title: Dockerizing a Node.js web app
layout: docs.hbs
Dockerizing a Node.js web app
The goal of this example is to show you how to get a Node.js application into a Docker container. It assumes you have a working Docker installation and a basic understanding of how a Node.js application is structured.
這個列子的目的是告訴你怎樣將一個 Node.js應用放到Docker容器中。它假定你有一個工作中的Docker 安裝并且基本了解如何構建Node.js應用。
In the first part of this guide we will create a simple web application in Node.js, then we will build a Docker image for that application, and lastly we will run the image as container.
在本指南的第一部分我們將創建一個簡單的Node.js web應用，然后為應用建一個Docker image，最后作為容器運行 image。
Docker allows you to package an application with all of its dependencies into a standardized unit, called a container, for software development. A container is a stripped-to-basics version of a Linux operating system. An image is software you load into a container.
Docker 允許你將包含所有依賴的應用打包到一個被稱為container(容器)的標準單位中，為軟件開發。一個container是剝離基本版本的Linux操作系統。一個Image是你裝入容器的軟件。
Create the Node.js app
創建Node.js應用
First, create a new directory where all the files would live. In this directory create a package.json file that describes your app and its dependencies:
首先，創建一個新目錄為所有文件的根。在這個目錄創建一個package.json文件描述應用和它的依賴：
{
"name": "docker_web_app",
"version": "1.0.0",
"description": "Node.js on Docker",
"author": "First Last <first.last@example.com>",
"main": "server.js",
"dependencies": {
"express": "^4.13.3"
}
}
Then, create an server.js file that defines a web app using the
Express.js framework:
然后，創建server.js文件定義web應用使用Express.js 框架：
'use strict';
const express = require('express');
// Constants
const PORT = 8080;
// App
const app = express();
app.get('/', function (req, res) {
res.send('Hello world\n');
});
app.listen(PORT);
console.log('Running on http://localhost:' + PORT);
In the next steps, we'll look at how you can run this app inside a Docker container using the official Docker image. First, you'll need to build a Docker image of your app.
在下一步，我們將看看如何在一個Docker容器中使用官方Docker image運行這個應用。首先，你需要在應用中建一個Docker image。
Creating a Dockerfile
Create an empty file called Dockerfile:
創建空文件名叫Dockerfile:
touch Dockerfile
Open the Dockerfile in your favorite text editor
用你喜歡的文本編輯器打開Dockerfile
The first thing we need to do is define from what image we want to build from.
第一件事我們要定義我們想要從什么 image 建造。
Here we will use the latest LTS (long term support) version argon of nodeavailable from the Docker Hub:
這里我們將使用最后 LTS（長期支持）版本 argon of node可從Docker Hub得到：
FROM node:argon
Next we create a directory to hold the application code inside the image, this will be the working directory for your application:
下一步我們在image中創建目錄來存放應用代碼，這將是你應用的工作目錄：
# Create app directory
RUN mkdir -p /usr/src/app
WORKDIR /usr/src/app
This image comes with Node.js and NPM already installed so the next thing we need to do is to install your app dependencies using the npm binary:
這個image 依賴Node.js和NPM已經安裝，所以我們 下一步需要做的事情就是安裝你的應用程序依賴性使用 npm 二進制文件：
# Install app dependencies
COPY package.json /usr/src/app/
RUN npm install
To bundle your app's source code inside the Docker image, use the COPYinstruction:
使用COPY指令復制應用代碼到Docker image中。
# Bundle app source
COPY . /usr/src/app
Your app binds to port 8080 so you'll use the EXPOSE instruction to have it mapped by the docker daemon:
你的app綁定到8080端口，所以使用EXPOSE指令映射這個端口到 docker 守護進程：
EXPOSE 8080
Last but not least, define the command to run your app using CMD which defines your runtime. Here we will use the basic npm start which will run node server.js to start your server:
最后，命令CMD定義你的運行時運行應用。這里我們使用基本的npm start將運行node server.js來開啟你的服務：
CMD [ "npm", "start" ]
Your Dockerfile should now look like this:
你的Dockerfile 應該像這樣：
FROM node:argon
# Create app directory
RUN mkdir -p /usr/src/app
WORKDIR /usr/src/app
# Install app dependencies
COPY package.json /usr/src/app/
RUN npm install
# Bundle app source
COPY . /usr/src/app
EXPOSE 8080
CMD [ "npm", "start" ]
Building your image
建立你的 image
Go to the directory that has your Dockerfile and run the following command to build the Docker image. The -t flag lets you tag your image so it's easier to find later using the docker images command:
去有Dockerfile的目錄運行下面的命令建立Docker image。-t 標志你的image方便你以后查找使用docker images 。
$ docker build -t <your username>/node-web-app .
Your image will now be listed by Docker:
你的image可以顯示在Docker列表
$ docker images
# Example
REPOSITORY TAG ID CREATED
node argon 539c0211cd76 3 weeks ago
<your username>/node-web-app latest d64d3505b0d2 1 minute ago
Run the image
運行image
Running your image with -d runs the container in detached mode, leaving the container running in the background. The -p flag redirects a public port to a private port inside the container. Run the image you previously built:
運行您的image , -d運行在分離模式的容器，離開的容器中運行在后臺。-p將公共端口到一個私有端口。運行你先前建立的image：
$ docker run -p 49160:8080 -d <your username>/node-web-app
Print the output of your app:
# Get container ID
$ docker ps
# Print app output
$ docker logs <container id>
# Example
Running on http://localhost:8080
If you need to go inside the container you can use the exec command:
如果你需要進入容器可以使用exec命令：
# Enter the container
$ docker exec -it <container id> /bin/bash
Test
To test your app, get the port of your app that Docker mapped:
要測試你的應用，得到應用的Docker端口映射
$ docker ps
# Example
ID IMAGE COMMAND ... PORTS
ecce33b30ebf <your username>/node-web-app:latest npm start ... 49160->8080
In the example above, Docker mapped the 8080 port inside of the container to the port 49160 on your machine.
Now you can call your app using curl (install if needed via: sudo apt-get install curl):
$ curl -i localhost:49160
HTTP/1.1 200 OK
X-Powered-By: Express
Content-Type: text/html; charset=utf-8
Content-Length: 12
Date: Sun, 02 Jun 2013 03:53:22 GMT
Connection: keep-alive
Hello world
We hope this tutorial helped you get up and running a simple Node.js application on Docker.
You can find more information about Docker and Node.js on Docker in the following places:
