How I make deployments convenient

For some of my modules, I also run a demo website that shows off the features and use of each module. Case in point, HTTP::Request::FromCurl has an online converter on my website.

I like to use git as my deployment tool, becuase it conveniently abstracts the packaging and transport. Basically, a deployment becomes

git push demo

The main magic is just a small program (called a "git hook") on the remote machine that gets run by git whenever I push a new version to the remote repository. This git hook is a shell script which looks like the following:

#!/bin/sh
git --work-tree=/home/corion/github-rss --git-dir=/home/corion/GitHub-RSS.git checkout -f
PERL5LIB= /home/corion/perl-5.24/bin/cpanm --installdeps /home/corion/github-rss -l /home/corion/github-rss/extlib

# Migrate the database
# We use the system Perl here...
PERL5LIB= /home/corion/bin/update-db.pl --from dbi:SQLite:dbname=/home/corion/corion.net/github-rss/issues.sqlite --to HEAD --file sql/create.sql --git-dir /home/corion/GitHub-RSS.git/

The second line checks out the git repository from Github-RSS.git into the directory /home/corion/github-rss.

The third line updates all prerequisites from CPAN into a local directory below /home/corion/github-rss. This means that for every demo site, I have a complete library installation. The upside of that is that I can migrate each demo site to a new Perl version individually.

The fourth statement is for database migrations and . automatically migrates the database to the new version. Hopefully all my schema changes can be done lossless or I have an intermediate change that introduces the new schema without destroying the old schema.

The code for update-db.pl and the post-receive hook live in the deployment/ directory of my distribution template.