However, some gems depend on binaries (eg Paperclip depends on ImageMagick, PDFKit depends on wkhtmltopdf) that may or may not be installed on the system being deployed to.

I've been bitten by this twice recently and need to figure out the best way to prevent it from happening again.

Is there a good way to ensure these external binaries and libraries are installed? Does bundler have any support for it? Should I just modify my capistrano deploy script? Should I include the binaries in my repository and make sure the gems look for them in the right place?

I can think of a few ways to approach this problem but want to know what you think works best, and why.

I currently have a bounty question on Stackoverflow[1] but haven't received much of a response and thought I'd ask here as well. I guess it's more of a sysadmin question than a programming question, but an ideal solution would be part of my repositories and deploy process.

[1] http://stackoverflow.com/questions/6147129/how-should-i-manage-binary-dependencies-for-my-gems-in-production