Class: Convection::Control::Stack

Inherits:
Object
  • Object
show all
Defined in:
lib/convection/control/stack.rb

Overview

The Stack class provides a state wrapper for CloudFormation Stacks. It tracks the state of the managed stack, and creates/updates accordingly. Stack is also region-aware, and can be used within a template to define resources that depend upon availability-zones or other region-specific neuances that cannot be represented as maps or require iteration.

Constant Summary

CREATE_COMPLETE =

Represents a stack that has successfully been converged.

'CREATE_COMPLETE'.freeze
CREATE_FAILED =

Represents a stack that has not successfully been converged.

'CREATE_FAILED'.freeze
CREATE_IN_PROGRESS =

Represents a stack that is currently being converged for the first time.

'CREATE_IN_PROGRESS'.freeze
DELETE_COMPLETE =

Represents a stack that has successfully been deleted.

'DELETE_COMPLETE'.freeze
DELETE_FAILED =

Represents a stack that has not successfully been deleted.

'DELETE_FAILED'.freeze
DELETE_IN_PROGRESS =

Represents a stack that is currently being deleted.

'DELETE_IN_PROGRESS'.freeze
ROLLBACK_COMPLETE =

Represents a stack that has successfully been rolled back.

'ROLLBACK_COMPLETE'.freeze
ROLLBACK_FAILED =

Represents a stack that has not successfully been rolled back.

'ROLLBACK_FAILED'.freeze
ROLLBACK_IN_PROGRESS =

Represents a stack that is currently being rolled back.

'ROLLBACK_IN_PROGRESS'.freeze
UPDATE_COMPLETE =

Represents a stack that has successfully been updated (re-converged).

'UPDATE_COMPLETE'.freeze
UPDATE_COMPLETE_CLEANUP_IN_PROGRESS =

Represents a stack that is currently performing post-update cleanup.

'UPDATE_COMPLETE_CLEANUP_IN_PROGRESS'.freeze
UPDATE_FAILED =

Represents a stack that has not successfully been updated.

'UPDATE_FAILED'.freeze
UPDATE_IN_PROGRESS =

Represents a stack that is currently being updated (re-converged).

'UPDATE_IN_PROGRESS'.freeze
UPDATE_ROLLBACK_COMPLETE =

Represents a stack that has successfully rolled back an update (re-converge).

'UPDATE_ROLLBACK_COMPLETE'.freeze
UPDATE_ROLLBACK_COMPLETE_CLEANUP_IN_PROGRESS =

Represents a stack that is currently performing post-update-rollback cleanup.

'UPDATE_ROLLBACK_COMPLETE_CLEANUP_IN_PROGRESS'.freeze
UPDATE_ROLLBACK_FAILED =

Represents a stack that has successfully been rolled back after an update.

'UPDATE_ROLLBACK_FAILED'.freeze
UPDATE_ROLLBACK_IN_PROGRESS =

Represents a stack that is currently performing a update rollback.

'UPDATE_ROLLBACK_IN_PROGRESS'.freeze
NOT_CREATED =

Represents a stack that has not been created. The default state for a convection stack before getting its status.

'NOT_CREATED'.freeze
TASK_COMPLETE =

Represents a stack task being completed.

'TASK_COMPLETE'.freeze
TASK_FAILED =

Represents a stack task having failed.

'TASK_FAILED'.freeze
TASK_IN_PROGRESS =

Represents a stack task that is currently in progress.

'TASK_IN_PROGRESS'.freeze

Instance Attribute Summary collapse

Attribute accessors collapse

Stack state methods collapse

Render/diff methods collapse

Controllers collapse

Task methods collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, template, options = {}, &block) ⇒ Stack

rubocop:disable Metrics/LineLength

Parameters:

  • name (String) —

    the name of the CloudFormation Stack

  • template (Convection::Model::Template) —

    a wrapper of the CloudFormation template (can be rendered into CF JSON)

  • options (Hash) (defaults to: {}) —

    an options hash to pass in advanced configuration options. Undocumented options will be passed directly to CloudFormation's #create_stack or #update_stack.

