OpenTelemetry Collector Demo

.gitignore

@@ -17,3 +17,4 @@ coverage.*
 /example/namedtracer/namedtracer
 /example/prometheus/prometheus
 /example/zipkin/zipkin
+/example/otel-collector/otel-collector

example/otel-collector/README.md

@@ -0,0 +1,92 @@
+# OpenTelemetry Collector Traces Example
+
+This example illustrates how to export traces from the OpenTelemetry-Go SDK to the OpenTelemetry Collector, and from there to a Jaeger instance.
+The complete flow is:
+
+`otel-collector-demo -> otel-collector -> Jaeger`
+
+# Prerequisites
+
+The demo assumes you already have both an instance of the OpenTelemetry Collector and Jaeger up and running.
+For information about how to set these up, please follow the corresponding documentation:
+
+* Jaeger: https://www.jaegertracing.io/docs/1.17/getting-started/
+* OpenTelemetry Collector: https://opentelemetry.io/docs/collector/about/
+
+Moreover, this demo is built on a Kubernetes cluster running both the OpenTelemetry Collector, and Jaeger.
+Therefore, the included OpenTelemetry Collector configuration is a Kubernetes `ConfigMap`.
+However, the main concepts should be transferable to any other platform you want to run this demo on.
+
+# Configuring the OTEL Collector
+
+In order to enable our application to send traces to the OpenTelemetry Collector, we need to first configure the OTLP receiver:
+
+```yml
+receivers:
+      otlp: {}
+```
+
+This will create the receiver on the Collector side, and open up port `55680` for receiving traces.
+The rest of the configuration is quite standard, with the only mention that we need to create the Jaeger exporter:
+
+```yml
+exporters:
+      jaeger:
+        # Replace with a real endpoint.
+        endpoint: "<jaeger-service-url>:14250"
+```
+
+After this, apply the configuration to your OpenTelemetry Collector instance (with `kubectl apply -f otel-controller-config.yaml` for k8s users).
+You should see that the Collector creates the otlp receiver:
+
+```json
+{"level":"info","ts":1589184143.206609,"caller":"builder/receivers_builder.go:79","msg":"Receiver started.","component_kind":"receiver","component_type":"otlp","component_name":"otlp"}
+```
+and the Jaeger exporter:
+```json
+{"level":"info","ts":1589184143.1535392,"caller":"builder/exporters_builder.go:94","msg":"Exporter started.","component_kind":"exporter","component_type":"jaeger","component_name":"jaeger"}
+```
+
+# Writing the demo
+
+Having the OpenTelemetry Collector started with the OTLP port open for traces, and connected to Jaeger, let's look at the go app that will send traces to the Collector.
+
+First, we need to create an exporter using the otlp package:
+```go
+exp, _ := otlp.NewExporter(otlp.WithInsecure(),
+        // For debug purposes
+        otlp.WithGRPCDialOption(grpc.WithBlock()))
+defer func() {
+		_ = exp.Stop()
+	}()
+```
+This will initialize the exporter with the default configuration.
+In this configuration, it will try to connect to an OTLP receiver at the address `localhost:55680`.
+If your OpenTelemetry Collector is running at a different address, use the [`otlp.WithAddress`](https://pkg.go.dev/go.opentelemetry.io/otel/exporters/otlp?tab=doc#WithAddress) function to change the default address.
+
+Feel free to remove the blocking operation, but it might come in handy when testing the connection.
+Also, make sure to close the exporter before the app exits.
+
+The next steps are the same as for all other OpenTelemetry-Go SDK uses:
+1) Create a trace provider from the `otlp` exporter: 
+```go
+tp, _ := sdktrace.NewProvider(
+		sdktrace.WithConfig(sdktrace.Config{DefaultSampler: sdktrace.AlwaysSample()}),
+		sdktrace.WithBatcher(exp, // add following two options to ensure flush
+			sdktrace.WithScheduleDelayMillis(5),
+			sdktrace.WithMaxExportBatchSize(2),
+        ))
+```
+
+2) Start sending traces:
+```go
+tracer := tp.Tracer("test-tracer")
+ctx, span := tracer.Start(context.Background(), "CollectorExporter-Example")
+	defer span.End()
+```
+
+The traces should now be visible from the Jaeger UI (if you have it installed).
+
+# Notes
+
+* There is an issue with the exporter/Collector which causes Jaeger to throw errors when receiving spans from the OpenTelemetry Collector: https://github.com/open-telemetry/opentelemetry-collector/issues/815

example/otel-collector/go.mod

@@ -0,0 +1,10 @@
+module go.opentelemetry.io/otel/example/otel-collector
+
+go 1.14
+
+require (
+	github.com/open-telemetry/opentelemetry-collector v0.3.0
+	go.opentelemetry.io/otel v0.4.3
+	go.opentelemetry.io/otel/exporters/otlp v0.4.3
+	google.golang.org/grpc v1.29.1
+)