NodeJS

Overview

This tutorial will describe how to convert your NodeJS application to docker application for compatibility with FarmStack connector.

Dockerization Process

Create a new file named Dockerfile in the application folder and open in your favorite text editor.

touch Dockerfile

Copy this code into the Dockerfile

First we are going to define the image we are going to use. Here we are using latest alpine image of node to keep the size of NodeJS application small. You can use any image available in the Node's Dockerhub.

FROM node:alpine

Next we will create a directory to copy all our application code inside the image.

# Create app directory
WORKDIR /app

Since we are using node image, node and npm are already installed in this image. We just need to copy our package.json and package-lock.json files.

# Copy package.json and package-lock.json files to image
COPY package*.json ./

RUN npm install

Here, we copy package.json files before copying complete project. This is done to take advantage of Docker layers caching and only install dependencies if the files have changed. You can find more information about this here.

Now we will copy your app's source code to docker image.

# Copy app's source code
COPY . .

Our sample-nodejs app binds to port 8081 so we will map this port to docker daemon by using EXPOSE command. If your app uses any other port, kindly change it

EXPOSE 8081

In this last step, define the command to start your application. Our sample application starts withnpm start command. You can also use a shell script file here which executes to start your server.

ENTRYPOINT ["npm","start"]

This should be your final Dockerfile

Dockerfile

FROM node:alpine
# Create app directory
WORKDIR /app

# Copy package.json and package-lock.json files to image
ADD package*.json ./

RUN npm install

# Copy app's source code
COPY . .

EXPOSE 8081
ENTRYPOINT [ "npm", "start" ]

You can find the final Dockerfile here.

.dockerignore file

Create a .dockerignore file in the same directory as your Dockerfile. Add the following lines to the file:

.dockerignore

node_modules
npm-debug.log
.npm

Next Steps

Install a dockerized application with connector