Options Hash (options):

  • :region (String) —

    AWS region, format us-east-1. Default us-east-1

  • :credentials (Hash) —

    optional instance of `Aws::Credentials`

  • :parameters (Hash) —

    CloudFormation Stack parameters

  • :tags (String) —

    CloudFormation Stack tags

  • :on_failure (String) —

    the create failure action. Default: `DELETE`

  • :capabilities (Array<String>) —

    A list of capabilities (such as `CAPABILITY_IAM`). See also Aws::CloudFormation::Client#create_stack



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# File 'lib/convection/control/stack.rb', line 101

def initialize(name, template, options = {}, &block)
  @name = name
  @template = template.clone(self)
  @errors = []

  @cloud = options.delete(:cloud)
  @cloud_name = options.delete(:cloud_name)
  @region = options.delete(:region) { |_| 'us-east-1' }
  @credentials = options.delete(:credentials)
  @parameters = options.delete(:parameters) { |_| {} } # Default empty hash
  @tags = options.delete(:tags) { |_| {} } # Default empty hash
  options.delete(:disable_rollback) # There can be only one...
  @on_failure = options.delete(:on_failure) { |_| 'DELETE' }
  @capabilities = options.delete(:capabilities) { |_| ['CAPABILITY_IAM'] }

  @attributes = options.delete(:attributes) { |_| Model::Attributes.new }
  @options = options

  client_options = {}.tap do |opt|
    opt[:region] = @region
    opt[:credentials] = @credentials unless @credentials.nil?
  end
  @ec2_client = Aws::EC2::Client.new(client_options)
  @cf_client = Aws::CloudFormation::Client.new(client_options)

  ## Remote state
  @exist = false
  @status = NOT_CREATED
  @id = nil
  @outputs = {}
  @resources = {}
  @tasks = { after_create: [], after_delete: [], after_update: [], before_create: [], before_delete: [], before_update: [] }
  instance_exec(&block) if block
  @current_template = {}
  @last_event_seen = nil

  # First pass evaluation of stack
  # This is important because it:
  #   * Catches syntax errors before starting a converge
  #   * Builds a list of all resources that allows stacks early in
  #     the dependency tree to know about later stacks.  Some
  #     clouds use this, for example, to create security groups early
  #     in the dependency tree to avoid the chicken-and-egg problem.
  @template.execute

  ## Get initial state
  get_status(cloud_name)
  return unless exist?

  get_resources
  get_template
  resource_attributes
  get_events(1) # Get the latest page of events (Set @last_event_seen before starting)
rescue Aws::Errors::ServiceError => e
  @errors << e
end

Instance Attribute Details

#attribute_mapping_values ⇒ Object (readonly)

Returns the value of attribute attribute_mapping_values



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# File 'lib/convection/control/stack.rb', line 29

def attribute_mapping_values
  @attribute_mapping_values
end

#attributes ⇒ Object (readonly)

Returns the value of attribute attributes



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# File 'lib/convection/control/stack.rb', line 25

def attributes
  @attributes
end

#capabilities ⇒ Object (readonly)

Returns the value of attribute capabilities



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# File 'lib/convection/control/stack.rb', line 36

def capabilities
  @capabilities
end

#cloud ⇒ Object

Returns the value of attribute cloud



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# File 'lib/convection/control/stack.rb', line 35

def cloud
  @cloud
end

#credentials ⇒ Object

Returns the value of attribute credentials



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# File 'lib/convection/control/stack.rb', line 37

def credentials
  @credentials
end

#errors ⇒ Object (readonly)

Returns the value of attribute errors



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# File 'lib/convection/control/stack.rb', line 26

def errors
  @errors
end

#exist ⇒ Boolean (readonly) Also known as: exist?

Returns whether the stack exists and has a status other than DELETED.

Returns:

  • (Boolean) —

    whether the stack exists and has a status other than DELETED.



