Rails 5 - config.assets.compile should be true - why?

Question

I am developing Rails 5 application and use assets pipeline. It work well in development mode, but if I try to run it in production mode, it can't load images & styles correctly. I checked and found that it is because

config.assets.compile = false

in config/environments/production.rb

Unless I set it true, it doesn't work at all. I know live compilation isn't good for production, what is solution?

Answer 1

There are two options related to serving assets within a Rails server:

Asset compilation

config.assets.compile = true

refers to asset compilation. That is, whether Rails should recompile the assets when it detects that a new version of the source assets is there. In development, you want to have it set to true, so that your styles get compiled when you edit the css files. With the next request, Rails will automatically recompile the assets. On production, you usually want to set it to false and handle asset compilation during deployment. For this, you have to run

RAILS_ENV=production bin/rails assets:precompile

Usually, if you deploy using Capistrano, it takes care of that.

Asset serving

The second option related to assets is

config.public_file_server.enabled

This describes whether it is Rails that should serve the compiled files from the public/assets directory. In development, you want that, so it's true by default. In production, you usually don't want to fire up your web server to serve the logo image or a css file, so you probably compile the assets and then host them separately (for example, on a CDN like cloudfront). If you still want them to be served in production, you can launch Rails with:

RAILS_SERVE_STATIC_FILES=true RAILS_ENV=production bin/rails server