Capistrano 3: way to handle different deploy flows - capistrano3

Question

I am new to Capistrano, but I have succeded on getting it working for a custom deploy. I have to deploy Moodle to a cluster with an auto-scaling group in AWS and one or more static servers.
It works great! I have managed to alter the flow with custom tasks to put my site on maintenance and clear cache without problems:
namespace :moodle do
desc 'Save config.php from current release directory' task :'save-config'
on roles(:web) do
execute :sudo, :cp, shared_path.join('config.php'), release_path
execute :sudo, :chown, 'www-data-aulatp:www-data', release_path.join('config.php')
end
end
desc 'Copy config.php to release directory' task :'restore-config' do
on roles(:web) do
execute :sudo, :cp, shared_path.join('config.php'), release_path
execute :sudo, :chown, 'www-data-aulatp:www-data', release_path.join('config.php')
end
end
desc 'Enable maintenance mode on Moodle site' task :'enable-maintenance' do
on roles(:admin) do
execute :sudo, '-u', 'www-data-aulatp', '/usr/bin/php7.0', current_path.join('admin', 'cli', 'maintenance.php'), '--enable'
end
end
desc 'Disable maintenance mode on Moodle site' task :'disable-maintenance' do
on roles(:admin) do
execute :sudo, '-u', 'www-data-aulatp', '/usr/bin/php7.0', current_path.join('admin', 'cli', 'maintenance.php'), '--disable'
end
end
desc 'Purge all internal Moodle caches' task :'purge-caches' do
on roles(:admin) do
execute :sudo, '-u', 'www-data-aulatp', '/usr/bin/php7.0', current_path.join('admin', 'cli', 'purge_caches.php')
end
end
end
before 'deploy:starting', 'moodle:save-config'
before 'deploy:updated', 'moodle:enable-maintenance'
after 'deploy:updated', 'moodle:restore-config'
after 'deploy:finished', 'moodle:enable-maintenance'
after 'deploy:finished', 'moodle:disable-maintenance'
after 'deploy:finished', 'moodle:purge-caches'
The problem is, sometimes I will need to make quick deploys, a small patch that does not need enabling and disabling maintenance mode or purging caches.
Would it be posible with capistrano?
As a posible alternative, I have been looking also to capistrano-patch, a way to deploy a simple patch to every server without creating a full deploy process. It looks like it has not ben updated for some years and I suppose it will not work with capistrano 3. Any similar ideas to do HOTFIX with Capistrano 3?

Answer 1

You could use environment variables to state that something needs to be bypassed. E.g., you could run your deploy with NO_CACHE_PURGE=true cap production deploy and then wrap the relevant code with something like:
desc 'Purge all internal Moodle caches'
task :'purge-caches' do
if ENV['NO_CACHE_PURGE'].nil?
on roles(:admin) do
execute :sudo, '-u', 'www-data-aulatp', '/usr/bin/php7.0', current_path.join('admin', 'cli', 'purge_caches.php')
end
else
puts 'Skipping purge-caches due to env variable'
end
end
If you know Ruby well, and you want to automate this, you could probably write a method which would simplify some of this (the following code is untested):
def disableable_task(*args)
if ENV[args[:env_name]].nil?
task(args)
else
puts "Skipping #{args[0]} due to #{args[:env_name]} environment variable being set"
end
desc 'Purge all internal Moodle caches'
disableable_task :'purge-caches', env_name: 'NO_CACHE_PURGE' do
on roles(:admin) do
execute :sudo, '-u', 'www-data-aulatp', '/usr/bin/php7.0', current_path.join('admin', 'cli', 'purge_caches.php')
end
end