Heroku page displays an error while "heroku logs" do not

Question

My Heroku-hosted Rails site is showing that an error has occurred, but when I run heroku logs no error is listed. It does show the action that is causing the error but it lists it the same way it does every other successful action.

This is the first time heroku logs hasn't displayed the errors for this site. Has anyone had this problem before and found a solution?

Answer 1

For Rails 4, add rails_12factor gem to your Gemfile in order to get detailed logs of your application. Additionally it fixes some other weired problems about Heroku too.

Add this to your Gemfile:

gem 'rails_12factor'

Answer 2

I've noticed this too. Heroku has several logging levels. You should try this:

heroku config:add LOG_LEVEL=DEBUG
heroku addons:upgrade logging:expanded

Then go to your app and get ready to hit the page with an error. But before you do do this:

heroku logs --tail

And you should be able to see the errors in you console.