Class: Bosh::AwsCloud::ResourceWait

Inherits:
Object
  • Object
show all
Includes:
Helpers
Defined in:
lib/cloud/aws/resource_wait.rb

Constant Summary collapse

DEFAULT_TRIES =

a sane amount of retries on AWS (~25 minutes), as things can take anywhere between a minute and forever

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MAX_SLEEP_EXPONENT = 
5

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Helpers

#cloud_error, #extract_security_group_names

Constructor Details

#initialize ⇒ ResourceWait

Returns a new instance of ResourceWait.



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# File 'lib/cloud/aws/resource_wait.rb', line 150

def initialize
  @started_at = Time.now
end

Class Method Details

.for_attachment(args) ⇒ Object 



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# File 'lib/cloud/aws/resource_wait.rb', line 34

def self.for_attachment(args)
  attachment = args.fetch(:attachment) { raise ArgumentError, 'attachment object required' }
  target_state = args.fetch(:state) { raise ArgumentError, 'state symbol required' }
  valid_states = [:attached, :detached]
  validate_states(valid_states, target_state)

  ignored_errors = []
  if target_state == :attached
    ignored_errors << AWS::Core::Resource::NotFound
  end
  description = "volume %s to be %s to instance %s as device %s" % [
      attachment.volume.id, target_state, attachment.instance.id, attachment.device
  ]

  new.for_resource(resource: attachment, errors: ignored_errors, target_state: target_state, description: description) do |current_state|
    current_state == target_state
  end
rescue AWS::Core::Resource::NotFound
  # if an attachment is detached, AWS can reap the object and the reference is no longer found,
  # so consider this exception a success condition if we are detaching
  raise unless target_state == :detached
end

.for_image(args) ⇒ Object 



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# File 'lib/cloud/aws/resource_wait.rb', line 57

def self.for_image(args)
  image = args.fetch(:image) { raise ArgumentError, 'image object required' }
  target_state = args.fetch(:state) { raise ArgumentError, 'state symbol required' }
  valid_states = [:available, :deleted]
  validate_states(valid_states, target_state)

  ignored_errors = []
  if target_state == :available
    ignored_errors = [AWS::EC2::Errors::InvalidAMIID::NotFound]
  end

  new.for_resource(resource: image, errors: ignored_errors, target_state: target_state, state_method: :state) do |current_state|
    current_state == target_state
  end
rescue AWS::Core::Resource::NotFound
  # if an AMI is deleted, AWS can reap the object and the reference is no longer found,
  # so consider this exception a success condition if we are deleting
  raise unless target_state == :deleted
end

.for_instance(args) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/cloud/aws/resource_wait.rb', line 12

def self.for_instance(args)
  raise ArgumentError, "args should be a Hash, but `#{args.class}' given" unless args.is_a?(Hash)
  instance = args.fetch(:instance) { raise ArgumentError, 'instance object required' }
  target_state = args.fetch(:state) { raise ArgumentError, 'state symbol required' }
  valid_states = [:running, :terminated]
  validate_states(valid_states, target_state)

  ignored_errors = [
    AWS::EC2::Errors::InvalidInstanceID::NotFound,
    AWS::Core::Resource::NotFound
  ]

  new.for_resource(resource: instance, errors: ignored_errors, target_state: target_state) do |current_state|
    if target_state == :running && current_state == :terminated
      logger.error("instance #{instance.id} terminated while starting")
      raise Bosh::Clouds::VMCreationFailed.new(true)
    else
      current_state == target_state
    end
  end
end

.for_sgroup(args) ⇒ Object 



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# File 'lib/cloud/aws/resource_wait.rb', line 116

def self.for_sgroup(args)
  sgroup = args.fetch(:sgroup) { raise ArgumentError, 'sgroup object required' }
  target_state = args.fetch(:state) { raise ArgumentError, 'state symbol required' }
  valid_states = [true, false]
  validate_states(valid_states, target_state)

  new.for_resource(resource: sgroup, target_state: true, state_method: :exists?) do |current_state|
    current_state == target_state
  end
end

.for_snapshot(args) ⇒ Object 



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# File 'lib/cloud/aws/resource_wait.rb', line 92

def self.for_snapshot(args)
  snapshot = args.fetch(:snapshot) { raise ArgumentError, 'snapshot object required' }
  target_state = args.fetch(:state) { raise ArgumentError, 'state symbol required' }
  valid_states = [:completed]
  validate_states(valid_states, target_state)

  new.for_resource(resource: snapshot, target_state: target_state, tries: 18) do |current_state|
    current_state == target_state
  end
end

