Add Go sample app (#35)

README.md

@@ -102,7 +102,7 @@ the operator in various languages:
 * [Java](sample-apps/java)
 * [Python](sample-apps/python)
 * DotNET (coming soon)
-* Go (coming soon)
+* [Go](sample-apps/go)
 * [NodeJS + Java](sample-apps/nodejs-java)
 
 Each of these sample apps works well with the [recipes](recipes) listed below.

sample-apps/README.md

@@ -7,7 +7,7 @@ the operator and auto-instrumentation. See below to get started:
 * [Java](java)
 * [Python](python)
 * DotNET
-* Go
+* [Go](go)
 * [NodeJS + Java](nodejs-java)
 
 ## Setup

sample-apps/go/Makefile

@@ -0,0 +1,26 @@
+# Copyright 2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+include ../../Makefile
+
+.PHONY: build
+build: sample-replace
+	docker build -t ${REGISTRY_LOCATION}-docker.pkg.dev/${GCLOUD_PROJECT}/${CONTAINER_REGISTRY}/go-sample-app app
+	docker build -t ${REGISTRY_LOCATION}-docker.pkg.dev/${GCLOUD_PROJECT}/${CONTAINER_REGISTRY}/go-sample-server server
+
+.PHONY: push
+push:
+	docker push ${REGISTRY_LOCATION}-docker.pkg.dev/${GCLOUD_PROJECT}/${CONTAINER_REGISTRY}/go-sample-app:latest
+	docker push ${REGISTRY_LOCATION}-docker.pkg.dev/${GCLOUD_PROJECT}/${CONTAINER_REGISTRY}/go-sample-server:latest
+

sample-apps/go/README.md

@@ -0,0 +1,54 @@
+# Go sample app
+
+This is a sample app consisting of a basic client and server written in Go. The
+server listens for requests which the client makes on a timed loop.
+
+## Prerequisites
+
+* OpenTelemetry Operator installed in your cluster
+* Artifact Registry set up in your GCP project (see the 
+[main README.md](../../README.md#sample-applications))
+* An `OpenTelemetryCollector` object already created in the current namespace,
+  such as [the sample `collector-config.yaml`](../../README.md#starting-the-Collector)
+  from the main [README](../../README.md)
+* An `Instrumentation` object already created in the current namespace,
+  such as [the sample `instrumentation.yaml`](../../README.md#auto-instrumenting-applications)
+  from the main [README](../../README.md)
+
+## Running
+
+1. Build the sample app:
+   ```
+   make build
+   ```
+   This command will also update the local [manifests](k8s)
+   to refer to your image location.
+
+2. Push the local image to the Artifact Registry you created
+   in the setup steps (if you did not create one, or are using an already created registry,
+   make sure to set the `REGISTRY_LOCATION` and `CONTAINER_REGISTRY` variables):
+   ```
+   make push
+   ```
+
+3. Deploy the app in your cluster:
+   ```
+   kubectl apply -f k8s/.
+   ```
+   If you want to run the sample app in a specific namespace, pass `-n <your-namespace>`.
+
+4. Run the following commands to patch the `app` and `server` deployments for auto-instrumentation:
+   ```
+   kubectl patch deployment.apps/goshowcase-app -p '{"spec":{"template":{"metadata":{"annotations":{"instrumentation.opentelemetry.io/inject-go": "true", "instrumentation.opentelemetry.io/otel-go-auto-target-exe": "/app/main"}}}}}'
+   kubectl patch deployment.apps/goshowcase-server -p '{"spec":{"template":{"metadata":{"annotations":{"instrumentation.opentelemetry.io/inject-go": "true", "instrumentation.opentelemetry.io/otel-go-auto-target-exe": "/server/main"}}}}}'
+   ```
+   These commands will use the `Instrumentation` created as part of the Prerequisites.
+
+## View your Spans
+
+To stream logs from the otel-collector, which will include spans from this sample application, run:
+```
+kubectl logs deployment/otel-collector -f
+```
+
+Alternatively, follow the [cloud-trace recipe](../../recipes/cloud-trace/) to view your spans in Google Cloud Trace.

sample-apps/go/app/Dockerfile

@@ -0,0 +1,18 @@
+# Copyright 2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+FROM golang:1.19
+WORKDIR /app
+COPY . .
+RUN go build -o main

sample-apps/go/app/go.mod

@@ -0,0 +1,3 @@
+module github.com/GoogleCloudPlatform/opentelemetry-operator-sample/sample-apps/go/app
+
+go 1.20

sample-apps/go/app/main.go

@@ -0,0 +1,42 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"io"
+	"log"
+	"net/http"
+	"time"
+)
+
+func main() {
+	for {
+		resp, err := http.Get("http://goshowcase-server/hello")
+		if err != nil {
+			log.Fatal(err)
+		}
+		body, err := io.ReadAll(resp.Body)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		log.Printf("Body: %s\n", string(body))
+		err = resp.Body.Close()
+		if err != nil {
+			log.Fatal(err)
+		}
+		time.Sleep(5 * time.Second)
+	}
+}

sample-apps/go/k8s/app.yaml

@@ -0,0 +1,40 @@
+# Copyright 2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: goshowcase-app
+spec:
+  selector:
+    matchLabels:
+      app: goshowcase-app
+  template:
+    metadata:
+      name: goshowcase-app
+      labels:
+        app: goshowcase-app
+    spec:
+      containers:
+        - name: goshowcase-app
+          image: "%REGISTRY_LOCATION%-docker.pkg.dev/%GCLOUD_PROJECT%/%CONTAINER_REGISTRY%/go-sample-app:latest"
+          command: ['/app/main']
+          resources:
+            requests:
+              memory: "256Mi"
+              cpu: "250m"
+            limits:
+              memory: "256Mi"
+              cpu: "250m"
+      restartPolicy: Always

sample-apps/go/k8s/service.yaml

@@ -0,0 +1,51 @@
+# Copyright 2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+apiVersion: v1
+kind: Service
+metadata:
+  name: goshowcase-server
+spec:
+  selector:
+    app: goshowcase-server
+  ports:
+    - port: 80
+      targetPort: 8080
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: goshowcase-server
+spec:
+  selector:
+    matchLabels:
+      app: goshowcase-server
+  template:
+    metadata:
+      labels:
+        app: goshowcase-server
+    spec:
+      containers:
+        - name: goshowcase-server
+          image: "%REGISTRY_LOCATION%-docker.pkg.dev/%GCLOUD_PROJECT%/%CONTAINER_REGISTRY%/go-sample-server:latest"
+          command: ['/server/main']
+          ports:
+            - containerPort: 8080
+          resources:
+            requests:
+              memory: "256Mi"
+              cpu: "250m"
+            limits:
+              memory: "256Mi"
+              cpu: "250m"

sample-apps/go/server/Dockerfile

@@ -0,0 +1,18 @@
+# Copyright 2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+FROM golang:1.19
+WORKDIR /server
+COPY . .
+RUN go build -o main

sample-apps/go/server/go.mod

@@ -0,0 +1,3 @@
+module github.com/GoogleCloudPlatform/opentelemetry-operator-sample/sample-apps/go/server
+
+go 1.20

sample-apps/go/server/main.go

@@ -0,0 +1,33 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+)
+
+func hello(w http.ResponseWriter, _ *http.Request) {
+	fmt.Fprintf(w, "hello\n")
+}
+
+func main() {
+	http.HandleFunc("/hello", hello)
+	err := http.ListenAndServe(":8080", nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+}