Ruby on Rails

I've upgraded to rails 5.2 and am implementing ActiveStorage.  ActiveStorage uses mutool for PDF processing.  I have successfully installed mutool locally using homebrew.

    mutool is a bit confusing.  

    

    rails docs claim to require "mutool", 

    homebrew installs "mupdf-tools", 

    and heroku wants "mupdf".

I have successfully installed apt and mupdf on heroku following these steps:

    - add a new Aptfile to the root of my application with only "mupdf" listed

    - commit and push the Aptfile

    - THEN run heroku buildpacks:add --index 1 https://github.com/heroku/heroku-buildpack-apt

    - push again so heroku will finish installing apt and mupdf

   

mupdf builds successful during the push

    

    heroku buildpacks now returns    

    1. https://github.com/heroku/heroku-buildpack-apt

    2. heroku/ruby

If I refresh a page calling for a variant on a PDF, the image fails to process and the job kicks back the following error:

      Errno::ENOENT: No such file or directory - mutool

It seems mutool and mupdf are synonomous...so, I tried swapping out mutool for mupdf in my Aptfile...that failed to build from "...not found'.

Anyone know what action I need to take?

PS:  This is part of implementing rails 5.2 using ActiveStorage.

# UPDATE

I added mupdf-tools to Aptfile and that seems to fix the "no such file or directory" error.  I don't know for sure because a new errors surfaces

    MiniMagick::Invalid: `identify /tmp/mini_magick20180105-4-pvub9r` failed with error: identify.im6: no decode delegate for this image format `/tmp/mini_magick20180105-4-pvub9r' @ error/constitute.c/ReadImage/544.

    MiniMagick::Error: `identify -format %m %w %h %b /tmp/ActiveStorage20180105-4-1f46tem[0]` failed with error: identify.im6: no decode delegate for this image format `/tmp/ActiveStorage20180105-4-1f46tem' @ error/constitute.c/ReadImage/544.