Amazon EC2 Deprovision a Secured Instance

arazzo: 1.0.1
info:
  title: Amazon EC2 Deprovision a Secured Instance
  summary: Terminate an instance, wait until terminated, then delete its security group.
  description: >-
    Tears down an instance and its dedicated security group in the correct
    order. The workflow terminates the instance, polls DescribeInstances until
    the instance reports the terminated state (deletion of a security group
    referenced by a live instance fails), and then deletes the security group.
    The poll step branches on the instance state name, looping while
    shutting-down and proceeding once terminated. Every step spells out its
    request inline using the Amazon EC2 query protocol (Action and Version
    parameters) so the flow can be read and executed without opening the
    underlying OpenAPI description.
  version: 1.0.0
sourceDescriptions:
- name: instancesApi
  url: ../openapi/amazon-ec2-instances-api-openapi.yml
  type: openapi
- name: securityGroupsApi
  url: ../openapi/amazon-ec2-security-groups-api-openapi.yml
  type: openapi
workflows:
- workflowId: deprovision-secured-instance
  summary: Terminate an instance and reclaim its security group once it is gone.
  description: >-
    Chains TerminateInstances, a DescribeInstances poll loop branching on the
    terminated state, and DeleteSecurityGroup to fully reclaim a secured
    instance footprint.
  inputs:
    type: object
    required:
    - instanceId
    - groupId
    properties:
      instanceId:
        type: string
        description: The ID of the instance to terminate.
      groupId:
        type: string
        description: The ID of the security group to delete after termination.
  steps:
  - stepId: terminateInstance
    description: Terminate the target instance.
    operationId: terminateInstances
    parameters:
    - name: Action
      in: query
      value: TerminateInstances
    - name: Version
      in: query
      value: '2016-11-15'
    - name: InstanceId
      in: query
      value: $inputs.instanceId
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      terminateStatus: $statusCode
  - stepId: pollTerminated
    description: >-
      Describe the instance and branch on its state, looping while shutting-down
      and proceeding once it reports terminated.
    operationId: describeInstances
    parameters:
    - name: Action
      in: query
      value: DescribeInstances
    - name: Version
      in: query
      value: '2016-11-15'
    - name: InstanceId
      in: query
      value: $inputs.instanceId
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      state: $response.body#/reservationSet/0/instancesSet/0/instanceState/name
    onSuccess:
    - name: stillShuttingDown
      type: goto
      stepId: pollTerminated
      criteria:
      - context: $response.body
        condition: $.reservationSet[0].instancesSet[0].instanceState.name == 'shutting-down'
        type: jsonpath
    - name: gone
      type: goto
      stepId: deleteSecurityGroup
      criteria:
      - context: $response.body
        condition: $.reservationSet[0].instancesSet[0].instanceState.name == 'terminated'
        type: jsonpath
  - stepId: deleteSecurityGroup
    description: Delete the now-unreferenced security group.
    operationId: deleteSecurityGroup
    parameters:
    - name: Action
      in: query
      value: DeleteSecurityGroup
    - name: Version
      in: query
      value: '2016-11-15'
    - name: GroupId
      in: query
      value: $inputs.groupId
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      deleteStatus: $statusCode
  outputs:
    finalState: $steps.pollTerminated.outputs.state
    deleteStatus: $steps.deleteSecurityGroup.outputs.deleteStatus