2018 / 01 / 28
How to set up automatic Hugo website generation and deployment with Git

Just because we can

hugo
ubuntu
debian
git
gitolite

Let’s say that you have tried Hugo, you liked it, and made a website with it.
Now you are ready to deploy that website for the whole world to see.

Wouldn’t it be great if you could just do:

git add .
git commit -m "Updated blog content"
git push

And be done with it?

Well, if that sounds like your kind of thing; something you’d like to have…
Then read on my friend!


Inventory

What do you need for this tutorial?

  • A public server somewhere. If you don’t have one, you can get a VPS (Virtual Private Server) from Linode, DigitalOcean or similar providers.
  • An account with access to sudo.
  • You have git available, from this guide.
  • You use Gitolite to manage your repositories, from this guide.
  • A configured webserver —I recommend looking into NGINX, since it’s super easy to setup in Ubuntu.

Let’s assume:

  1. A local ~/.ssh/config file with this content:

     Host git-server
       # This is the IP for your VPS
       HostName 111.111.111.111
       Port 22
       # This is the remote user
       User yolo
    
     Host web-server
       # This is the IP for your other VPS
       HostName 222.222.222.222
       Port 22
       # This is the remote user
       User webcustomer
  2. You have your Hugo project versioned with git and you can push code to the remote repository.

  3. The repository’s name is yolo-web, so you can clone it like this:

     git clone git@git-server:yolo-web

Install dependencies

First, let’s login on the remote machine; the one you want to setup automatic deployment on.

Open a terminal and SSH into it:

ssh git-server

We need the hugo command available, for that the easiest way is to use snapd:

sudo apt install snapd
sudo snap install hugo

Login as the git user and verify hugo is working:

sudo su git -l
hugo version

You should see something like:

Hugo Static Site Generator v0.34 linux/amd64 BuildDate:

Create and configure the post-receive hook script

This is the important part.

This script will be in charge of doing something after the repository receives a git push.
In our case, we want the script to git checkout a copy of the current master branch in a directory of our choosing and then call hugo on it to generate the HTML files for the web server.

Let’s create the post-receive file:

touch ~/repositories/yolo-web.git/hooks/post-receive
chmod 700 ~/repositories/yolo-web.git/hooks/post-receive

And put this content inside:

#!/bin/bash

export GIT_WORK_TREE=/home/git/yolo-web-compiled

echo `pwd`
echo "Generating site with Hugo for yolo-web"

mkdir -p $GIT_WORK_TREE
chmod 755 $GIT_WORK_TREE

git checkout -f master

rm -rf $GIT_WORK_TREE/public
cd $GIT_WORK_TREE && /snap/bin/hugo

find $GIT_WORK_TREE/public -type f -print | xargs -d '\n' chmod 644
find $GIT_WORK_TREE/public -type d -print | xargs -d '\n' chmod 755

echo "All done! 0 problems"

You now have a process in place that will leave the latest HTML files generated by Hugo in /home/git/yolo-web-compiled.

Go ahead, try it out, make some local changes, git commit and git push, then SSH in and see what’s inside /home/git/yolo-web-compiled.

The web server situation

Same server for compiling and web serving

If your web server is in the same machine as your repos, then you can simply point with a symbolic link to the /home/git/yolo-web-compiled/public directory and call it a day!

Else…

Compiling in one server, web serving in another

What if you have different machines for hosting your Git repositories and hosting your web pages?

How would that work? Glad you asked…


What follows is an opinionated soluion to this problem.

  1. Generate an SSH key pair for the git@git-server user with an empty passphrase:

     ssh git-server
     sudo su git -l
     sshkey-gen -t rsa -b 4096 -C "git@git-server"
  2. Try to access the web server through SSH —it’ll fail, but we need this so its signature gets registered into the ~/.ssh/know_hosts file.

     ssh webcustomer@222.222.222.222

    You should answer yes —don’t just type y— when it asks:

     Are you sure you want to continue connecting (yes/no)?
  3. exit the git user shell, you are now in your yolo shell.

  4. Copy the public key from git to your home:

     sudo cp /home/git/.ssh/id_rsa.pub ~/git.pub
  5. sudo chown $USER:$USER git.pub

  6. exit the remote session, you are now in your local machine.

  7. Copy the git.pub file to your local machine:

     mkdir ~/tmp
     scp git-server:git.pub ~/tmp/
  8. Upload the key to the server where the page is going to be hosted:

     scp ~/tmp/git.pub web-server:
  9. Login to the web server machine:

     ssh web-server
  10. Copy the contents of ~/git.pub at the end of ~/.ssh/authorized_keys.

    That’s it, SSH into git-server, then sudo su git -l and test that ssh webcustomer@222.222.222.222 works.

    If the last SSH login work, you can now scp or rsync content from the repository machine to the web server machine!

  11. Modify the ~/repositories/yolo-web.git/hooks/post-receive file and include a call to rsync or scp to transfer files from git-server to web-server —I prefer to use rsync:

#!/bin/bash

export GIT_WORK_TREE=/home/git/yolo-web-compiled

echo `pwd`
echo "Generating site with Hugo for yolo-web"

mkdir -p $GIT_WORK_TREE
chmod 755 $GIT_WORK_TREE

git checkout -f master

rm -rf $GIT_WORK_TREE/public
cd $GIT_WORK_TREE && /snap/bin/hugo

find $GIT_WORK_TREE/public -type f -print | xargs -d '\n' chmod 644
find $GIT_WORK_TREE/public -type d -print | xargs -d '\n' chmod 755

rsync -avzP $GIT_WORK_TREE/public/ \
webcustomer@222.222.222.222:/var/www/yolo-web/html

echo "All done! 0 problems"

NOTE: You’ll need to tweak the last param for the rsync command above to match your website’s files path.