capistrano (v3) deploys the same code on all roles - capistrano

Question

If I understand correctly the standard git deploy implementation with capistrano v3 deploys the same repository on all roles. I have a more difficult app that has several types of servers and each type has its own code base with its own repository. My database server for example does not need to deploy any code.
How do I tackle such a problem in capistrano v3?
Should I write my own deployment tasks for each of the roles?

Answer 1

How do I tackle such a problem in capistrano v3?
All servers get the code, as in certain environments the code is needed to perform some actions. For example in a typical setup the web server needs your static assets, the app server needs your code to serve the app, and the db server needs your code to run migrations.
If that's not true in your environment and you don't want the code on the servers in some roles, you could easily send a pull request to add the no_release feature back from Cap2 in to Cap3.
You can of course take the .rake files out of the Gem, and load those in your Capfile, which is a perfectly valid way to use the tool, and modify them for your own needs.
The general approach is that if you don't need code on your DB server, for example, why is it listed in your deployment file?

Answer 2

I can confirm you can use no_release: true to disable a server from deploying the repository code.
I needed to do this so I could specifically run a restart task for a different server.
Be sure to give your server a role so that you can target it. There is a handy function called release_roles() you can use to target servers that have your repository code.
Then you can separate any tasks (like my restart) to be independent from the deploy procedure.
For Example:
server '10.10.10.10', port: 22, user: 'deploy', roles: %w{web app db assets}
server '10.10.10.20', port: 22, user: 'deploy', roles: %w{frontend}, no_release: true
namespace :nginx do
desc 'Reloading PHP will clear OpCache. Remove Nginx Cache files to force regeneration.'
task :reload do
on roles(:frontend) do
execute "sudo /usr/sbin/service php7.1-fpm reload"
execute "sudo /usr/bin/find /var/run/nginx-cache -type f -delete"
end
end
end
after 'deploy:finished', 'nginx:reload'
after 'deploy:rollback', 'nginx:reload'
# Example of a task for release_roles() only
desc 'Update composer'
task :update do
on release_roles(:all) do
execute "cd #{release_path} && composer update"
end
end
before 'deploy:publishing', 'composer:update'
I can think of many scenarios where this would come in handy.
FYI, this link has more useful examples:
https://capistranorb.com/documentation/advanced-features/property-filtering/