Caldecott is a ruby gem required for e. g. tunneling to AppFog services. This short writeup explains how to get it running on Windows.
I wrote this because I received the following error trying to establish a tunnel to a MySQL instance on AppFog:
To use `af tunnel', you must first install Caldecott:
gem install caldecott
Note that you'll need a C compiler. If you're on OS X, Xcode
will provide one. If you're on Windows, try DevKit.
This manual step will be removed in the future.
Error: Caldecott is not installed.
Run the DevKit executable (it is just a self-extracting 7Z archive and can be unpacked with other tools, if necessary) and extract it somewhere. Be sure to specify a new or empty directory as the destination.
Rename the directory extracted in the previous step to devkit and move it to your Ruby’s installation folder, e. g. C:\Ruby193.
Open a command prompt as an administrator (e. g. by pressing the Start button, typing cmd, right-clicking the link to the command prompt and choosing “Run as Administrator”).
Change to the devkit folder by typing e. g. cd C:\Ruby194\devkit (depends on your Ruby installation folder of course).
Run the following command: ruby dk.rb init
Run the following command: ruby dk.rb install
Finally, to install Caldecott, run the following command: