Prerequisites
Gem¶ ↑
A ruby gem to make it easy to test that a set of prerequisite conditions are in place.
This can be useful when using ruby as 'glue' code for sysadmin or other tasks.
Installation¶ ↑
gem install prerequisites
Or add to your Gemfile
:
gem "prerequisites"
Usage¶ ↑
This example checks that:
-
Environment variables “FOO” and “BAR” are set
-
Environment variable “BAZ” is set to the value “whatever”
-
Executables “grep”, “git”, and “kubectl” are in your $PATH
-
The shell commands execute successfully
NB: You should ensure that any commands you list in the
shell_commands
section have no side-effects. These are supposed to be pre-flight checks.
config = { environment_variables: [ "FOO", "BAR", { "BAZ" => "whatever" } ], executables_in_path: [ "grep", "git", "kubectl" ], shell_commands: [ "echo whatever | grep what", "kubectl config current-context | grep myk8scluster" ] } Prerequisites.new(config).check
If any of these conditions are not met, the code will raise an error of class:
…depending on the problem.