It seems like you are using docker-compose with a Ruby on Rails application and the gem:foreman process manager. When you stop the Docker container, the file is not being released.

This issue is likely related to how the process manager (Foreman) handles the termination of the Ruby on Rails application inside the Docker container. Foreman may not be able to clean up the file properly when the container is stopped abruptly.

To ensure the file is released properly and avoid potential conflicts or issues, you can take the following steps:

  1. Use Docker Stop Signal: Ensure that you are using the correct Docker stop signal for your Ruby on Rails application. The stop signal instructs Docker how to terminate the application gracefully when you stop the container.

    In your Dockerfile or Docker Compose file, set the STOPSIGNAL instruction to the appropriate value for Ruby on Rails applications, which is usually SIGTERM.

    Example in Dockerfile:


    Example in Docker Compose:

    version: '3' services: web: build: . stop_signal: SIGTERM
  2. Handle Signals in Ruby on Rails: Ensure that your Ruby on Rails application handles the SIGTERM signal gracefully. Rails provides a default handler for SIGTERM, which is to shut down the server gracefully and release the file. However, if you have custom signal handling, ensure it correctly releases resources when the process is terminated.

  3. Use forego or overmind Instead of Foreman: Consider using an alternative process manager like forego or overmind instead of Foreman. Both forego and overmind are more Docker-friendly and may handle process termination more reliably.

  4. Check File Permissions: Ensure that the directory where the file is stored has the appropriate file permissions so that the process inside the container can create, update, and delete the file.

  5. Use Puma Web Server: If you are using the default WEBrick web server, consider switching to Puma, which is recommended for production use and may handle process termination more gracefully.

By following these steps and ensuring proper signal handling and process management, you can avoid issues with the file and ensure your Ruby on Rails application runs smoothly inside the Docker container.

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