Heroku Slug Size Reduction - .slugignore issue - ruby-on-rails

Question

I got this error again... I don't remember how I fixed the first time this time I tried using the .slugignore file to exclude things I don't need my main folder that is taking for slug size is vendor, and node modules, I used
Heroku run bash -a businessappk3400
» Warning: Heroku update available from 7.42.5 to 7.42.8.
Running bash on ⬢ businessappk3400... up, run.8800 (Standard-1X)
~ $ du -sh * | sort -hr
and got :
So I am looking into reducing the vendor and node module files I tried putting them in the .slugignore folder I created in the root folder like this:
.slugignore:
# Ignore bundler config.
/.bundle
# Ignore the default SQLite database.
/db/*.sqlite3
/db/*.sqlite3-journal
# Ignore all logfiles and tempfiles.
./log
./tmp
./storage
./public
./node_modules
./yarn-error.log
./heroku
./vendor
./vendor/bundle
./kevin
./kevin.pug
./package-lock.json
./config/environments/database.yml
./package-lock.json
./vendor/database.yml
./public/packs
./public/packs-test
./yarn-error.log
./yarn-debug.log
.yarn-integrity
but I still pass the 500mb limit on slug... anyone has resolved this issue?
error:
WARNING in entrypoint size limit: The following entrypoint(s) combined asset size exceeds the recommended limit (244 KiB). This can impact web performance.
Entrypoints:
builder (1.02 MiB)
js/builder-ba7328e435e703a663b7.js
Asset precompilation completed (268.67s)
Cleaning assets
Running: rake assets:clean
-----> Detecting rails configuration
###### WARNING:
You have not declared a Ruby version in your Gemfile.
To declare a Ruby version add this line to your Gemfile:
```
ruby "2.6.6"
```
For more information see:
https://devcenter.heroku.com/articles/ruby-versions
###### WARNING:
Removing `Gemfile.lock` because it was generated on Windows.
Bundler will do a full resolve so native gems are handled properly.
This may result in unexpected gem versions being used in your app.
In rare occasions Bundler may not be able to resolve your dependencies at all.
https://devcenter.heroku.com/articles/bundler-windows-gemfile
###### WARNING:
Detecting rails configuration failed
set HEROKU_DEBUG_RAILS_RUNNER=1 to debug
-----> Discovering process types
Procfile declares types -> web, worker
Default types for buildpack -> console, rake
-----> Compressing...
! Compiled slug size: 565.7M is too large (max is 500M).
! See: http://devcenter.heroku.com/articles/slug-size
! Push failed
The complete error can be found here: https://codepen.io/apesyntax/pen/oNLvWdB

Answer 1

To reduce the Heroku slug size of my app (Rails 6.0.4.4, Ruby 3.1), I did the following:
Restrict 'wkhtmltopdf-binary' gem to development/test environments & add 'wkhtmltopdf-heroku' gem to production environment in my Gemfile (ref: https://www.eyupatis.com/how-to-decrease-heroku-slug-size-wkhtmltopdf-edition/):
gem 'wkhtmltopdf-binary', group: [:development, :test]
gem 'wkhtmltopdf-heroku', group: :production
Add 'heroku-buildpack-post-build-clean' AFTER the nodejs and ruby buildpacks in Heroku (ref: https://www.eyupatis.com/how-to-decrease-heroku-slug-size-post-build-clean-buildpack-edition/):
heroku buildpacks:add --index 3 https://github.com/Lostmyname/heroku-buildpack-post-build-clean
After this step, running heroku buildpacks listed my buildpacks as:
heroku/nodejs
heroku/ruby
https://github.com/Lostmyname/heroku-buildpack-post-build-clean
Create .slug-post-clean file in the root directory & add the /node_modules path as the only line in the file (ref: https://johntornow.com/tech/2020/04/heroku-slug-size):
/node_modules
(NOTE: the node_modules path for your project may be different than what's shown here)
Compiled slug size:
Before: 525Mb
After: 258Mb 🤯 (a 50% reduction!!!!)

Answer 2

The resolution for this app was:
Use npm to uninstall modules we did not need or use...
The only way we could make the slug change when deploying the app.
we tried before and didn't work:
-Restoring Heroku cache
-Regenerating the slug in a Linux system
-deleting the vendor folder
-deleting files and no Heroku reduction at all
-contacting support
app details:
Ruby 2.3.3
with web pack + webpacker