Unify trace and metric exporter helpers (#944)

* Adjust Jaeger and Zipkin exporters helper methods

* Update and add tests, examples, various minor improvements

* Update changelog

* Correct the Zipkin example

- wait for the spans to be exported
- rebuild the example

* Zipkin service name as argument

* Rework Jaeger and Zipkin tests

* Include more detailed Changelog

Co-authored-by: ET <evantorrie@users.noreply.github.com>
Co-authored-by: Liz Fong-Jones <lizf@honeycomb.io>
Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>

example/jaeger/main.go

@@ -30,7 +30,7 @@ import (
 // initTracer creates a new trace provider instance and registers it as global trace provider.
 func initTracer() func() {
 	// Create and install Jaeger export pipeline
-	_, flush, err := jaeger.NewExportPipeline(
+	flush, err := jaeger.InstallNewPipeline(
 		jaeger.WithCollectorEndpoint("http://localhost:14268/api/traces"),
 		jaeger.WithProcess(jaeger.Process{
 			ServiceName: "trace-demo",
@@ -39,7 +39,6 @@ func initTracer() func() {
 				kv.Float64("float", 312.23),
 			},
 		}),
-		jaeger.RegisterAsGlobal(),
 		jaeger.WithSDK(&sdktrace.Config{DefaultSampler: sdktrace.AlwaysSample()}),
 	)
 	if err != nil {

example/zipkin/main.go

@@ -33,30 +33,20 @@ var logger = log.New(os.Stderr, "zipkin-example", log.Ldate|log.Ltime|log.Llongf
 
 // initTracer creates a new trace provider instance and registers it as global trace provider.
 func initTracer(url string) {
-	// Create Zipkin Exporter
-	exporter, err := zipkin.NewExporter(
-		url,
-		"zipkin-example",
-		zipkin.WithLogger(logger),
-	)
-	if err != nil {
-		log.Fatal(err)
-	}
-
+	// Create Zipkin Exporter and install it as a global tracer.
+	//
 	// For demoing purposes, always sample. In a production application, you should
-	// configure this to a trace.ProbabilitySampler set at the desired
+	// configure the sampler to a trace.ProbabilitySampler set at the desired
 	// probability.
-	tp, err := sdktrace.NewProvider(
-		sdktrace.WithConfig(sdktrace.Config{DefaultSampler: sdktrace.AlwaysSample()}),
-		sdktrace.WithBatcher(exporter,
-			sdktrace.WithBatchTimeout(5),
-			sdktrace.WithMaxExportBatchSize(10),
-		),
+	err := zipkin.InstallNewPipeline(
+		url,
+		"zipkin-test",
+		zipkin.WithLogger(logger),
+		zipkin.WithSDK(&sdktrace.Config{DefaultSampler: sdktrace.AlwaysSample()}),
 	)
 	if err != nil {
 		log.Fatal(err)
 	}
-	global.SetTraceProvider(tp)
 }
 
 func main() {
@@ -73,7 +63,9 @@ func main() {
 	bar(ctx)
 	<-time.After(6 * time.Millisecond)
 	span.End()
-	<-time.After(24 * time.Millisecond)
+
+	// Wait for the spans to be exported.
+	<-time.After(5 * time.Second)
 }
 
 func bar(ctx context.Context) {