feat: helper function to initialize open telemetry SDK (#5)

go.mod

@@ -10,7 +10,11 @@ require (
 	github.com/gorilla/handlers v1.5.1
 	github.com/gorilla/mux v1.8.0
 	github.com/sirupsen/logrus v1.8.1
+	github.com/stretchr/objx v0.3.0 // indirect
 	github.com/stretchr/testify v1.7.0
 	go.opencensus.io v0.23.0
-	gopkg.in/yaml.v2 v2.4.0 // indirect
+	go.opentelemetry.io/otel v1.0.0-RC1
+	go.opentelemetry.io/otel/exporters/jaeger v1.0.0-RC1
+	go.opentelemetry.io/otel/sdk v1.0.0-RC1
+	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
 )

go.sum

@@ -277,6 +277,8 @@ github.com/spf13/jwalterweatherman v1.0.0/go.mod h1:cQK4TGJAtQXfYWX+Ddv3mKDzgVb6
 github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
 github.com/spf13/viper v1.3.2/go.mod h1:ZiWeW+zYFKm7srdB9IoDzzZXaJaI5eL9QjNiN/DMA2s=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.3.0 h1:NGXK3lHquSN08v5vWalVI/L8XU9hdzE/G6xsrze47As=
+github.com/stretchr/objx v0.3.0/go.mod h1:qt09Ya8vawLte6SNmTgCsAVtYtaKzEcn8ATUoHMkEqE=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
@@ -315,6 +317,16 @@ go.opencensus.io v0.22.5/go.mod h1:5pWMHQbX5EPX2/62yrJeAkowc+lfs/XD7Uxpq3pI6kk=
 go.opencensus.io v0.22.6/go.mod h1:XItmlyltB5F7CS4xOC1DcqMoFqwtC6OG2xF7mCv7P7E=
 go.opencensus.io v0.23.0 h1:gqCw0LfLxScz8irSi8exQc7fyQ0fKQU/qnC/X8+V/1M=
 go.opencensus.io v0.23.0/go.mod h1:XItmlyltB5F7CS4xOC1DcqMoFqwtC6OG2xF7mCv7P7E=
+go.opentelemetry.io/otel v1.0.0-RC1 h1:4CeoX93DNTWt8awGK9JmNXzF9j7TyOu9upscEdtcdXc=
+go.opentelemetry.io/otel v1.0.0-RC1/go.mod h1:x9tRa9HK4hSSq7jf2TKbqFbtt58/TGk0f9XiEYISI1I=
+go.opentelemetry.io/otel/exporters/jaeger v1.0.0-RC1 h1:tVhw2BMSAk248rhdeirOe9hlXKwGHDvVtF7P8F+H2DU=
+go.opentelemetry.io/otel/exporters/jaeger v1.0.0-RC1/go.mod h1:FXJnjGCoTQL6nQ8OpFJ0JI1DrdOvMoVx49ic0Hg4+D4=
+go.opentelemetry.io/otel/oteltest v1.0.0-RC1 h1:G685iP3XiskCwk/z0eIabL55XUl2gk0cljhGk9sB0Yk=
+go.opentelemetry.io/otel/oteltest v1.0.0-RC1/go.mod h1:+eoIG0gdEOaPNftuy1YScLr1Gb4mL/9lpDkZ0JjMRq4=
+go.opentelemetry.io/otel/sdk v1.0.0-RC1 h1:Sy2VLOOg24bipyC29PhuMXYNJrLsxkie8hyI7kUlG9Q=
+go.opentelemetry.io/otel/sdk v1.0.0-RC1/go.mod h1:kj6yPn7Pgt5ByRuwesbaWcRLA+V7BSDg3Hf8xRvsvf8=
+go.opentelemetry.io/otel/trace v1.0.0-RC1 h1:jrjqKJZEibFrDz+umEASeU3LvdVyWKlnTh7XEfwrT58=
+go.opentelemetry.io/otel/trace v1.0.0-RC1/go.mod h1:86UHmyHWFEtWjfWPSbu0+d0Pf9Q6e1U+3ViBOc+NXAg=
 golang.org/x/crypto v0.0.0-20181203042331-505ab145d0a9/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
@@ -678,12 +690,12 @@ gopkg.in/mgo.v2 v2.0.0-20180705113604-9856a29383ce/go.mod h1:yeKp02qBN3iKW1OzL3M
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWDmTeBkI65Dw0HsyUHuEVlX15mw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.8 h1:obN1ZagJSUGI0Ek/LBmuj4SNLPfIny3KsKFopxRdj10=
 gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
-gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
-gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.0-20191120175047-4206685974f2/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b h1:h8qDotaEPuJATrMmW04NCwg7v22aHH28wwpauUhK9Oo=
+gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/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 v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190418001031-e561f6794a2a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

metrics.go

@@ -10,6 +10,13 @@ import (
 	"go.opencensus.io/stats"
 	"go.opencensus.io/stats/view"
 	"go.opencensus.io/tag"
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/exporters/jaeger"
+	"go.opentelemetry.io/otel/propagation"
+	"go.opentelemetry.io/otel/sdk/resource"
+	tracesdk "go.opentelemetry.io/otel/sdk/trace"
+	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
 )
 
