# Docker教學
## 安裝
OSX:
> windows版本的docker建議可以使用kitemantic整合環境
windows:
windows使用kitemantic後點選右下角的DOCKER CLI
## 以下為Docker執行Redis與Node.js server並分別expose兩個PORT的範例
1.新增package.json
```
{
"name": "docker_web_app",
"version": "1.0.0",
"description": "Node.js on Docker",
"author": "First Last ",
"main": "server.js",
"scripts": {
"start": "node server.js"
},
"dependencies": {
"express": "^4.13.3"
}
}
```
2.server.js
```javascript
'use strict';
const express = require('express');
// Constants
const PORT = 8080;
const HOST = '0.0.0.0';
// App
const app = express();
app.get('/', (req, res) => {
res.send('Hello world\n');
});
app.listen(PORT, HOST);
console.log(`Running on http://${HOST}:${PORT}`);
```
3.Dockerfile
```
FROM node:boron
WORKDIR /usr/src/app
RUN apt-get update && apt-get install -y redis-server
COPY package.json .
RUN npm install
# Bundle app source
COPY . .
EXPOSE 8080 6379
CMD [ "npm", "start" ]
```
4\.
建立image
(-t 為tag 的意思即為這個image的名字)
```
docker build -t test/node-web-app .
```
5\.
執行image
(意思為把Node.js server之8080port開放給外面電腦的49160，與開放Redis的6379給外面電腦的49161)
> 開啟瀏覽器localhost:49160即可看到
```
docker run -p 49160:8080 49161:6379 test/node-web-app
```
6.連線到Redis
記得先進去container開啟Redis-server
```
docker ps
```
之後會顯示如下
```
CONTAINER ID IMAGE COMMAND CREATED STATUS
PORTS NxAMESe
c7b4df8ebffb test/node-web-app "npm start" 11 minutes ago Up 11 minu
```
然後用exec的方法進入docker的Process 之cli
```
docker exec -it c7b4df8ebffb /bin/bash
```
啟動Redis
```
redis-server
```
7.之後寫一個Node.js的程式來連Redis
```javascript
const redis = require('redis')
RDS_PORT = 49161,
RDS_HOST = '127.0.0.1',
client = redis.createClient(RDS_PORT, RDS_HOST,{});
client.on('ready', (res) => {
console.log('ready');
})
```
## 把image搬到其他電腦
把最後面參數名字的image(剛才tag名稱)存成 dockerImage 壓縮檔
```
docker save -o ./dockerImage test/node-web-app
```
然後把此image壓縮檔移到在別台電腦及可讀取
```
docker load -i ./dockerImage
```
## PUSH Image到Docker Hub
1.先到註冊帳號
2.Create new repository
3.登入
```
docker login --username=<你的Dockerhub username> --password=<你的docker Hub密碼>
```
4.查看你要push的image的ID
```
docker images
```
5.把ID配上你的repository名稱
```
docker tag bb38976d03cf yourhubusername/repositoryName
```
6.推送
```
docker push yourhubusername/repositoryName
```
## 減少 Build 後 Image 檔案大小
使用 multistage build
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