add go example

.github/workflows/acceptance-tests.yml

@@ -0,0 +1,29 @@
+name: Acceptance Tests
+
+on: [push]
+
+jobs:
+  acceptance-tests:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out
+        uses: actions/checkout@v4
+      - name: Check out oats
+        uses: actions/checkout@v4
+        with:
+          repository: grafana/oats
+          ref: f73c5c5eb1715296d0900eb5fc7c26fd14968b3f
+          path: oats
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: '1.21'
+          cache-dependency-path: oats/go.sum
+      - name: Run acceptance tests
+        run: ./scripts/run-acceptance-tests.sh
+      - name: upload log file
+        uses: actions/upload-artifact@v4
+        if: failure()
+        with:
+          name: docker-compose.log
+          path: oats/yaml/build/**/output.log

README.md

@@ -21,7 +21,7 @@ The Docker image is available on Docker hub: https://hub.docker.com/r/grafana/ot
 ## Run the Docker image
 
 ```sh
-docker run -p 3000:3000 -p 4317:4317 --rm -ti grafana/otel-lgtm
+docker run -p 3000:3000 -p 4317:4317 -p 4318:4318 --rm -ti grafana/otel-lgtm
 ```
 
 ## Send OpenTelemetry Data
@@ -59,3 +59,17 @@ Generate traffic:
 ./generate-traffic.sh
 ```
 
+## Run example apps in different languages
+
+The example apps are in the `examples/` directory.
+Each example has a `run.sh` script to start the app.
+
+Every example implements a rolldice service, which returns a random number between 1 and 6.
+
+Each example uses a different application port (to be able to run all applications at the same time).
+
+| Example | Service URL                           |
+|---------|---------------------------------------|
+| Java    | `curl http://localhost:8080/rolldice` |
+| Go      | `curl http://localhost:8081/rolldice` |
+

docker/run-all.sh

@@ -17,7 +17,8 @@ done
 echo "The OpenTelemtry collector and the Grafana LGTM stack are up and running!"
 
 echo "Open ports:"
-echo " - 4317: OpenTelemetry endpoint"
+echo " - 4317: OpenTelemetry GRPC endpoint"
+echo " - 4318: OpenTelemetry HTTP endpoint"
 echo " - 3000: Grafana. User: admin, password: admin"
 
 sleep infinity

examples/go/Dockerfile

@@ -0,0 +1,27 @@
+# syntax=docker/dockerfile:1
+
+FROM golang:1.21
+
+# Set destination for COPY
+WORKDIR /app
+
+# Download Go modules
+COPY go.mod go.sum ./
+RUN go mod download
+
+# Copy the source code. Note the slash at the end, as explained in
+# https://docs.docker.com/engine/reference/builder/#copy
+COPY *.go ./
+
+# Build
+RUN CGO_ENABLED=0 GOOS=linux go build -o /rolldice
+
+# Optional:
+# To bind to a TCP port, runtime parameters must be supplied to the docker command.
+# But we can document in the Dockerfile what ports
+# the application is going to listen on by default.
+# https://docs.docker.com/engine/reference/builder/#expose
+EXPOSE 8081
+
+# Run
+CMD ["/rolldice"]

examples/go/docker-compose.oats.yml

@@ -0,0 +1,13 @@
+# OATS is an acceptance testing framework for OpenTelemetry - https://github.com/grafana/oats/tree/main/yaml
+version: '3.4'
+
+services:
+  go:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    environment:
+      OTEL_EXPORTER_OTLP_ENDPOINT: http://collector:4318
+      OTEL_METRIC_EXPORT_INTERVAL: "5000"  # so we don't have to wait 60s for metrics
+    ports:
+      - "8080:8081"

examples/go/go.mod

@@ -0,0 +1,33 @@
+module dice
+
+go 1.21.1
+
+require (
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.47.0
+	go.opentelemetry.io/contrib/instrumentation/runtime v0.47.0
+	go.opentelemetry.io/otel v1.23.0-rc.1
+	go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp v0.45.0
+	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.22.0
+	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.22.0
+	go.opentelemetry.io/otel/sdk v1.23.0-rc.1
+	go.opentelemetry.io/otel/sdk/metric v1.23.0-rc.1
+)
+
+require (
+	github.com/cenkalti/backoff/v4 v4.2.1 // indirect
+	github.com/felixge/httpsnoop v1.0.4 // indirect
+	github.com/go-logr/logr v1.4.1 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/golang/protobuf v1.5.3 // indirect
+	github.com/grpc-ecosystem/grpc-gateway/v2 v2.19.0 // indirect
+	go.opentelemetry.io/otel/metric v1.23.0-rc.1 // indirect
+	go.opentelemetry.io/otel/trace v1.23.0-rc.1 // indirect
+	go.opentelemetry.io/proto/otlp v1.1.0 // indirect
