Amazon EC2 Stop and Start Instance Cycle

arazzo: 1.0.1
info:
  title: Amazon EC2 Stop and Start Instance Cycle
  summary: Stop an instance, wait until stopped, then start it again and confirm running.
  description: >-
    Performs a full stop and start cycle, useful for changing instance
    attributes that require a stop. The workflow stops the instance, polls
    DescribeInstances until it reports stopped, starts it again, and confirms it
    returns to running. The poll steps branch on the instance state name. 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
workflows:
- workflowId: stop-start-instance-cycle
  summary: Cycle an instance through stopped and back to running.
  description: >-
    Chains StopInstances, a stopped-state poll, StartInstances, and a
    running-state poll, each branching on the instance state name.
  inputs:
    type: object
    required:
    - instanceId
    properties:
      instanceId:
        type: string
        description: The ID of the instance to stop and restart.
  steps:
  - stepId: stopInstance
    description: Stop the target instance.
    operationId: stopInstances
    parameters:
    - name: Action
      in: query
      value: StopInstances
    - name: Version
      in: query
      value: '2016-11-15'
    - name: InstanceId
      in: query
      value: $inputs.instanceId
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      stopStatus: $statusCode
  - stepId: pollStopped
    description: >-
      Describe the instance and branch on its state, looping while stopping and
      proceeding once it reports stopped.
    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: stillStopping
      type: goto
      stepId: pollStopped
      criteria:
      - context: $response.body
        condition: $.reservationSet[0].instancesSet[0].instanceState.name == 'stopping'
        type: jsonpath
    - name: nowStopped
      type: goto
      stepId: startInstance
      criteria:
      - context: $response.body
        condition: $.reservationSet[0].instancesSet[0].instanceState.name == 'stopped'
        type: jsonpath
  - stepId: startInstance
    description: Start the stopped instance again.
    operationId: startInstances
    parameters:
    - name: Action
      in: query
      value: StartInstances
    - name: Version
      in: query
      value: '2016-11-15'
    - name: InstanceId
      in: query
      value: $inputs.instanceId
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      startStatus: $statusCode
  - stepId: pollRunning
    description: >-
      Describe the instance and branch on its state, looping while pending and
      ending once it reports running.
    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: stillStarting
      type: goto
      stepId: pollRunning
      criteria:
      - context: $response.body
        condition: $.reservationSet[0].instancesSet[0].instanceState.name == 'pending'
        type: jsonpath
    - name: nowRunning
      type: end
      criteria:
      - context: $response.body
        condition: $.reservationSet[0].instancesSet[0].instanceState.name == 'running'
        type: jsonpath
  outputs:
    finalState: $steps.pollRunning.outputs.state