Installing Ruby / GSL in Heroku Application

Question

Context:

• I have an application that makes heavy use of the GSL library and its Ruby bindings.
• I'd like to deploy the app to Heroku. I'm very new to programming in general, much less deployment, and Heroku is very simple to use, especially for Rails apps.
• I have GSL installed on my laptop. I am using the 'gsl' gem.

The Problem:

• The gem requires that the GSL library already be installed.
• GSL is not already installed in the Heroku environment.

• So, unsurprisingly, I get this error from Heroku after I git push heroku master

  -----> Heroku receiving push
  -----> Removing .DS_Store files
  -----> Ruby/Rails app detected
  -----> Installing dependencies using Bundler version 1.2.0.rc
         Running: bundle install --without development:test --path vendor/bundle --binstubs bin/ --deployment
  
  ...
  Installing gsl (1.14.7) with native extensions
  Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
  /usr/local/bin/ruby extconf.rb
  checking gsl version... *** extconf.rb failed ***
  Could not create Makefile due to some reason, probably lack of
  necessary libraries and/or headers.  Check the mkmf.log file for more
  details.  You may need configuration options.
  Provided configuration options:
  --with-opt-dir
  --without-opt-dir
  --with-opt-include
  --without-opt-include=${opt-dir}/include
  --with-opt-lib
  --without-opt-lib=${opt-dir}/lib
  --with-make-prog
  --without-make-prog
  --srcdir=.
  --curdir
  --ruby=/usr/local/bin/ruby
  extconf.rb:237:in `rescue in <main>': Check GSL>=0.9.4 is installed, and the command "gsl-config" is in search path. (RuntimeError)
  from extconf.rb:138:in `<main>'
  

The (Probable) Solution:

• It seems that working with Heroku's buildpacks is the likely route. This (packing binary buildpack dependencies) seems promising.
• I just don't understand what is going on in the tutorial, or how to use vulcan.

What I am hoping for:

• An easy-to-follow explanation of how to make the GSL library available to my application on Heroku.

Thank you so much!!

Answer 1

Hey Tom (what's the likelihood of two people named Tom needing to use ruby-gsl on heroku?) I've yet to test it out (I really don't exactly know what I'm doing and I don't really have an app ready yet to test it with) but maybe this'll work:

heroku-buildpack-gsl-ruby

if not, well, we'll keep at it ;)

It's gsl 1.15 which is currently the latest.

Though in the future something like: package_nodejs instead for gsl might be nice (see hacking section of the readme). I'll probably add that soon (copy/paste, shudder, so not DRY).