Create Docker Container to Run Jekyll

I always faced issues when running jekyll locally, my blog uses jekyll to generate static pages, but every time my os is upgraded or I change my laptop, I always get into trouble of installing/managing ruby version, bundles etc. To my rescue comes the docker, I have created a simple a docker file and script to serve my jekyll pages locally, and it now works like a charm.

I always have been admirer of docker, I tend to use docker more often if have to install any dev app, databases etc or package but still want to keep my machine clean. In this case as well I wanted a consistent mechanism to run my blogs locally.

Dockerfile

The first thing I do is create a simple dockerfile in my Jekyll app. I copy my Gemfile and Gemfile.lock to install the bundles.

FROM jekyll/jekyll:3.8

COPY Gemfile* ./

RUN gem install bundler:2.2.24 && bundle install

ENTRYPOINT [ "jekyll" ]

CMD [ "build" ]

The reason I copied Gemfile is because sometimes the bundle version is different, so now I install the required bundler (in my case its 2.2.24), and install all the dependencies.

Execution Script

Next I created a simple script local_serve.sh to build and serve my code, so that i don’t keep on typing the commands every time.

#!/usr/bin/env bash

set -e

case $1 in
    'prod-build')
        echo "Building docker image of Jekyll"
        docker build -t jekyll .

        echo "Building Jekyll site"    
        docker run \
            --volume="$PWD:/srv/jekyll:Z" \
            -e JEKYLL_ENV=prod \
            -t jekyll \
            build
    ;;
    'build')
        echo "Building docker image of Jekyll"
        docker build -t jekyll .

        echo "Building Jekyll site"    
        docker run \
            --volume="$PWD:/srv/jekyll:Z" \
            -t jekyll
    ;;
    'serve')
    docker run \
            --volume="$PWD:/srv/jekyll:Z" \
            -p 4000:4000 \
            -it jekyll serve
    ;;
esac

In the build command, I am creating the jekyll image. I can mapping the current directory to /srv/jekyll and running my jekyll container to build the site.

In the serve command, I using the same directory to serve my pages at port 4000 and using interactive mode to explicitly invoke serve command.

Run the Jekyll container

Before we proceed do not forget to give executable permission to local_service.sh

$ chmod a+x local_serve.sh

So, first thing to do is to build our Jekyll app so that all the dependencies are downloaded. We will just run

$ ./local_serve.sh build

Once the dependencies are downloaded, now lets start our Jekyll server

$ ./local_serve.sh serve

And we can see the server started

ruby 2.6.3p62 (2019-04-16 revision 67580) [x86_64-linux-musl]
Configuration file: /srv/jekyll/_config.yml
            Source: /srv/jekyll
       Destination: /srv/jekyll/_site
 Incremental build: disabled. Enable with --incremental
      Generating... 
       Jekyll Feed: Generating feed for posts
   GitHub Metadata: No GitHub API authentication could be found. Some fields may be missing or have incorrect data.
                    done in 17.778 seconds.
 Auto-regeneration: enabled for '/srv/jekyll'
    Server address: http://0.0.0.0:4000/
  Server running... press ctrl-c to stop.

Enjoy running Jekyll locally without installing ruby or jekyll directly on your system.

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