On install : the asset "active_admin.css" is not present in the asset pipeline.

[Andrew-Max]

Did you find a bug?

On a fresh install with rails 6 and rails-sass no assets get installed and going to '/admin' results in an error: The asset "active_admin.css" is not present in the asset pipeline.

Expected behavior

Should go to a login screen

Actual behavior

An error is thrown

How to reproduce

Fresh install according to the guide's 'Installation' section

[Andrew-Max]

It looks like this is solved by rails generate active_admin:assets but it is worth noting that the documentation does not instruct the user to ever run this command on a fresh install.

[guilpejon]

In my case that command did not solved the error because I already had the files app/assets/javascripts/active_admin.js and app/assets/stylesheets/active_admin.scss.
Anyone else having this problem? I'm thinking it has something to do with the fact that Rails 6 uses webpack by default, but the assets are generated on app/assets.

[deivid-rodriguez]

I think you're supposed to use sassc-rails instead of sass-rails, maybe that's the issue?

[deivid-rodriguez]

Actually scratch that since I just realized that sass-rails is just a wrapper around sassc-rails. rails generate active_admin:install should run rails generate active_admin:assets so I don't know what's going on here. I also tried to reproduce this, but everything worked correctly.

Could you share some steps to reproduce this?

[Arugin]

Upgraded from rails 4 to rails 6, In the development envirobment everything works ok. In the production has the same error.

[deivid-rodriguez]

Could you share some steps to reproduce this?

[mrtomhoward]

@Arugin and others still experiencing this problem.

I had this issue today with an app that was initially built in Rails 5 and that I recently updated to Rails 6.

What fixed it for me was running rails app:update (and manually reviewing all the environment and initializer files as some are updated or overwritten by the update procedure).

I hadn't done that before now; I'd only updated the Rails Gem.

After doing that, Active Admin loads without any problems.

With my install, the newly updated config/application.rb had this line commented out:
#require "sprockets/railtie"

...which I believe is the Rails 6 way of disabling the asset pipeline (and which suits me fine as this app is API-only apart from ActiveAdmin).

But I tried loading the app wth require "sprockets/railtie uncommented, and it works fine that way too.

[oyenmwen]

This problem can occur with Rails 6 apps as they use Webpacker as the default asset generator. You need to explicitly configure activeadmin to use webpacker.

at active_admin installation:
run rails g active_admin:install --use_webpacker

If already installed:

add config.use_webpacker = true at config/initializers/active_admin.rb
and then run rails g active_admin:webpacker

Source: https://activeadmin.info/0-installation.html#setting-up-active-admin

[tanoargie]

This problem can occur with Rails 6 apps as they use Webpacker as the default asset generator. You need to explicitly configure activeadmin to use webpacker.

at active_admin installation:
run rails g active_admin:install --use_webpacker

If already installed:

add config.use_webpacker = true at config/initializers/active_admin.rb
and then run rails g active_admin:webpacker

Source: https://activeadmin.info/0-installation.html#setting-up-active-admin

Thanks! This fixed the issue for me!

[mmell]

This happened to me on a fresh Rails 6 site. It only manifested in the production deployment.

[Zidail]

Seems like I'm having the same issue with a fresh install of Active Admin.
It works in development but doesn't in production.
Doesn't seem like webpacker picked up the scss file.

Followed the instructions in: https://activeadmin.info/0-installation.html#setting-up-active-admin

EDIT: Solved. Nothing to do with the setup. Just needed to rebuild the webpacker assets and it was good to go. Silly me. @mmell you might want to give this a try.

[mmell]

Setting RAILS_SERVE_STATIC_FILES=1 in the production environment solved it for me.

[ahmadoji01]

In case someone still having the same issue after trying all the solutions above. I opened the config/webpacker.yml and change this line:

default: &default
  ...
  extract_css: true
  ...

Somehow, my app wants to have the webpacker to also emit the css for the active_admin.css to be identified. Hopefully it will help someone here

[thisismydesign]

Happens when there's no app/assets folder, e.g. for api-only apps. Fix by creating the folder or rails generate active_admin:assets