Node MSA

Authentication

Node Cookie Session: use ^1.4.0 version

Udemy Course on cookie-session

::: warning Don't use cookie-session 2.0 :::

Error Handling

warning

Needs to be handled consistently

Use an Abstract Error Class to simplify checking in the validation middleware. The benefit of using an abstract class over an interface is that the abstract class will persist through to javascript.

import { Request, Response, NextFunction } from 'express';
import { CustomError } from '../errors/custom-error';

export const errorHander = (err: Error, req: Request, res: Response, next: NextFunction) => {
  if (err instanceof CustomError) {
    return res.status(err.statusCode).send({ errors: err.serializeErrors() });
  }

  res.status(400).send({
    errors: [{ message: 'Something went wrong' }],
  });
};

New Service

Step 1

Create a src folder

Step 2

Copy

• .dockerignore
• Dockerfile
• package.json
• tsconfig.json
• src/test
• src/index.ts
• src/app.ts

Step 3

Replace references to the old service with the new service. For example auth with tickets.

Delete references to the copied service's routes.

Step 4

npm install

Step 5

In the folder of the new service!!!

docker build -t stackmates/<new-service-name> .
docker push stackmates/<new-service-name>

Step 6

Setup k8s file for deployment

In the k8s folder create a copy of the depl for the original service. Example auth-depl.yaml to tickets-depl.yaml.

Then replace references to the old service with the new service name.

Step 7

Update skaffold.yaml to automatically sync changes

Copy the existing reference services config then update with the new service name.

- image: stackmates/<new-service-name>
  context: <new-service-name>
  docker:
    dockerfile: Dockerfile
  sync:
    manual:
      - src: 'src/**/*.ts'
        dest: .

Check src is correct for code structure of the service.

tip

Make sure indentation is correct

Step 8

Write k8s for DB deployment and service layer.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: <new-service-name>-mongo-depl
spec:
  replicas: 1
  selector:
    matchLabels:
      app: <new-service-name>-mongo
  template:
    metadata:
      labels:
        app: <new-service-name>-mongo
    spec:
      containers:
        - name: <new-service-name>-mongo
          image: mongo
---
apiVersion: v1
kind: Service
metadata:
  name: <new-service-name>-mongo-srv
spec:
  selector:
    app: <new-service-name>-mongo
  ports:
    - name: db
      protocol: TCP
      port: 27017
      targetPort: 27017

Step 9

Check skaffold build is working correctly.

skaffold dev

Any issues repeat 5.

Step 10

Setup the services routes.

Some common test cases.

xit('has a route handler at </api/--> to handle post requests', async () => {});
xit('can only be accessed if the user is authenticated', async () => {});
xit('returns an error if an invalid <fieldOne> is provided', async () => {});
xit('returns an error if an invalid <fieldTwo> is provided', async () => {});
xit('creates a <new-service-item> with valid inputs', async () => {});

Step 11

Add new routes then setup the ingress-srv.yaml file to route the traffic.

• Service layer

Data Management

Eventual consistency, how to manage data versioning

Links

URL	Notes
Nx and Node Microservices