lib/kumo_keisei/stack.rb
require 'aws-sdk'
require 'kumo_config'
module KumoKeisei
class Stack
class CreateError < StandardError; end
class UpdateError < StandardError; end
class UsageError < StandardError; end
UPDATEABLE_STATUSES = [
'UPDATE_ROLLBACK_COMPLETE',
'CREATE_COMPLETE',
'UPDATE_COMPLETE'
]
RECOVERABLE_STATUSES = [
'ROLLBACK_COMPLETE',
'ROLLBACK_FAILED'
]
TERMINATED_STATUSES = [
'DELETE_COMPLETE'
]
UNRECOVERABLE_STATUSES = [
'UPDATE_ROLLBACK_FAILED'
]
attr_reader :stack_name, :env_name
def self.exists?(app_name, environment_name)
self.new(app_name, environment_name).exists?
end
def initialize(app_name, environment_name, options = { confirmation_timeout: 30, waiter_delay: 20, waiter_attempts: 90 })
@env_name = environment_name
@app_name = app_name
@stack_name = "#{app_name}-#{ environment_name }"
@confirmation_timeout = options[:confirmation_timeout]
@waiter_delay = options[:waiter_delay]
@waiter_attempts = options[:waiter_attempts]
end
def apply!(stack_config)
stack_config.merge!(env_name: @env_name)
raise UsageError.new('You must provide a :template_path in the stack config hash for an apply! operation') unless stack_config.has_key?(:template_path)
if updatable?
update!(stack_config)
else
ensure_deleted!
ConsoleJockey.write_line "Creating your new stack #{@stack_name}"
create!(stack_config)
end
end
def destroy!
return if get_stack.nil?
flash_message "Warning! You are about to delete the CloudFormation Stack #{@stack_name}, enter 'yes' to continue."
return unless ConsoleJockey.get_confirmation(@confirmation_timeout)
wait_until_ready(false)
ensure_deleted!
end
def outputs(name)
return GetStackOutput.new(get_stack).output(name)
end
def logical_resource(resource_name)
response = cloudformation.describe_stack_resource(stack_name: @stack_name, logical_resource_id: resource_name)
stack_resource = response.stack_resource_detail
stack_resource.each_pair.reduce({}) {|acc, (k, v)| acc.merge(transform_logical_resource_id(k) => v) }
end
def exists?
!get_stack.nil?
end
def config(stack_config)
raise UsageError.new('You must provide a :config_path in the stack config hash to retrieve the stack\'s config') unless stack_config.has_key?(:config_path)
environment_config(stack_config).config
end
def plain_text_secrets(stack_config)
raise UsageError.new('You must provide a :config_path in the stack config hash to retrieve the stack\'s plain_text_secrets') unless stack_config.has_key?(:config_path)
environment_config(stack_config).plain_text_secrets
end
def params_template_path(stack_config)
stack_config.has_key?(:template_path) ? File.absolute_path(File.join(File.dirname(stack_config[:template_path]), "#{File.basename(stack_config[:template_path], '.*')}.yml.erb")) : nil
end
private
def cf_params(stack_config, environment_config)
erb = params_template_erb(stack_config)
return [] unless erb
stack_params = YAML.load(erb.result(environment_config.get_binding))
KumoKeisei::ParameterBuilder.new(stack_params).params
end
def params_template_erb(stack_config)
template_path = params_template_path(stack_config)
return nil unless template_path && File.exist?(template_path)
ERB.new(File.read(template_path))
end
def transform_logical_resource_id(id)
id.to_s.split('_').map {|w| w.capitalize }.join
end
def get_stack(options={})
@stack = nil if options[:dump_cache]
@stack ||= cloudformation.describe_stacks(stack_name: @stack_name).stacks.find { |stack| stack.stack_name == @stack_name }
rescue Aws::CloudFormation::Errors::ValidationError
nil
end
def cloudformation
@cloudformation ||= Aws::CloudFormation::Client.new
end
def ensure_deleted!