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# File 'lib/convection/control/stack.rb', line 20

def exist
  @exist
end

#id ⇒ Object (readonly)

Returns the value of attribute id



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# File 'lib/convection/control/stack.rb', line 15

def id
  @id
end

#name ⇒ Object (readonly)

Returns the value of attribute name



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# File 'lib/convection/control/stack.rb', line 16

def name
  @name
end

#on_failure ⇒ Object

Returns the value of attribute on_failure



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# File 'lib/convection/control/stack.rb', line 40

def on_failure
  @on_failure
end

#options ⇒ Object (readonly)

Returns the value of attribute options



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# File 'lib/convection/control/stack.rb', line 27

def options
  @options
end

#outputs ⇒ Object (readonly)

Returns the value of attribute outputs



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# File 'lib/convection/control/stack.rb', line 30

def outputs
  @outputs
end

#parameters ⇒ Object (readonly)

Returns the value of attribute parameters



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# File 'lib/convection/control/stack.rb', line 38

def parameters
  @parameters
end

#region ⇒ Object

AWS-SDK



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# File 'lib/convection/control/stack.rb', line 34

def region
  @region
end

#resources ⇒ Object (readonly)

Returns the value of attribute resources



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# File 'lib/convection/control/stack.rb', line 28

def resources
  @resources
end

#status ⇒ String (readonly)

Returns CloudFormation Stack status

Returns:

  • (String) —

    CloudFormation Stack status



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# File 'lib/convection/control/stack.rb', line 22

def status
  @status
end

#tags ⇒ Object (readonly)

Returns the value of attribute tags



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# File 'lib/convection/control/stack.rb', line 39

def tags
  @tags
end

#tasks ⇒ Object (readonly)

Returns the value of attribute tasks



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# File 'lib/convection/control/stack.rb', line 31

def tasks
  @tasks
end

#template ⇒ Object

Returns the value of attribute template



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# File 'lib/convection/control/stack.rb', line 17

def template
  @template
end

Instance Method Details

#[](key) ⇒ Object

See Also:



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# File 'lib/convection/control/stack.rb', line 179

def [](key)
  @attributes.get(name, key)
end

#[]=(key, value) ⇒ Object

See Also:



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# File 'lib/convection/control/stack.rb', line 184

def []=(key, value)
  @attributes.set(name, key, value)
end

#after_create_task(task) ⇒ Object

Register a given task to run after creation of a stack.



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# File 'lib/convection/control/stack.rb', line 422

def after_create_task(task)
  @tasks[:after_create] << task
end

#after_delete_task(task) ⇒ Object

Register a given task to run after deletion of a stack.



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# File 'lib/convection/control/stack.rb', line 427

def after_delete_task(task)
  @tasks[:after_delete] << task
end

#after_update_task(task) ⇒ Object

Register a given task to run after an update of a stack.



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# File 'lib/convection/control/stack.rb', line 432

def after_update_task(task)
  @tasks[:after_update] << task
end

#apply(&block) ⇒ Object

Render the CloudFormation template and apply the Stack using the CloudFormation client.

Parameters:

  • block (Proc) —

    a configuration block to pass any Model::Events to.



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# File 'lib/convection/control/stack.rb', line 292

def apply(&block)
  request_options = @options.clone.tap do |o|
    o[:template_body] = to_json
    o[:parameters] = cf_parameters
    o[:capabilities] = capabilities
  end

  # Get the state of existence before creation
  existing_stack = exist?
  if existing_stack
    if diff.empty? ## No Changes. Just get resources and move on
      block.call(Model::Event.new(:complete, "Stack #{ name } has no changes", :info)) if block
      get_status
      return
    elsif !resource_changes? && resource_dependent_changes?
      message = "Stack #{ name } has no convergable changes (you must update Resources to update Conditions, Metadata, or Outputs)"
      block.call(Model::Event.new(UPDATE_FAILED, message, :warn)) if block
      get_status
      return
    end

    ## Execute before update tasks
    @tasks[:before_update].delete_if do |task|
      run_task(:before_update, task, &block)
    end

    ## Update
    @cf_client.update_stack(request_options.tap do |o|
      o[:stack_name] = id
    end)
  else
    ## Execute before create tasks
    @tasks[:before_create].delete_if do |task|
      run_task(:before_create, task, &block)
    end

    ## Create
    @cf_client.create_stack(request_options.tap do |o|
      o[:stack_name] = cloud_name

      o[:tags] = cf_tags
      o[:on_failure] = on_failure
    end)

    get_status(cloud_name) # Get ID of new stack
  end

  watch(&block) if block # Block execution on stack status

  ## Execute after create tasks
  after_task_type = existing_stack ? :after_update : :after_create
  @tasks[after_task_type].delete_if do |task|
    run_task(after_task_type, task, &block)
  end
rescue Aws::Errors::ServiceError => e
  @errors << e
end

