Clear Rails cache on deployment

When you use Rails view caching and change the html the caching does not know about it and you need to invalidate the cache manually. Here is how to do it before every deployment.

As described in the previous post you can run Rails.cache.clear in the Rails console to clear the cache. Unfortunately there is no way (yet) to do it from the command line. We can add a rake task that will do this for us.

Add a file called cache.rake to your lib/tasks/ folder with the following contents:

namespace :cache do
  desc "Clearing Rails cache"
  task :clear do
    Rails.cache.clear
  end
end

Then we can execute ./bin/rake cache:clear and clear the Rails cache from the command line.

Now we can execute this on every deploy on Heroku. Modify the Procfile to migrate the database and clear the cache on every deploy.

release: rake db:migrate cache:clear
web: bundle exec puma -C config/puma.rb