cloud_formation.rb

# http://docs.aws.amazon.com/sdkforruby/api/frames.html

require "aws-sdk-v1"
require "aws-sdk"
require "json"

# Functions
# @folder = "test"
# @folder = "sample"
@folder = "production"
def string_from_json_file(file_name)
  name = "#{@folder}/#{file_name}.json"
  if File.exists? name
    file = File.open name
    data = file.read
    file.close
    data.to_str
  else
    ""
  end
end

# Variables
image_id = "ami-3d50120d"

stack_policy_body = string_from_json_file "stack_policy"
template_json     = string_from_json_file "template"

["parameters", "mappings", "conditions", "resources", "outputs"].each do |key|
  template_json.gsub! Regexp.new("{{#{key}}}"), string_from_json_file(key)
end

[
  {
    regexp: /{{image_id}}/,
    value:  image_id
  }
].each do |hash|
  template_json.gsub! hash[:regexp], hash[:value]
end

now       = Time.now
timestamp = now.strftime("%Y%m%d%S%M%I")

credentials = Aws::Credentials.new(
  ENV["AWS_ACCESS_KEY_ID"],
  ENV["AWS_SECRET_ACCESS_KEY"]
)

region            = "us-west-2"
availability_zone = "us-west-2a"

client = Aws::CloudFormation::Client.new(
  credentials: credentials,
  region:      region
)
resource = Aws::CloudFormation::Resource.new(client: client)

puts template_json

valid = false
begin
  client.validate_template(template_body: template_json)
  valid = true
rescue Exception => e
  puts e
  valid = false
end

if valid
  stack = resource.create_stack(
    parameters: [
      
    ],
    stack_name:        "stack-#{timestamp}",
    # stack_policy_body: stack_policy_body,
    template_body:     template_json
  )
  puts resource.stacks
end