stack = get_stack
return if stack.nil?
return if TERMINATED_STATUSES.include? stack.stack_status
cloudformation.delete_stack(stack_name: @stack_name)
cloudformation.wait_until(:stack_delete_complete, stack_name: @stack_name) { |waiter| waiter.delay = @waiter_delay; waiter.max_attempts = @waiter_attempts }
end
def updatable?
stack = get_stack
return false if stack.nil?
return true if UPDATEABLE_STATUSES.include? stack.stack_status
return false if TERMINATED_STATUSES.include? stack.stack_status
if RECOVERABLE_STATUSES.include? stack.stack_status
ConsoleJockey.write_line "There's a previous stack called #{@stack_name} that didn't create properly, it will be deleted and rebuilt."
return false
end
raise UpdateError.new("Stack is in an unrecoverable state") if UNRECOVERABLE_STATUSES.include? stack.stack_status
raise UpdateError.new("Stack is busy, try again soon")
end
def create!(stack_config)
cloudformation.create_stack(
stack_name: @stack_name,
template_body: File.read(stack_config[:template_path]),
parameters: cf_params(stack_config, environment_config(stack_config)),
capabilities: ["CAPABILITY_IAM"],
on_failure: "DELETE"
)
begin
cloudformation.wait_until(:stack_create_complete, stack_name: @stack_name) { |waiter| waiter.delay = @waiter_delay; waiter.max_attempts = @waiter_attempts }
rescue Aws::Waiters::Errors::UnexpectedError => ex
handle_unexpected_error(ex)
end
end
def update!(stack_config)
wait_until_ready(false)
cloudformation.update_stack(
stack_name: @stack_name,
template_body: File.read(stack_config[:template_path]),
parameters: cf_params(stack_config, environment_config(stack_config)),
capabilities: ["CAPABILITY_IAM"]
)
cloudformation.wait_until(:stack_update_complete, stack_name: @stack_name) { |waiter| waiter.delay = @waiter_delay; waiter.max_attempts = @waiter_attempts }
rescue Aws::CloudFormation::Errors::ValidationError => ex
raise ex unless ex.message == "No updates are to be performed."
ConsoleJockey.write_line "No changes need to be applied for #{@stack_name}."
rescue Aws::Waiters::Errors::FailureStateError
ConsoleJockey.write_line "Failed to apply the environment update. The stack has been rolled back. It is still safe to apply updates."
ConsoleJockey.write_line "Find error details in the AWS CloudFormation console: #{stack_events_url}"
raise UpdateError.new("Stack update failed for #{@stack_name}.")
end
def environment_config(stack_config)
KumoConfig::EnvironmentConfig.new(stack_config)
end
def stack_events_url
"https://console.aws.amazon.com/cloudformation/home?region=#{ENV['AWS_DEFAULT_REGION']}#/stacks?filter=active&tab=events&stackId=#{get_stack.stack_id}"
end
def wait_until_ready(raise_on_error=true)
loop do
stack = get_stack(dump_cache: true)
if stack_ready?(stack.stack_status)
if raise_on_error && stack_operation_failed?(stack.stack_status)
raise stack.stack_status
end
break
end
puts "waiting for #{@stack_name} to be READY, current: #{last_event_status}"
sleep 10
end
rescue Aws::CloudFormation::Errors::ValidationError
nil
end
def stack_ready?(last_event_status)
last_event_status =~ /COMPLETE/ || last_event_status =~ /ROLLBACK_FAILED/
end
def stack_operation_failed?(last_event_status)
last_event_status =~ /ROLLBACK/
end
def handle_unexpected_error(error)
if error.message =~ /does not exist/
ConsoleJockey.write_line "There was an error during stack creation for #{@stack_name}, and the stack has been cleaned up."
raise CreateError.new("There was an error during stack creation. The stack has been deleted.")
else
raise error
end
end
def flash_message(message)
ConsoleJockey.flash_message(message)
end
end
end