#availability_zones(&block) ⇒ Array<String>

Returns the list of availability zones found by the call to ec2 client's describe availability zones

Parameters:

  • block (Proc) —

    a block to pass each availability zone (with its index)

Returns:

  • (Array<String>) —

    the list of availability zones found by the call to ec2 client's describe availability zones



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# File 'lib/convection/control/stack.rb', line 402

def availability_zones(&block)
  @availability_zones ||=
    @ec2_client.describe_availability_zones.availability_zones.map(&:zone_name).sort

  @availability_zones.each_with_index(&block) if block
  @availability_zones
end

#before_create_task(task) ⇒ Object

Register a given task to run before creation of a stack.



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# File 'lib/convection/control/stack.rb', line 437

def before_create_task(task)
  @tasks[:before_create] << task
end

#before_delete_task(task) ⇒ Object

Register a given task to run before deletion of a stack.



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# File 'lib/convection/control/stack.rb', line 442

def before_delete_task(task)
  @tasks[:before_delete] << task
end

#before_update_task(task) ⇒ Object

Register a given task to run before an update of a stack.



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# File 'lib/convection/control/stack.rb', line 447

def before_update_task(task)
  @tasks[:before_update] << task
end

#cloud_name ⇒ Object

rubocop:enable Metrics/LineLength



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# File 'lib/convection/control/stack.rb', line 159

def cloud_name
  return @cloud_name unless @cloud_name.nil?
  return name if cloud.nil?
  "#{ cloud }-#{ name }"
end

#complete? ⇒ Boolean

Returns whether the CloudFormation Stack is in one of the several *_COMPLETE states.

Returns:

  • (Boolean) —

    whether the CloudFormation Stack is in one of the several *_COMPLETE states.



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# File 'lib/convection/control/stack.rb', line 208

def complete?
  [CREATE_COMPLETE, ROLLBACK_COMPLETE, UPDATE_COMPLETE, UPDATE_ROLLBACK_COMPLETE].include?(status)
end

#delete(&block) ⇒ Object

Delete the CloudFormation Stack using the CloudFormation client.

Parameters:

  • block (Proc) —

    a configuration block to pass any Model::Events to.



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# File 'lib/convection/control/stack.rb', line 354

def delete(&block)
  ## Execute before delete tasks
  @tasks[:before_delete].delete_if do |task|
    run_task(:before_delete, task, &block)
  end

  @cf_client.delete_stack(
    :stack_name => id
  )

  ## Block execution on stack status
  watch(&block) if block

  get_status

  ## Execute after delete tasks
  @tasks[:after_delete].delete_if do |task|
    run_task(:after_delete, task, &block)
  end
rescue Aws::Errors::ServiceError => e
  @errors << e
end

#diff ⇒ Hash

Returns a set of differences between the current template (in CloudFormation) and the state of the rendered template (what would be converged).

Returns:

  • (Hash) —

    a set of differences between the current template (in CloudFormation) and the state of the rendered template (what would be converged).

See Also:



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# File 'lib/convection/control/stack.rb', line 249

def diff
  @template.diff(@current_template)
end

#error? ⇒ Boolean

Returns whether any errors occurred modifying the stack.

Returns:

  • (Boolean) —

    whether any errors occurred modifying the stack.



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# File 'lib/convection/control/stack.rb', line 220

def error?
  !errors.empty?
end

#fail? ⇒ Boolean

Returns whether the CloudFormation Stack is in one of the several *_FAILED states.

Returns:

  • (Boolean) —

    whether the CloudFormation Stack is in one of the several *_FAILED states.



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# File 'lib/convection/control/stack.rb', line 214

def fail?
  [CREATE_FAILED, ROLLBACK_FAILED, DELETE_FAILED, UPDATE_ROLLBACK_FAILED].include?(status)
end

#get(*args) ⇒ Object

See Also:



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# File 'lib/convection/control/stack.rb', line 189

def get(*args)
  @attributes.get(*args)
end

#in_progress? ⇒ Boolean

Returns whether or not the CloudFormation Stack is in one of several *IN_PROGRESS states.

Returns:

  • (Boolean) —

    whether or not the CloudFormation Stack is in one of several *IN_PROGRESS states.



