actions-ruby.md

Creating and invoking Ruby actions

The process of creating Ruby actions is similar to that of other actions. The following sections guide you through creating and invoking a single Ruby action, and demonstrate how to bundle multiple Ruby files and third party dependencies.

Ruby actions are executed using Ruby 2.5. To use this runtime, specify the wsk CLI parameter --kind ruby:2.5 when creating or updating an action. This is the default when creating an action with file that has a .rb extension.

An action is simply a top-level Ruby method. For example, create a file called hello.rb with the following source code:

def main(args)
  name = args["name"] || "stranger"
  greeting = "Hello #{name}!"
  puts greeting
  { "greeting" => greeting }
end

An action supports not only a JSON object but also a JSON array as a return value.

It would be a simple example that uses an array as a return value:

def main(args)
  nums = Array["a","b"]
  nums
end

You can also create a sequence action with actions accepting an array param and returning an array result.

You can easily figure out the parameters with the following example:

def main(args)
  args
end

Ruby actions always consume a Hash and return a Hash. The entry method for the action is main by default but may be specified explicitly when creating the action with the wsk CLI using --main, as with any other action type.

You can create an OpenWhisk action called hello_ruby from this function as follows:

wsk action create hello_ruby hello.rb

The CLI automatically infers the type of the action from the source file extension. For .rb source files, the action runs using a Ruby 2.5 runtime.

Action invocation is the same for Ruby actions as it is for any other action.

wsk action invoke --result hello_ruby --param name World

{
  "greeting": "Hello World!"
}

Find out more about parameters in the Working with parameters section.

Packaging Ruby actions in zip files

You can package a Ruby action along with other files and dependent packages in a zip file. The filename of the source file containing the entry point (e.g., main) must be main.rb. For example, to create an action that includes a second file called helper.rb, first create an archive containing your source files:

zip -r hello_ruby.zip main.rb helper.rb

and then create the action:

wsk action create hello_ruby --kind ruby:2.5 hello_ruby.zip

A few Ruby gems such as mechanize and jwt are available in addition to the default and bundled gems. You can use arbitrary gems so long as you use zipped actions to package all the dependencies.