 // GenerateLatencyBounds is used in generating latency bounds
@@ -271,3 +278,57 @@ func (m *MetricsResponseWriter) Write(b []byte) (int, error) {
 	size, err := m.w.Write(b)
 	return size, err
 }
+
+// InitOtelSDK returns an OpenTelemetry TracerProvider configured to use
+// the Jaeger exporter for sending traces/spans. The returned
+// TracerProvider will also use a Resource configured with all the information
+// about the service deployment.
+func InitOtelSDK(ctx context.Context, serviceName string) (*tracesdk.TracerProvider, error) {
+	// Jaeger Exporter initialization
+	jaegerURL := MustGetEnvVar("JAEGER_URL")
+
+	exporter, err := jaeger.New(
+		jaeger.WithCollectorEndpoint(
+			jaeger.WithEndpoint(jaegerURL),
+		),
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	// Environment variables automatically added to the running containers in cloud run
+	// K_SERVICE	The name of the Cloud Run service being run.
+	service, _ := GetEnvVar("K_SERVICE")
+
+	// K_REVISION	The name of the Cloud Run revision being run.
+	revision, _ := GetEnvVar("K_REVISION")
+
+	// K_CONFIGURATION	The name of the Cloud Run configuration that created the revision.
+	configuration, _ := GetEnvVar("K_CONFIGURATION")
+
+	resource := resource.NewWithAttributes(
+		semconv.SchemaURL,
+		semconv.ServiceNameKey.String(MetricsCollectorService(serviceName)),
+		attribute.String("cloudrun.service", service),
+		attribute.String("cloudrun.revision", revision),
+		attribute.String("cloudrun.configuration", configuration),
+	)
+
+	tp := tracesdk.NewTracerProvider(
+		// Always be sure to batch in production.
+		tracesdk.WithBatcher(exporter),
+		tracesdk.WithResource(resource),
+	)
+
+	// Register the TracerProvider as the global so any imported
+	// instrumentation will default to using it
+	otel.SetTracerProvider(tp)
+
+	propagator := propagation.NewCompositeTextMapPropagator(
+		propagation.Baggage{},
+		propagation.TraceContext{},
+	)
+	otel.SetTextMapPropagator(propagator)
+
+	return tp, nil
+}

metrics_test.go

@@ -12,6 +12,7 @@ import (
 	"time"
 
 	"github.com/savannahghi/serverutils"
+	tracesdk "go.opentelemetry.io/otel/sdk/trace"
 )
 
 func TestRecordGraphqlResolverMetrics(t *testing.T) {
@@ -328,3 +329,80 @@ func TestGenerateLatencyBounds(t *testing.T) {
 		})
 	}
 }
+
+func TestInitOtelSDK(t *testing.T) {
+	type args struct {
+		ctx         context.Context
+		serviceName string
+	}
+	tests := []struct {
+		name      string
+		args      args
+		want      *tracesdk.TracerProvider
+		wantErr   bool
+		wantPanic bool
+	}{
+		{
+			name: "success:initialize otel sdk",
+			args: args{
+				ctx:         context.Background(),
+				serviceName: "test",
+			},
+			wantErr:   false,
+			wantPanic: false,
+		},
+		{
+			name: "fail:initialize otel sdk missing environment",
+			args: args{
+				ctx:         context.Background(),
+				serviceName: "test",
+			},
+			wantErr:   true,
+			wantPanic: true,
+		},
+		{
+			name: "fail:initialize otel sdk missing jaeger env",
+			args: args{
+				ctx:         context.Background(),
+				serviceName: "test",
+			},
+			wantErr:   true,
+			wantPanic: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			defer func() {
+				r := recover()
+				if (r != nil) != tt.wantPanic {
+					t.Errorf("InitOtelSDK() recover = %v, wantPanic = %v", r, tt.wantPanic)
+				}
+			}()
+
+			initialEnvironment := os.Getenv("ENVIRONMENT")
+			initialJaegerEnv := os.Getenv("JAEGER_URL")
+			if tt.name == "success:initialize otel sdk" {
+				os.Setenv("JAEGER_URL", "http://jaeger")
+				os.Setenv("ENVIRONMENT", "staging")
+			}
+
+			if tt.name == "fail:initialize otel sdk missing environment" {
+				os.Setenv("JAEGER_URL", "http://jaeger")
+				os.Setenv("ENVIRONMENT", "")
+			}
+
+			if tt.name == "fail:initialize otel sdk missing jaeger env" {
+				os.Setenv("JAEGER_URL", "")
+			}
+
+			_, err := serverutils.InitOtelSDK(tt.args.ctx, tt.args.serviceName)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("InitOtelSDK() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+
+			os.Setenv("ENVIRONMENT", initialEnvironment)
+			os.Setenv("JAEGER_URL", initialJaegerEnv)
+		})
+	}
+}