GCE 用の ansible dynamic inventory 手抜き版

gce.rb

require 'json'

class GCE

  def initialize(project_id, env)
    @project_id = project_id
    @env = env
  end

  def instance_list
    @instances ||= JSON.parse(`gcloud compute instances list --format json --project #{@project_id}`)
  end

  def parse
    target_instances = instance_list.select{|i| metadata(i, "environment") == @env }
    result = target_instances.map{|i| [role(i), name(i), zone(i)] }
    result.each_with_object({}) do |(role, name, zone), result|
      result[role] ||= { "hosts" => [],   "vars" => { "stage" => @env } }
      result[role]["hosts"] << "#{name}.#{zone}.#{@project_id}"
    end
  end

  def result
    parse.to_json
  end

  private
  def metadata(instance, key)
    return unless instance["metadata"]["items"]
    (instance["metadata"]["items"].find{|meta| meta["key"] == key } || {})["value"]
  end

  def role(instance)
    metadata(instance, "role")
  end

  def name(instance)
    instance["name"]
  end

  def zone(instance)
    instance["zone"]
  end
end

# GCE.new('your-project-id', 'production').result