Travis CI
You can easily test your website build against one or more versions of Ruby. The following guide will show you how to set up a free build environment on Travis, with GitHub integration for pull requests.
1. Enabling Travis and GitHub
Enabling Travis builds for your GitHub repository is pretty simple:
- Go to your profile on travis-ci.org: https://travis-ci.org/profile/username
- Find the repository for which you’re interested in enabling builds.
- Flick the repository switch on so that it turns blue.
- Optionally configure the build by clicking on the gear icon. Further configuration happens via your
.travis.yml
file. More details below.
2. The Test Script
The simplest test script simply runs jekyll build
and ensures that Jekyll doesn’t fail to build the site. It doesn’t check the resulting site, but it does ensure things are built properly.
When testing Jekyll output, there is no better tool than html-proofer. This tool checks your resulting site to ensure all links and images exist. Utilize it either with the convenient htmlproofer
command-line executable, or write a Ruby script which utilizes the gem.
Save the commands you want to run and succeed in a file: ./script/cibuild
The HTML Proofer Executable
#!/usr/bin/env bash set -e # halt script on error bundle exec jekyll build bundle exec htmlproofer ./_site
Some options can be specified via command-line switches. Check out the html-proofer
README for more information about these switches, or run htmlproofer --help
locally.
For example to avoid testing external sites, use this command:
bundle exec htmlproofer ./_site --disable-external
The HTML Proofer Library
You can also invoke html-proofer
in Ruby scripts (e.g. in a Rakefile):
#!/usr/bin/env ruby require 'html-proofer' HTMLProofer.check_directory("./_site").run
Options are given as a second argument to .new
, and are encoded in a symbol-keyed Ruby Hash. For more information about the configuration options, check out html-proofer
’s README file.
3. Configuring Your Travis Builds
This file is used to configure your Travis builds. Because Jekyll is built with Ruby and requires RubyGems to install, we use the Ruby language build environment. Below is a sample .travis.yml
file, followed by an explanation of each line.
Note: You will need a Gemfile as well, Travis will automatically install the dependencies based on the referenced gems:
source "https://rubygems.org" gem "jekyll" gem "html-proofer"
Your .travis.yml
file should look like this:
language: ruby rvm: - 2.3.3 before_script: - chmod +x ./script/cibuild # or do this locally and commit # Assume bundler is being used, therefore # the `install` step will run `bundle install` by default. script: ./script/cibuild # branch whitelist, only for GitHub Pages branches: only: - gh-pages # test the gh-pages branch - /pages-(.*)/ # test every branch which starts with "pages-" env: global: - NOKOGIRI_USE_SYSTEM_LIBRARIES=true # speeds up installation of html-proofer sudo: false # route your build to the container-based infrastructure for a faster build
Ok, now for an explanation of each line:
language: ruby
This line tells Travis to use a Ruby build container. It gives your script access to Bundler, RubyGems, and a Ruby runtime.
rvm: - 2.3.3
RVM is a popular Ruby Version Manager (like rbenv, chruby, etc). This directive tells Travis the Ruby version to use when running your test script.
before_script: - chmod +x ./script/cibuild
The build script file needs to have the executable attribute set or Travis will fail with a permission denied error. You can also run this locally and commit the permissions directly, thus rendering this step irrelevant.
script: ./script/cibuild
Travis allows you to run any arbitrary shell script to test your site. One convention is to put all scripts for your project in the script
directory, and to call your test script cibuild
. This line is completely customizable. If your script won’t change much, you can write your test incantation here directly:
install: gem install jekyll html-proofer script: jekyll build && htmlproofer ./_site
The script
directive can be absolutely any valid shell command.
# branch whitelist, only for GitHub Pages branches: only: - gh-pages # test the gh-pages branch - /pages-(.*)/ # test every branch which starts with "pages-"
You want to ensure the Travis builds for your site are being run only on the branch or branches which contain your site. One means of ensuring this isolation is including a branch whitelist in your Travis configuration file. By specifying the gh-pages
branch, you will ensure the associated test script (discussed above) is only executed on site branches. If you use a pull request flow for proposing changes, you may wish to enforce a convention for your builds such that all branches containing edits are prefixed, exemplified above with the /pages-(.*)/
regular expression.
The branches
directive is completely optional. Travis will build from every push to any branch of your repo if leave it out.
env: global: - NOKOGIRI_USE_SYSTEM_LIBRARIES=true # speeds up installation of html-proofer
Using html-proofer
? You’ll want this environment variable. Nokogiri, used to parse HTML files in your compiled site, comes bundled with libraries which it must compile each time it is installed. Luckily, you can dramatically decrease the install time of Nokogiri by setting the environment variable NOKOGIRI_USE_SYSTEM_LIBRARIES
to true
.
Be sure to exclude
vendor
from your_config.yml
Travis bundles all gems in the
vendor
directory on its build servers, which Jekyll will mistakenly read and explode on.
exclude: [vendor]
By default you should supply the sudo: false
command to Travis. This command explicitly tells Travis to run your build on Travis’s container-based infrastructure. Running on the container-based infrastructure can often times speed up your build. If you have any trouble with your build, or if your build does need sudo
access, modify the line to sudo: required
.
sudo: false
Troubleshooting
Travis error: “You are trying to install in deployment mode after changing your Gemfile. Run bundle install elsewhere and add the updated Gemfile.lock to version control.”
Workaround: Either run bundle install
locally and commit your changes to Gemfile.lock
, or remove the Gemfile.lock
file from your repository and add an entry in the .gitignore
file to avoid it from being checked in again.
Questions?
This entire guide is open-source. Go ahead and edit it if you have a fix or ask for help if you run into trouble and need some help.
© 2008–2018 Tom Preston-Werner and Jekyll contributors
Licensed under the MIT license.
https://jekyllrb.com/docs/continuous-integration/travis-ci/