Glyphicon not showing in Heroku(it was normal before)

Question

I have a rails 4 application and everything was working fine, until now, instead of the bootstrap glyphicon it appears only a square! I don't know why, I didn't change anything... I want a solution DIFFERENT FROM `changing config.assets.precompile = true, once it is not a good practice and your application will run slowly if you do it.(See config.assets.compile=true in Rails production, why not?). Thanks!

Answer 1

Because you didn't compile your assets locally, heroku tried to compile them but it failed. That is called slug compilation.

The solution is to compile your files locally, and commit the public/assets folder. To do that you need to run:

RAILS_ENV=production bundle exec rake assets:precompile

Why heroku failed compiling your assets? It could be because it detected a manifest file into your assets folder, and it assumed that you compiled your assets manually.