Rails app inside docker not detecting file changes

Question

I'm running a Rails application inside a docker container. None of my file changes are being detected and auto-reloaded by Rails.

My docker application's main directory is mounted as a docker volume that maps to my host directory. In my docker-compose.yml:

services:
  my_app:
    # ...
    volumes:
      - .:/app

My rails app is configured to use ActiveSupport::FileUpdateChecker:

# config/environment/development.rb
config.cache_classes = false
config.reload_classes_only_on_change = true
config.file_watcher = ActiveSupport::FileUpdateChecker

What I've Tried

Inside the Rails framework:

• Here is where the logic is implemented to check if any files are updated. Below that you can also see where it loads the file_watcher
• Here is the implementation of the FileUpdateChecker, specifically where it checks the maximum updated timestamp (mtime) for each watched path/file

I added print/logging statements inside the Rails gem to see if it was getting called.

When I update a file inside my application, I expect it to be detected by the file watcher but nothing is happening, and nothing gets printed.

Is this expected behavior on docker ? Or is there a way to hot reload while running inside a docker container?