoundTripper, settings *internal.DialSettings) http.RoundTripper {
+	if settings.TelemetryDisabled {
+		return trans
+	}
+	return otelhttp.NewTransport(trans)
+}
+
 func addOCTransport(trans http.RoundTripper, settings *internal.DialSettings) http.RoundTripper {
 	if settings.TelemetryDisabled {
 		return trans

transport/http/dial_test.go

@@ -0,0 +1,39 @@
+// Copyright 2023 Google LLC.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package http
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"go.opencensus.io/plugin/ochttp"
+	"golang.org/x/oauth2"
+)
+
+func TestNewClient(t *testing.T) {
+	client, endpoint, err := NewClient(context.Background())
+
+	if err != nil {
+		t.Fatalf("unable to create client: %v", err)
+	}
+	if client == nil {
+		t.Fatalf("client is nil")
+	}
+	if endpoint != "" {
+		t.Errorf("got: %s, want: ''", endpoint)
+	}
+	if got, want := fmt.Sprintf("%T", client.Transport), "*oauth2.Transport"; got != want {
+		t.Fatalf("got %s, want: %s", got, want)
+	}
+	t1 := client.Transport.(*oauth2.Transport)
+	if got, want := fmt.Sprintf("%T", t1.Base), "*ochttp.Transport"; got != want {
+		t.Fatalf("got %s, want: %s", got, want)
+	}
+	t2 := t1.Base.(*ochttp.Transport)
+	if got, want := fmt.Sprintf("%T", t2.Base), "*otelhttp.Transport"; got != want {
+		t.Fatalf("got %s, want: %s", got, want)
+	}
+}