Class: Moonshot::Tools::ASGRollout::ASG

Inherits:
Object
  • Object
show all
Defined in:
lib/moonshot/tools/asg_rollout/asg.rb

Overview

Abstration layer with AWS Auto Scaling Groups, for the Rollout tool.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name) ⇒ ASG

Returns a new instance of ASG.



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# File 'lib/moonshot/tools/asg_rollout/asg.rb', line 11

def initialize(name)
  @name = name
  @last_seen_ids = []
end

Instance Attribute Details

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/moonshot/tools/asg_rollout/asg.rb', line 9

def name
  @name
end

Instance Method Details

#current_max_and_desired ⇒ Object 



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# File 'lib/moonshot/tools/asg_rollout/asg.rb', line 16

def current_max_and_desired
  asg = load_asg

  [asg.max_size, asg.desired_capacity]
end

#detach_instance(id, decrement:) ⇒ Object 



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# File 'lib/moonshot/tools/asg_rollout/asg.rb', line 58

def detach_instance(id, decrement:)
  # Store the current instance IDs for the next call to wait_for_new_instance.
  load_asg

  resp = autoscaling.detach_instances(
    auto_scaling_group_name: @name,
    instance_ids: [id],
    should_decrement_desired_capacity: decrement)

  activity = resp.activities.first
  unless activity
    raise 'Did not receive Activity from DetachInstances call!'
  end

  # Wait for the detach activity to complete:
  loop do
    resp = autoscaling.describe_scaling_activities(
      auto_scaling_group_name: @name)

    current_status = resp.activities
                         .find { |a| a.activity_id == activity.activity_id }
                         .status_code

    case current_status
    when 'Failed', 'Cancelled'
      raise 'Detachment did not complete successfully!'
    when 'Successful'
      return
    end

    sleep 1
  end
end

#instance_health(id) ⇒ Object 



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# File 'lib/moonshot/tools/asg_rollout/asg.rb', line 92

def instance_health(id)
  elb_status = nil
  elb_status = elb_instance_state(id) if elb_name

  InstanceHealth.new(asg_instance_state(id), elb_status)
end

#non_conforming_instances ⇒ Object 



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# File 'lib/moonshot/tools/asg_rollout/asg.rb', line 29

def non_conforming_instances
  asg = load_asg

  asg.instances
     .select { |i| i.launch_configuration_name != asg.launch_configuration_name }
     .map(&:instance_id)
end

#set_max_and_desired(max, desired) ⇒ Object 



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# File 'lib/moonshot/tools/asg_rollout/asg.rb', line 22

def set_max_and_desired(max, desired)
  autoscaling.update_auto_scaling_group(
    auto_scaling_group_name: @name,
    max_size: max,
    desired_capacity: desired)
end

#wait_for_new_instance ⇒ Object 



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# File 'lib/moonshot/tools/asg_rollout/asg.rb', line 37

def wait_for_new_instance
  # Query the ASG until an instance appears which is not in
  # @last_seen_ids, then add it to @last_seen_ids and return
  # it.
  previous_ids = @last_seen_ids

  loop do
    load_asg

    new_ids = @last_seen_ids - previous_ids
    previous_ids = @last_seen_ids

    unless new_ids.empty?
      @last_seen_ids << new_ids.first
      return new_ids.first
    end

    sleep 3
  end
end