Docker Compose Example

docker-compose.yaml

# 定義 docker-compose 使用的版本
version: '3'

# 定義兩個 services，一個是 redis-server，另一個是 node-app
# 這兩個 serivces 不需要額外設定，預設就會在同一個 network 內，彼此就能溝通
services:
  redis-server:
    image: 'redis'
  node-app:
    restart: always
    build: . # 根據當前根目錄的 Dockerfile 執行 build
    ports:
      - '8081:8081' # 將 local 的 8081 對應到 container 內的 8081

Dockerfile

FROM node:14-alpine

WORKDIR /app

COPY package.json .
RUN npm install

COPY . .

CMD ["npm", "start"]

index.js

const express = require('express');
const redis = require('redis');
const process = require('process');

const app = express();
const client = redis.createClient({
  host: 'redis-server', // 原本可能會填的是 localhost:6379
  port: 6379,
});

client.set('visits', 0);

app.get('/', (req, res) => {
  process.exit(0);
  client.get('visits', (err, visits) => {
    res.send(`Number of visits is ${visits}`);
    client.set('visits', parseInt(visits, 10) + 1);
  });
});

app.listen(8081, () => {
  console.log('Listening on port 8081');
});

This gist is learned from the course Docker and Kubernetes: The Complete Guide on Udemy.