Ruby Hooks

The hook execute option can also be provided Ruby code instead of a string. Here’s how it works:

  1. When the execute option is a String: Kubes will shell out and run it as a script.
  2. When the execute option is a Ruby object: Kubes will perform the call method on the object or class.

Ruby Class

When the Ruby object is a class with an instance method call, Kubes creates a new instance of the class and runs its call method. Example:


class EnvExporter
  def call
    ENV['SECRET_FOO'] = Base64.strict_encode64("hi").strip

  execute: EnvExporter,

Kubes will do something like this:

The example sets the SECRET_FOO environment variable. It is then available from ERB in the kubes resource files. For example:


  namespace: garden
  name: demo-secret
    app: garden
apiVersion: v1
kind: Secret
  foo: <%= ENV['SECRET_FOO'] %>

Note, the example above is used to explain how Ruby can be used as the execute option. For secrets, kubes supports secrets with some helpers. See: Secrets Pattern Docs

Ruby Object

When the Ruby object, Kubes expects it to have a call method and will run it. Example:


  execute: lambda { ENV['SECRET_FOO'] = Base64.strict_encode64("hi2").strip }

Kubes will do something like this:


Process Context

The context in which the hook runs is worth highlighting. When the execute option is a String, Kubes runs the script in a new child process. This the script is an independent process, and whatever is done to its environment is segregated.

When the execute option a Ruby object, then Kubes runs the hook within the same process. It means the hook can affect the same environment. IE: Setting environment variables.