Use Docker to Serve a Static Ruby Site Locally

Here I am nearly three years after my first post about Creating a Ruby Static Blog and starting from scratch again.

I am using AWS S3 to host my site, but I wanted a simple server running locally to develop against.

Docker proved perfect for this.

Summary

Dockerfile

FROM ruby:2.3.3

ENV APP_HOME /app
RUN mkdir $APP_HOME
WORKDIR $APP_HOME

COPY Gemfile* $APP_HOME/
RUN bundle install

ADD . $APP_HOME
RUN ruby build.rb
CMD ruby -run -e httpd ./_site -p 3000

status.ru

root=Dir.pwd + "/_site"
run Rack::Directory.new("#{root}")

docker build -t blog .

docker run -d -p 8080:3000 --rm blog

Breaking it down

The Dockerfile

FROM ruby:2.3.3

Start with ruby version 2.3.3

ENV APP_HOME /app

Set an environment variable $APP_HOME to /app

RUN mkdir $APP_HOME

Create the /app directory inside the container

WORKDIR $APP_HOME

Change the working directory to /app

COPY Gemfile* $APP_HOME/

Bring your Gemfile and Gemfile.lock into the container

RUN bundle install

Install your gems

ADD . $APP_HOME

Copy your host app directory into the container

At this point you might be wondering why we copied the Gemfile in above when we are just copying it back in again right here.

We want to do that so that we don't have to reinstall our gems every time we want to load an update of our app (which creates a new container layer).

RUN ruby build.rb

Execute the build.rb script inside the container

CMD ruby -run -e httpd ./_site -p 3000

Run a simple Webrick server inside the container. Serve the ./_site directory on port 3000

The webserver

status.ru

This is the config file the webrick server is going to use

root=Dir.pwd + "/_site" run Rack::Directory.new("#{root}")

Inside status.ru and tells the server where to look

Run it

docker build -t blog .

Build the contents of the Dockerfile in an image tagged blog

docker run --name site -d -p 8080:3000 --rm blog

Run a container as a background process -d and forward requests from port 8080 on the host to port 3000 on the container. Remove the container when I exit --rm and use the image blog and name the container site so that it is easy to stop.

http://localhost:8080 and you should see your site.

Commands to know

Verify the blog image is now stored locally

docker images

Verify that site is up and running

docker ps -a

Your content should be available in your browser

localhost:8080 OR 127.0.0.1:8080

Stop the container

docker stop site

Start the container

docker start site

Destroy the container

docker stop site && docker rm site

Remove the blog image

docker rmi blog