Add GetLightStepReporterID helper (#141)

* Add GetLightStepReporterID helper

* Test three cases

tracer_0_14._test.go

@@ -9,6 +9,7 @@ import (
 	"github.com/lightstep/lightstep-tracer-go/lightstepfakes"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
+	opentracing "github.com/opentracing/opentracing-go"
 )
 
 var _ = Describe("Tracerv0_14", func() {
@@ -71,4 +72,12 @@ var _ = Describe("Tracerv0_14", func() {
 			Expect(err).ToNot(HaveOccurred())
 		})
 	})
+
+	Describe("provides its ReporterID", func() {
+		It("is non-zero", func() {
+			rid, err := lightstep.GetLightStepReporterID(opentracing.Tracer(tracer))
+			Expect(err).To(BeNil())
+			Expect(rid).To(Not(BeZero()))
+		})
+	})
 })

tracer_helpers.go

@@ -67,3 +67,15 @@ func CloseTracer(tracer opentracing.Tracer) error {
 		return newEventUnsupportedTracer(tracer)
 	}
 }
+
+// GetLightStepReporterID returns the currently configured Reporter ID.
+func GetLightStepReporterID(tracer opentracing.Tracer) (uint64, error) {
+	switch lsTracer := tracer.(type) {
+	case *tracerImpl:
+		return lsTracer.reporterID, nil
+	case *tracerv0_14:
+		return GetLightStepReporterID(lsTracer.Tracer)
+	default:
+		return 0, newEventUnsupportedTracer(tracer)
+	}
+}

tracer_test.go

@@ -16,6 +16,7 @@ import (
 	"github.com/lightstep/lightstep-tracer-go/lightstepfakes"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
+	opentracing "github.com/opentracing/opentracing-go"
 )
 
 var _ = Describe("Tracer", func() {
@@ -284,4 +285,36 @@ var _ = Describe("Tracer", func() {
 			Expect(span.Finish).ToNot(Panic())
 		})
 	})
+
+	Describe("provides its ReporterID", func() {
+		BeforeEach(func() {
+			opts = Options{
+				AccessToken: accessToken,
+				ConnFactory: fakeConn,
+				Recorder:    nil,
+			}
+		})
+
+		It("is non-zero", func() {
+			rid, err := GetLightStepReporterID(tracer)
+			Expect(err).To(BeNil())
+			Expect(rid).To(Not(BeZero()))
+		})
+	})
+})
+
+var _ = Describe("UnsupportedTracer", func() {
+	type unsupportedTracer struct {
+		opentracing.Tracer
+	}
+
+	tracer := unsupportedTracer{}
+
+	Describe("has no ReporterID", func() {
+		It("is an error", func() {
+			rid, err := GetLightStepReporterID(tracer)
+			Expect(err).To(Not(BeNil()))
+			Expect(rid).To(BeZero())
+		})
+	})
 })