Sigal push-to-deploy using git

Sigal is a simple static gallery generator. This describes how to use git to deploy it to a remote server.

Prerequisities

• You have to want (or already have to have) a sigal gallery.
• You have to want to use git to deploy it.
• You have to have a server (or access to one).
• You have to be a geek (optionally).

Local setup

Setup your Sigal gallery as usual, just sigal init and configure everything, with 2 important exceptions: don’t change photos destination nor source. Check that your gallery works by building it locally.

Prepare a suitable gitignore (at the very least ignore _build) and put your gallery under git. Please note: It is said that git is not very good when it comes to dealing with large binary files. In practice, if you are not making changes to these files and you are just adding new ones (which is the case for a photo gallery), it works just fine.

Remote setup

This is a bit more interesting part.

First the installation. You will have to install git to your server, and of course, Sigal. I presume you already have set up a web server or know how to set up one.

Prepare a bare repository for your gallery.

mkdir photos.git
cd photos.git
git init --bare

Git has a way of running custom scripts when important actions occur, such as pushes to the remote repository. These scripts are called hooks. You can read more about them here. We will setup a custom pre-receive hook. A pre-receive is the first script to run when the remote is receiving a push. It takes a list of references from stdin and can abort a push by exiting with a non-zero exit status. Here we will trigger a build of our gallery, with destination to a folder which is served by the webserver. If anything goes wrong during the build, we will reject the push.

In the repository folder you have just created you will find several directories, one of them is hooks. Create a new file there, called pre-receive and set its execute bit. Copy this, and modify it to your liking:

#!/bin/bash

set -e

TMPDIR="<Your prefered tmp dir>"
SRVDIR="<Directory which your webserver serves>"
GITDIR="<Path to the repository directory (/home/example/photos.git)>"

while read oldrev newrev ref
do
    if [[ $ref =~ .*/master$ ]]
    then
        echo 'Deploying gallery...'
        mkdir -p $TMPDIR
        git --work-tree=$TMPDIR --git-dir=$GITDIR checkout -f --quiet $newrev
        cd $TMPDIR
        export LC_ALL=en_US.UTF-8
        export LANG=en_US.UTF-8
        sigal build pictures $SRVDIR
        rm -rf * $TMPDIR
    fi
done

And that’s it. Every time you push to the master branch your gallery will be built to the $SRVDIR folder. If anything goes wrong during the build process, set -e ensures that we will exit with non-zero exit status, and therefore reject the push.