Continuing this short series of writing a simple echo service web API along with the docker and k8s requirements, we’re now going to turn our attention to a Node implementation.<\/p>\n
Add the file app.ts to the \/src folder with the following content<\/p>\n
\r\nimport express, { Request, Response } from 'express';\r\nimport bodyParser from 'body-parser';\r\n\r\nconst app = express();\r\nconst PORT = process.env.PORT || 8080;\r\n\r\napp.use(bodyParser.json());\r\n\r\n\r\napp.get('\/echo', (req: Request, res: Response) => {\r\n const queryParams = req.query;\r\n res.type('text\/plain');\r\n res.send(`Node Echo: ${queryParams.text}`);\r\n});\r\n\r\napp.get('\/livez', (_req: Request, res: Response) => {\r\n res.sendStatus(200);\r\n});\r\n\r\napp.get('\/readyz', async (_req: Request, res: Response) => {\r\n try {\r\n res.sendStatus(200);\r\n } catch (err) {\r\n res.status(503).send('Service not ready');\r\n }\r\n});\r\n\r\napp.listen(PORT, () => {\r\n console.log(`Echo service is live at http:\/\/localhost:${PORT}`);\r\n});\r\n<\/pre>\nDockerfile<\/strong><\/p>\nNext up we need to create our Dockerfile<\/p>\n
\r\nFROM node:24-alpine\r\n\r\nWORKDIR \/app\r\n\r\nCOPY package.json package-lock.json* tsconfig.json .\/\r\n\r\nRUN npm install\r\n\r\nCOPY src .\/src\r\n\r\n#RUN npx tsc\r\n\r\nEXPOSE 8080\r\n\r\nCMD ["npx", "ts-node", "src\/app.ts"]\r\n<\/pre>\nNote: In Linux port 80 might be locked down, hence we use port 8080 by default.<\/em><\/p>\nTo build this, run <\/p>\n
\r\ndocker build -t putridparrot.echo_service:v1 .\r\n<\/pre>\nDon’t forget to change the name to your preferred name.<\/em><\/p>\nand to test this, run<\/p>\n
\r\ndocker run -p 8080:8080 putridparrot.echo_service:v1\r\n<\/pre>\nKubernetes<\/strong><\/p>\nIf all wen well we’ve not tested our application and see it working from a docker image, so now we need to create the deployment etc. for Kubernete’s. Let’s assume you’ve pushed you image to Docker or another container registry such as Azure – I’m call my container registry putridparrotreg<\/em>.<\/p>\nI’m also not going to use helm at this point as I just want a (relatively) simple yaml file to run from kubectl, so create a deployment.yaml file, we’ll store all the configurations, deployment, service and ingress in this one file jus for simplicity.<\/p>\n
\r\napiVersion: apps\/v1\r\nkind: Deployment\r\nmetadata:\r\n name: echo\r\n namespace: dev\r\n labels:\r\n app: echo\r\nspec:\r\n replicas: 1\r\n selector:\r\n matchLabels:\r\n app: echo\r\n template:\r\n metadata:\r\n labels:\r\n app: echo\r\n spec:\r\n containers:\r\n - name: echo\r\n image: putridparrotreg\/putridparrot.echo_service:v1\r\n ports:\r\n - containerPort: 8080\r\n resources:\r\n requests:\r\n memory: "100Mi"\r\n cpu: "100m"\r\n limits:\r\n memory: "200Mi"\r\n cpu: "200m"\r\n livenessProbe:\r\n httpGet:\r\n path: \/livez\r\n port: 8080\r\n initialDelaySeconds: 30\r\n periodSeconds: 10\r\n readinessProbe:\r\n httpGet:\r\n path: \/readyz\r\n port: 8080\r\n initialDelaySeconds: 5\r\n periodSeconds: 5\r\n\r\n---\r\napiVersion: v1\r\nkind: Service\r\nmetadata:\r\n name: echo_service\r\n namespace: dev\r\n labels:\r\n app: echo\r\nspec:\r\n type: ClusterIP\r\n selector:\r\n app: echo \r\n ports:\r\n - name: http\r\n port: 80\r\n targetPort: 8080\r\n protocol: TCP\r\n---\r\napiVersion: networking.k8s.io\/v1\r\nkind: Ingress\r\nmetadata:\r\n name: echo-ingress\r\n namespace: dev\r\n annotations:\r\n kubernetes.io\/ingress.class: "nginx"\r\n nginx.ingress.kubernetes.io\/rewrite-target: \/\r\nspec:\r\n rules:\r\n - host: mydomain.com\r\n http:\r\n paths:\r\n - path: \/\r\n pathType: Prefix\r\n backend:\r\n service:\r\n name: echo_service\r\n port:\r\n number: 80\r\n<\/pre>\n