erubis | Erubis is an fast and extensible eRuby implementation

Looks like you're running into compatibility issues trying to use the latest version of the activerecord-import gem at the time of writing (released in October 2020) with activerecord 3.2.22.5 (released in September 2016). You do mention it's a rails 3.2.15 app but you're not using activerecord 3.2.15 which is confusing.

Try using activerecord-import 0.4.1 (released in July 2013) and activerecord 3.2.15 which should be compatible with rails 3.2.15.

Thanks to jonrsharpe comment, I reoriented my searches and found this blog post on heroku engineering blog. Eventually, as stated by jonrsharpe:

The Nginx buildpack won't have Ruby in at all - you need to do any building in the Ruby buildpack context, so all the static buildpack needs to do is serve the results.

Therefore, to launch my middleman build command, I needed to hook somewhere in the ruby buildpack thing. And in the "jekyll on heroku" link, everything is explained: one should override the assets:precompile rake task.

1. Add gem "rake" to my Gemfile (and bundle, of course)
2. Create a Rakefile with the assets:precompile task :

Try updating your Gemfile to use json@1.8.2 instead of 1.8.1 - according to this thread Ruby 2.2.x is incompatible with json 1.8.1.

1.8.2 should be functionally similar and not affect any of your other dependencies.

You can also run bundle update json to let bundler try to fix it for you - but that may put you at a much later version than 1.8.2, I'm not sure.

No harm in trying a couple things and reverting your changes.

As you just removed the files instead of using apt-get or dpkg to uninstall the package, the package management is not aware of your manual removal, and so apt-get and dpkg still think the newest version is already installed, and so do nothing.

apt-get --reinstall install vagrant

should solve this.

Thanks to @Les Nightingill, I found the issue.

It was not directly linked to assets generation, but the probleme was indicated at the first error line in the logs :

I think I see what's going on. In your Dockerfile, change your DB_URL from: mysql:// to mysql2://

You are loading the mysql2 gem, but indicating to ActiveRecord that you want to use a connection via the mysql gem.

This is probably and error with the stylesheet_link_tag and stylesheet_pack_tag, check out your layout files probably you are including sass files and you are using stylesheet_link_tag, this is breaking your code given that as I understand you can just link plane css files. so if you are including sass files use the stylesheet_pack_tag

It's common error, gem is trying to compile on your server, and appears that your centos is missing mysql/mariadb development headers.

To fix this, simply run this as a root: