An introduction to how to efficiently deploy Node.js applications using Docker

A reasonable and efficient deployment solution can not only achieve rapid upgrades, smooth switching, load balancing, application isolation and other deployment features, but also come with a set of mature and stable monitoring.

kubernetes Treat Node application as a black box of server-side application, which perfectly matches the above conditions. More and more teams are deploying node on k8s. [Recommended video tutorials: node js tutorial, Docker video tutorial]

But before that, you need to run the Node application on a Docker container. This is also The subject of this chapter.

Regarding front-end deployment on docker, the author has written several articles:

1. How to deploy the front-end in docker
2. Front-end deployment Prview and Production
3. The development process of front-end deployment

A simple Node application

index.js

A hello, world version of Node Web App

const http = require('http')

const app = async (req, res) => {
  res.end('hello, world')
}

http.createServer(app).listen(3000, () => console.log(3000))

package.json

Configurationnpm start to start the application

"scripts": {
  "start": "node index.js"
},

But this is just the simplest Node application. In the real environment, there are various data storage and scheduled task scheduling, etc., let’s leave them aside for now. Don't talk about it, that's enough.

For a slightly more complex Node application, you can check out Shanyue's project whoami: A simplest example of serverless and dockerize.

NODE_ENV=production

In the production environment, there is no need to install the dependencies in devDependecies. When the NODE_ENV environment variable is set to production, devDep will be skipped. .

# 通过设置环境变量，只安装生产环境依赖
$ NODE_ENV=production npm ci

# 通过显式指定 flag，只安装生产环境依赖
$ npm ci --production

On the other hand, some third-party modules will make some unexpected configurations based on the NODE_ENV environment variable. Therefore, pay attention to the configuration of this environment variable in the production environment.

Simple deployment of a Node application

A typical server-oriented Node application runs like this:

1. npm install
2. npm run config, pull the configuration from the configuration service (consul/vault), such as the database and cached account password. At this time, the build server requires configuration service permissions
3. npm run migrate, database migration script, performs database table column and row changes. At this time, the build server requires database access permission
4. npm start, starts a Node service

Translate the running steps into Dockerfile:

# 选择一个体积小的镜像 (~5MB)
FROM node:12-alpine

# 环境变量设置为生产环境
ENV NODE_ENV production

WORKDIR /code

# 更好的根据 Image Layer 利用缓存
ADD package.json package-lock.json /code
RUN npm ci

ADD . /code

# 配置服务及数据库迁移
RUN npm run config --if-present && npm run migrate --if-present

EXPOSE 3000
CMD npm start

This is enough for most Node applications. If you want to improve, you can go to the next multi-stage build

node-gyp and Native Addon

There may be some Native Addons in Node, they are compiled through node-gyp, and it depends on python,make and g .

$ apk --no-cache add python make g++

In the image construction with compilation process, source files and build tools will cause a waste of space. Space can be efficiently utilized with the multi-stage build of the image. Go App and FE App are also built to follow this rule.

• Building Go applications in multiple stages
• Building front-end applications in multiple stages

Building Node applications When mirroring, the first layer of mirroring is used to construct node_modules.

# 选择一个体积小的镜像 (~5MB)
FROM node:12-alpine as builder

# 环境变量设置为生产环境
ENV NODE_ENV production

# 更好的根据 Image Layer 利用缓存
ADD package.json package-lock.json ./
RUN npm ci

# 多阶段构建之第二阶段
# 多阶段构建之第二阶段
# 多阶段构建之第二阶段
FROM node:12-alpine

WORKDIR /code
ENV NODE_ENV production

ADD . .
COPY --from=builder node_modules node_modules
# 配置服务及数据库迁移
RUN npm run config --if-present && npm run migrate --if-present

EXPOSE 3000
CMD npm start

Related articles

1. N-API and getting started with writing C addons for Node.js
2. ##Using Docker for Node.js in Development and Production

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