Cannot install Puma gem on Ruby on Rails

Came across very same issue.

sudo apt-get install libssl-dev

fixed it for me.

I ran bundle update before bundle install and that solved the issue for me.

I'm not sure if that was the only thing that helped, as I manually updated puma before that, using these steps:

1. Checked which version of openssl Ruby is using by running ruby -v -ropenssl -e "puts OpenSSL::OPENSSL_VERSION"
2. Downloaded the right openssl version fromhttp://packages.openknapsack.org/openssl/openssl-1.0.0o-x86-windows.tar.lzma(got the link from https://github.com/hicknhack-software/rails-disco/wiki/Installing-puma-on-windows and edited it based on the output of #1).
3. Extracted openssl using http://www.7-zip.org to C:\RailsInstaller\openssl
4. gem install puma -- --with-opt-dir=C:/RailsInstaller/openssl

Figured out the solution to the puma bundle. Followed directions from https://github.com/hicknhack-software/rails-disco/wiki/Installing-puma-on-windows

First you need to download:

• DevKit compatible with your ruby version
• OpenSSL Developer Package (contains header files and binaries)

And then:

• Install DevKit, e.g. in c:\devkit
• Unpack the OpenSSL Package, e.g. in c:\openssl (use 7Zip or PeaZip)
• You need to copy the ddls from the bin directory (libeay32.dll and ssleay32.dll) to your ruby/bin directory.
• Open a windows console
• Initialize the DevKit build environment: c:\devkit\devkitvars.bat (except here, I used this in command prompt instead: ruby dk.rb init)

Now it’s possible to install the puma gem with the OpenSSL packages:

gem install puma -- --with-opt-dir=c:\openssl