Before building a Winston logger image on Docker, you will need to install Docker and install NodeJS, and you will probably want to have built the Sails image.

A Docker image contains the code used to create a Docker container, such as creating a Nginx web server, or a mySQL server, or a home grown app, and the list goes on. In this way, an image is like a template used to create a container. An image is kind of like a virtual machine, but much more light weight, using significantly less storage a memory (containers are usually megabytes in size).

Create a file named Dockerfile.

touch /usr/local/docker/sails/Dockerfile

Append the following to Dockerfile. This will create an image using the latest version of the Winston logger.

FROM node:lts
RUN npm install winston --global

The docker build command can be used to build the image. In this example, /usr/local/docker/sails is the directory that contains the Dockerfile.

docker build --tag nodejs/winston:latest /usr/local/docker/sails

If the install is successful, something like this should be returned.

Successfully built fb60d5e3e7c8
Successfully tagged winston:latest

And the docker images command should return something like this.

~]# docker images
REPOSITORY      TAG     IMAGE ID      CREATED             SIZE
nodejs/sails    latest  fb60d5e3e7c8  2 minutes ago       947MB
nodejs/winston  latest  406e27a874e7  About a minute ago  973MB
node            lts     7528ad312b56  6 days ago          944MB