+	golang.org/x/net v0.20.0 // indirect
+	golang.org/x/sys v0.16.0 // indirect
+	golang.org/x/text v0.14.0 // indirect
+	google.golang.org/genproto/googleapis/api v0.0.0-20240125205218-1f4bbc51befe // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20240125205218-1f4bbc51befe // indirect
+	google.golang.org/grpc v1.61.0 // indirect
+	google.golang.org/protobuf v1.32.0 // indirect
+)

examples/go/go.sum

@@ -0,0 +1,66 @@
+github.com/cenkalti/backoff/v4 v4.2.1 h1:y4OZtCnogmCPw98Zjyt5a6+QwPLGkiQsYW5oUqylYbM=
+github.com/cenkalti/backoff/v4 v4.2.1/go.mod h1:Y3VNntkOUPxTVeUxJ/G5vcM//AlwfmyYozVcomhLiZE=
+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/felixge/httpsnoop v1.0.4 h1:NFTV2Zj1bL4mc9sqWACXbQFVBBg2W3GPvqp8/ESS2Wg=
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+github.com/go-logr/logr v1.4.1 h1:pKouT5E8xu9zeFC39JXRDukb6JFQPXM5p5I91188VAQ=
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+github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
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+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.47.0 h1:sv9kVfal0MK0wBMCOGr+HeJm9v803BkJxGrk2au7j08=
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+go.opentelemetry.io/contrib/instrumentation/runtime v0.47.0/go.mod h1:oEBtteRW7mKJc+yAKRuEu0xk5wyPUKpm41/bDM4ZKeY=
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+go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.22.0 h1:FyjCyI9jVEfqhUh2MoSkmolPjfh5fp2hnV0b0irxH4Q=
+go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.22.0/go.mod h1:hYwym2nDEeZfG/motx0p7L7J1N1vyzIThemQsb4g2qY=
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examples/go/main.go

@@ -0,0 +1,83 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"log"
+	"net"
+	"net/http"
+	"os"
+	"os/signal"
+	"time"
+
+	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
+)
+
+func main() {
+	if err := run(); err != nil {
+		log.Fatalln(err)
+	}
+}
+
+func run() (err error) {
+	// Handle SIGINT (CTRL+C) gracefully.
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
+	defer stop()
+
+	// Set up OpenTelemetry.
+	otelShutdown, err := setupOTelSDK(ctx)
+	if err != nil {
+		return
+	}
+	// Handle shutdown properly so nothing leaks.
+	defer func() {
+		err = errors.Join(err, otelShutdown(context.Background()))
+	}()
+
+	// Start HTTP server.
+	srv := &http.Server{
+		Addr:         ":8081",
+		BaseContext:  func(_ net.Listener) context.Context { return ctx },
+		ReadTimeout:  time.Second,
+		WriteTimeout: 10 * time.Second,
+		Handler:      newHTTPHandler(),
+	}
+	srvErr := make(chan error, 1)
+	go func() {
+		srvErr <- srv.ListenAndServe()
+	}()
+
+	// Wait for interruption.
+	select {
+	case err = <-srvErr:
+		// Error when starting HTTP server.
+		return
+	case <-ctx.Done():
+		// Wait for first CTRL+C.
+		// Stop receiving signal notifications as soon as possible.
+		stop()
+	}
+
+	// When Shutdown is called, ListenAndServe immediately returns ErrServerClosed.
+	err = srv.Shutdown(context.Background())
+	return
+}
+
+func newHTTPHandler() http.Handler {
+	mux := http.NewServeMux()
+
+	// handleFunc is a replacement for mux.HandleFunc
+	// which enriches the handler's HTTP instrumentation with the pattern as the http.route.
+	handleFunc := func(pattern string, handlerFunc func(http.ResponseWriter, *http.Request)) {
+		// Configure the "http.route" for the HTTP instrumentation.
+		handler := otelhttp.WithRouteTag(pattern, http.HandlerFunc(handlerFunc))
+		mux.Handle(pattern, handler)
+	}
+
+	// Register handlers.
+	handleFunc("/rolldice", rolldice)
+
+	// Add HTTP instrumentation for the whole server.
+	handler := otelhttp.NewHandler(mux, "/")
+	return handler
+}

examples/go/oats.yaml

@@ -0,0 +1,17 @@
+# OATS is an acceptance testing framework for OpenTelemetry - https://github.com/grafana/oats/tree/main/yaml
+docker-compose:
+  generator: lgtm
+  files:
+    - ./docker-compose.oats.yml
+input:
+  - path: /rolldice
+expected:
+  traces:
+    - traceql: '{ span.http.route = "/rolldice" }'
+      spans:
+        - name: '/' # should be "GET /rolldice"
+          attributes:
+            otel.library.name: go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp
+  metrics:
+    - promql: 'process_runtime_go_goroutines{}'
+      value: "> 0"