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# File 'lib/convection/control/stack.rb', line 199

def in_progress?
  [CREATE_IN_PROGRESS, ROLLBACK_IN_PROGRESS, DELETE_IN_PROGRESS,
   UPDATE_IN_PROGRESS, UPDATE_COMPLETE_CLEANUP_IN_PROGRESS,
   UPDATE_ROLLBACK_IN_PROGRESS,
   UPDATE_ROLLBACK_COMPLETE_CLEANUP_IN_PROGRESS].include?(status)
end

#include?(key) ⇒ Boolean #include?(stack_name, key) ⇒ Boolean

Returns whether the stack includes the specified key.

Overloads:

  • #include?(key) ⇒ Boolean

    Parameters:

    • key (String) —

      the name of the attribute to find

  • #include?(stack_name, key) ⇒ Boolean

    Parameters:

    • stack_name (String) —

      the name of the stack to check within

    • key (String) —

      the name of the attribute to find

Returns:

  • (Boolean) —

    whether the stack includes the specified key.



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# File 'lib/convection/control/stack.rb', line 173

def include?(stack, key = nil)
  return @attributes.include?(name, stack) if key.nil?
  @attributes.include?(stack, key)
end

#render ⇒ Object

See Also:



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# File 'lib/convection/control/stack.rb', line 234

def render
  @template.render
end

#resource_changes? ⇒ Boolean

Returns whether the Resources section of the rendered template has any changes compared to the current template (in CloudFormation).

Returns:

  • (Boolean) —

    whether the Resources section of the rendered template has any changes compared to the current template (in CloudFormation).



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# File 'lib/convection/control/stack.rb', line 256

def resource_changes?
  ours = { 'Resources' => @template.resources.map(&:render) }
  thiers = { 'Resources' => @current_template['Resources'] }

  ours.diff(thiers).any?
end

#resource_dependent_changes? ⇒ Boolean

Returns whether the any template sections dependent on the Resources section of the rendered template has any changes compared to the current template (in CloudFormation). For example Conditions, Metadata, and Outputs depend on changes to resources to be able to converge. See also rapid7/convection#140.

Returns:

  • (Boolean) —

    whether the any template sections dependent on the Resources section of the rendered template has any changes compared to the current template (in CloudFormation). For example Conditions, Metadata, and Outputs depend on changes to resources to be able to converge. See also rapid7/convection#140.



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# File 'lib/convection/control/stack.rb', line 270

def resource_dependent_changes?
  ours = {
    'Conditions' => @template.conditions.map(&:render),
    'Outputs' => @template.outputs.map(&:render)
  }
  theirs = {
    'Conditions' => @current_template['Conditions'],
    'Outputs' => @current_template['Outputs']
  }

  ours.diff(theirs).any?
end

#success? ⇒ Boolean

Returns whether the Stack state is now #complete? (with no errors present).

Returns:

  • (Boolean) —

    whether the Stack state is now #complete? (with no errors present).



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# File 'lib/convection/control/stack.rb', line 225

def success?
  !error? && complete?
end

#to_json(pretty = false) ⇒ Object

Returns the renedered CloudFormation Template JSON.

Parameters:

  • pretty (Boolean) (defaults to: false) —

    whether to to pretty-print the JSON output

Returns:

  • the renedered CloudFormation Template JSON.

See Also:



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# File 'lib/convection/control/stack.rb', line 241

def to_json(pretty = false)
  @template.to_json(nil, pretty)
end

#validate ⇒ Object

Validates a rendered template against the CloudFormation API.

Raises:

  • unless the validation was successful



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# File 'lib/convection/control/stack.rb', line 413

def validate
  result = @cf_client.validate_template(:template_body => template.to_json)
  fail result.context.http_response.inspect unless result.successful?
  puts "\nTemplate validated successfully"
end

#watch(poll = 2, &block) ⇒ Object

Loops through current events until the CloudFormation Stack has finished being modified.



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# File 'lib/convection/control/stack.rb', line 381

def watch(poll = 2, &block)
  get_status

  loop do
    get_events.reverse_each do |event|
      block.call(Model::Event.from_cf(event))
    end if block

    break unless in_progress?

    sleep poll
    get_status
  end
rescue Aws::Errors::ServiceError => e
  @errors << e
end