PP-11224: Add Dockerfile, config, and unit test workflow

.github/dependabot.yml

@@ -21,3 +21,13 @@ updates:
     - dependencies
     - govuk-pay
     - github_actions
+- package-ecosystem: npm
+  directory: "/tests/node_service"
+  schedule:
+    interval: daily
+    time: "03:00"
+  open-pull-requests-limit: 0
+  labels:
+  - dependencies
+  - govuk-pay
+  - javascript

.github/workflows/post-merge.yml

@@ -0,0 +1,22 @@
+name: Post Merge
+
+on:
+  push:
+    branches:
+      - main
+    paths-ignore:
+      - '.github/**'
+
+permissions:
+  contents: read
+
+jobs:
+  tests:
+    uses: ./.github/workflows/run-tests.yml
+
+  tag-release:
+    needs:
+      - tests
+    permissions:
+      contents: write
+    uses: alphagov/pay-ci/.github/workflows/_create-alpha-release-tag.yml@master

.github/workflows/run-tests.yml

@@ -0,0 +1,32 @@
+name: Build and test
+
+on:
+  workflow_call:
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  detect-secrets:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Git checkout
+        uses: actions/checkout@8e5e7e5ab8b370d6c329ec480221332ada57f0ab
+      - name: Detect secrets
+        uses: alphagov/pay-ci/actions/detect-secrets@master
+
+  build-and-test:
+    name: Container Build Tests
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@8e5e7e5ab8b370d6c329ec480221332ada57f0ab
+      - name: Docker build
+        run: |
+          docker build -t pay-adot:github-tests .
+      - name: Run tests
+        working-directory: tests/
+        run: ./test.sh
+
+

Dockerfile

@@ -0,0 +1,5 @@
+FROM amazon/aws-otel-collector:v0.30.0
+
+COPY config.yml /etc/ecs/govuk-pay-adot-sidecar-config.yaml
+
+CMD ["--config=/etc/ecs/govuk-pay-adot-sidecar-config.yaml"]

config.yml

@@ -0,0 +1,38 @@
+receivers:
+  prometheus:
+    config:
+      global:
+        scrape_interval: 15s
+        scrape_timeout: 10s
+      scrape_configs:
+      - job_name: "adot-sidecar-scrape-application"
+        static_configs:
+        - targets: [ "127.0.0.1:$APPLICATION_PORT" ]
+        honor_labels: true
+        honor_timestamps: true
+
+processors:
+
+exporters:
+  prometheusremotewrite:
+    endpoint: $PROMETHEUS_ENDPOINT_URL
+    resource_to_telemetry_conversion:
+        enabled: false
+    auth:
+      authenticator: sigv4auth
+  logging:
+    loglevel: info
+
+extensions:
+  sigv4auth:
+    region: $AWS_REGION
+    service: aps
+    assume_role:
+      arn: $PROMETHEUS_WRITE_ASSUME_ROLE_ARN
+
+service:
+  extensions: [sigv4auth]
+  pipelines:
+    metrics/application:
+      receivers: [prometheus]
+      exporters: [logging, prometheusremotewrite]

tests/docker-compose.yml

@@ -0,0 +1,39 @@
+version: "3"
+services:
+  test-app:
+    build: node_service/
+    expose:
+      - 3000
+    ports:
+      - 3000:3000
+    healthcheck:
+      test: ["CMD", "wget", "-O", "/dev/null", "-q", "http://localhost:3000/metrics"]
+      interval: 1s
+      timeout: 10s
+      retries: 30
+
+  adot-sidecar:
+    build: ../.
+    volumes:
+      - "./test-config.yml:/etc/ecs/govuk-pay-adot-sidecar-config.yaml"
+    depends_on:
+      - prometheus
+      - test-app
+    environment:
+      - APPLICATION_PORT=3000
+      - PROMETHEUS_REMOTE_WRITE_URL=http://prometheus:9090/api/v1/write
+
+  prometheus:
+    image: prom/prometheus:v2.45.0
+    expose:
+      - 9090
+    ports:
+      - 9090:9090
+    command:
+      - --web.enable-remote-write-receiver
+      - --config.file=/etc/prometheus/prometheus.yml
+    healthcheck:
+      test: ["CMD", "wget", "-O", "/dev/null", "-q", "http://localhost:9090/-/ready"]
+      interval: 5s
+      timeout: 10s
+      retries: 30

tests/node_service/.gitignore

@@ -0,0 +1 @@
+node_modules/

tests/node_service/Dockerfile

@@ -0,0 +1,16 @@
+FROM node:20-alpine
+
+RUN apk add --no-cache tini
+
+WORKDIR /app
+
+COPY package*.json ./
+RUN npm ci --no-progress --omit=dev
+
+COPY ./index.mjs index.mjs
+
+EXPOSE 3000
+
+ENTRYPOINT ["/sbin/tini", "--"]
+
+CMD ["node", "index.mjs"]

tests/node_service/index.mjs

@@ -0,0 +1,67 @@
+import promClient from 'prom-client'
+import express from 'express'
+
+promClient.collectDefaultMetrics({ timeout: 10000 })
+promClient.register.metrics().then(str => console.log('Metrics registered'))
+
+function defaultLabels() {
+  return {
+    ecsClusterName: "local-test",
+    ecsServiceName: "test-node-app",
+    awsAccountName: "local",
+  }
+}
+
+try {
+  promClient.register.setDefaultLabels(defaultLabels());
+} catch (ex) {
+  const labels = {}
+  console.log(`Failed to get labels ${ex}`)
+}
+
+const counters = {
+  index: new promClient.Counter({
+    name: 'page_count_index',
+    help: 'Count of hits to the index page',
+  }),
+  foo: new promClient.Counter({
+    name: 'page_count_foo',
+    help: 'Count of hits to the foo page',
+  }),
+  metrics: new promClient.Counter({
+    name: 'page_count_metrics',
+    help: 'Count of hits to the metrics page',
+  }),
+
+}
+
+const app = express()
+const port = 3000
+
+app.get('/', (req, res) => {
+  counters.index.inc()
+  console.log('GET /')
+  res.send('Hello World!')
+})
+
+app.get('/foo', (req, res) => {
+  counters.foo.inc()
+  console.log('GET /foo')
+  res.send('Foo woo hoo')
+})
+
+app.get('/metrics', async (req, res) =>  {
+  counters.metrics.inc()
+  console.log('GET /metrics')
+  try {
+    res.set('Content-Type', promClient.register.contentType)
+    const metrics = await promClient.register.metrics()
+    res.end(metrics)
+  } catch (ex) {
+    res.status(500).end(ex)
+  }
+})
+
+app.listen(port, () => {
+  console.log(`Example app listening on port ${port}`)
+})