Node.js

The LeySerKids Node.js docker image.

Table of Contents

• What is Node.js?
• How to use this image
  • Create a Dockerfile in your Node.js app project
    • Notes
  • Best Practices
  • Run a single Node.js script
  • Verbosity
    • Dockerfile
    • Docker Run
    • NPM run
• Image Variants
  • node:<version>
• License
• Supported Docker versions

What is Node.js?

Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

See: http://nodejs.org

How to use this image

Create a Dockerfile in your Node.js app project

# specify the node base image with your desired version node:<version>
FROM node:6
# replace this with your application's default port
EXPOSE 8888

You can then build and run the Docker image:

$ docker build -t my-nodejs-app .
$ docker run -it --rm --name my-running-app my-nodejs-app

If you prefer Docker Compose:

version: "2"
services:
  node:
    image: "node:8"
    environment:
      - NODE_ENV=production
    volumes:
      - ./:/usr/src/app
    expose:
      - "8080"

You can then run using Docker Compose:

$ docker-compose up -d

Notes

The image assumes that your application has a file named package.json listing its dependencies and defining its start script.

It also assumes that you have a file named .dockerignore otherwise it will copy your local npm modules:

node_modules

Best Practices

We have assembled a Best Practices Guide for those using these images on a daily basis.

Run a single Node.js script

For many simple, single file projects, you may find it inconvenient to write a complete Dockerfile. In such cases, you can run a Node.js script by using the Node.js Docker image directly:

$ docker run -it --rm --name my-running-script -v "$PWD":/usr/src/app -w /usr/src/app node:4 node your-daemon-or-script.js

Verbosity

By default the Node.js Docker Image has npm log verbosity set to info instead of the default warn. This is because of the way Docker is isolated from the host operating system and you are not guaranteed to be able to retrieve the npm-debug.log file when npm fails.

When npm fails, it writes it's verbose log to a log file inside the container. If npm fails during an install when building a Docker Image with the docker build command, this log file will become inaccessible when Docker exits.

The Docker Working Group have chosen to be overly verbose during a build to provide an easy audit trail when install fails. If you prefer npm to be less verbose you can easily reset the verbosity of npm using the following techniques:

Dockerfile

If you create your own Dockerfile which inherits from the node image you can simply use ENV to override NPM_CONFIG_LOGLEVEL.

FROM node
ENV NPM_CONFIG_LOGLEVEL warn
...

Docker Run

If you run the node image using docker run you can use the -e flag to override NPM_CONFIG_LOGLEVEL.

$ docker run -e NPM_CONFIG_LOGLEVEL=warn node ...

NPM run

If you are running npm commands you can use --loglevel to control the verbosity of the output.

$ docker run node npm --loglevel=warn ...

Image Variants

The node images come in many flavors, each designed for a specific use case. All of the images contain pre-installed versions of node, npm, and yarn. For each supported architecutre, the supported variants are different. In the file: architectures, it lists all supported variants for all of the architecures that we support now.

node:<version>

This is the defacto image. If you are unsure about what your needs are, you probably want to use this one. It is designed to be used both as a throw away container (mount your source code and start the container to start your app), as well as the base to build other images off of. This tag is based off of buildpack-deps. buildpack-deps is designed for the average user of docker who has many images on their system. It, by design, has a large number of extremely common Debian packages. This reduces the number of packages that images that derive from it need to install, thus reducing the overall size of all images on your system.

License

License information for the software contained in this image. License information for the Node.js Docker project.

Supported Docker versions

This image is officially supported on Docker version 1.9.1.

Support for older versions (down to 1.6) is provided on a best-effort basis.

Please see the Docker installation documentation for details on how to upgrade your Docker daemon.