.for_subnet(args) ⇒ Object 



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# File 'lib/cloud/aws/resource_wait.rb', line 103

def self.for_subnet(args)
  subnet = args.fetch(:subnet) { raise ArgumentError, 'subnet object required' }
  target_state = args.fetch(:state) { raise ArgumentError, 'state symbol required' }
  valid_states = [:available]
  validate_states(valid_states, target_state)

  ignored_errors = [AWS::EC2::Errors::InvalidSubnetID::NotFound]

  new.for_resource(resource: subnet, target_state: target_state, errors: ignored_errors, state_method: :state) do |current_state|
    current_state == target_state
  end
end

.for_volume(args) ⇒ Object 



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# File 'lib/cloud/aws/resource_wait.rb', line 77

def self.for_volume(args)
  volume = args.fetch(:volume) { raise ArgumentError, 'volume object required' }
  target_state = args.fetch(:state) { raise ArgumentError, 'state symbol required' }
  valid_states = [:available, :deleted]
  validate_states(valid_states, target_state)

  new.for_resource(resource: volume, target_state: target_state) do |current_state|
    current_state == target_state
  end
rescue AWS::EC2::Errors::InvalidVolume::NotFound
  # if an volume is deleted, AWS can reap the object and the reference is no longer found,
  # so consider this exception a success condition if we are deleting
  raise unless target_state == :deleted
end

.logger ⇒ Object 



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# File 'lib/cloud/aws/resource_wait.rb', line 142

def self.logger
  Bosh::Clouds::Config.logger
end

.sleep_callback(description, tries) ⇒ Object 



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# File 'lib/cloud/aws/resource_wait.rb', line 133

def self.sleep_callback(description, tries)
  lambda do |num_tries, error|
    sleep_time = 2**[num_tries, MAX_SLEEP_EXPONENT].min # Exp backoff: 1, 2, 4, 8 ... up to max 32
    Bosh::AwsCloud::ResourceWait.logger.debug("#{error.class}: `#{error.message}'") if error
    Bosh::AwsCloud::ResourceWait.logger.debug("#{description}, retrying in #{sleep_time} seconds (#{num_tries}/#{tries})")
    sleep_time
  end
end

.task_checkpoint ⇒ Object 



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# File 'lib/cloud/aws/resource_wait.rb', line 146

def self.task_checkpoint
  Bosh::Clouds::Config.task_checkpoint
end

.validate_states(valid_states, target_state) ⇒ Object 



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# File 'lib/cloud/aws/resource_wait.rb', line 127

def self.validate_states(valid_states, target_state)
  unless valid_states.include?(target_state)
    raise ArgumentError, "target state must be one of #{valid_states.join(', ')}, `#{target_state}' given"
  end
end

Instance Method Details

#for_resource(args, &blk) ⇒ Object 



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# File 'lib/cloud/aws/resource_wait.rb', line 154

def for_resource(args, &blk)
  resource = args.fetch(:resource)
  state_method = args.fetch(:state_method, :status)
  errors = args.fetch(:errors, [])
  desc = args.fetch(:description) { resource.id }
  tries = args.fetch(:tries, DEFAULT_TRIES).to_i
  target_state = args.fetch(:target_state)

  sleep_cb = self.class.sleep_callback("Waiting for #{desc} to be #{target_state}", tries)
  errors << AWS::EC2::Errors::RequestLimitExceeded
  ensure_cb = Proc.new do |retries|
    cloud_error("Timed out waiting for #{desc} to be #{target_state}, took #{time_passed}s") if retries == tries
  end

  state = nil
  Bosh::Retryable.new(tries: tries, sleep: sleep_cb, on: errors, ensure: ensure_cb).retryer do
    Bosh::AwsCloud::ResourceWait.task_checkpoint

    state = resource.method(state_method).call
    if state == :error || state == :failed
      raise Bosh::Clouds::CloudError, "#{desc} state is #{state}, expected #{target_state}, took #{time_passed}s"
    end

    # the yielded block should return true if we have reached the target state
    blk.call(state)
  end

  Bosh::AwsCloud::ResourceWait.logger.info("#{desc} is now #{state}, took #{time_passed}s")
rescue Bosh::Common::RetryCountExceeded => e
  Bosh::AwsCloud::ResourceWait.logger.error(
    "Timed out waiting for #{desc} state is #{state}, expected to be #{target_state}, took #{time_passed}s")
  raise e
end

#time_passed ⇒ Object 



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# File 'lib/cloud/aws/resource_wait.rb', line 188

def time_passed
  Time.now - @started_at
end