CloudFormation Create and Execute a Change Set

arazzo: 1.0.1
info:
  title: CloudFormation Create and Execute a Change Set
  summary: Create a change set, poll until CREATE_COMPLETE, execute it, then wait for the stack update to finish.
  description: >-
    Change sets let you preview how a template change will affect a running
    stack before committing it. This workflow creates a change set against an
    existing stack, polls DescribeChangeSet until the change set reaches
    CREATE_COMPLETE (branching to a failure end if creation fails), executes the
    change set, and then polls DescribeStacks until the resulting stack update
    settles into UPDATE_COMPLETE. Every step spells out its request inline using
    the AWS query protocol so the flow can be read and executed without opening
    the underlying OpenAPI description.
  version: 1.0.0
sourceDescriptions:
- name: cloudformationApi
  url: ../openapi/cloudformation-api.yml
  type: openapi
workflows:
- workflowId: change-set-deploy
  summary: Preview a stack change via a change set and execute it to completion.
  description: >-
    Creates a change set, waits for it to be created, executes it, and waits for
    the stack to reach UPDATE_COMPLETE.
  inputs:
    type: object
    required:
    - stackName
    - changeSetName
    - templateBody
    properties:
      stackName:
        type: string
        description: The name or unique ID of the existing stack to change.
      changeSetName:
        type: string
        description: The name to assign to the change set.
      templateBody:
        type: string
        description: The updated CloudFormation template body for the change set.
      capability:
        type: string
        description: An optional capability to acknowledge (e.g. CAPABILITY_IAM).
  steps:
  - stepId: createChangeSet
    description: >-
      Create a change set describing how the supplied template differs from the
      stack's current template.
    operationId: createChangeSet
    requestBody:
      contentType: application/x-www-form-urlencoded
      payload:
        StackName: $inputs.stackName
        ChangeSetName: $inputs.changeSetName
        TemplateBody: $inputs.templateBody
        ChangeSetType: UPDATE
        Capabilities:
        - $inputs.capability
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      changeSetId: $response.body#/CreateChangeSetResult/Id
      stackId: $response.body#/CreateChangeSetResult/StackId
  - stepId: pollChangeSet
    description: >-
      Poll DescribeChangeSet until the change set finishes computing. Branch to
      execution on CREATE_COMPLETE or to a failure end when creation fails.
    operationId: describeChangeSet
    requestBody:
      contentType: application/x-www-form-urlencoded
      payload:
        ChangeSetName: $inputs.changeSetName
        StackName: $inputs.stackName
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      changeSetStatus: $response.body#/Status
      statusReason: $response.body#/StatusReason
      changes: $response.body#/Changes
    onSuccess:
    - name: changeSetReady
      type: goto
      stepId: executeChangeSet
      criteria:
      - context: $response.body
        condition: $.Status == "CREATE_COMPLETE"
        type: jsonpath
    - name: changeSetFailed
      type: end
      criteria:
      - context: $response.body
        condition: $.Status == "FAILED"
        type: jsonpath
    - name: stillComputing
      type: goto
      stepId: pollChangeSet
      criteria:
      - context: $response.body
        condition: $.Status in ["CREATE_PENDING","CREATE_IN_PROGRESS"]
        type: jsonpath
  - stepId: executeChangeSet
    description: >-
      Execute the created change set, which starts updating the stack with the
      previewed changes.
    operationId: executeChangeSet
    requestBody:
      contentType: application/x-www-form-urlencoded
      payload:
        ChangeSetName: $inputs.changeSetName
        StackName: $inputs.stackName
    successCriteria:
    - condition: $statusCode == 200
  - stepId: pollStackUpdate
    description: >-
      Poll DescribeStacks until the stack update settles. End on UPDATE_COMPLETE
      or on any update rollback terminal state.
    operationId: describeStacks
    requestBody:
      contentType: application/x-www-form-urlencoded
      payload:
        StackName: $inputs.stackName
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      stackStatus: $response.body#/DescribeStacksResult/Stacks/0/StackStatus
    onSuccess:
    - name: updateDone
      type: end
      criteria:
      - context: $response.body
        condition: $.DescribeStacksResult.Stacks[0].StackStatus in ["UPDATE_COMPLETE","UPDATE_ROLLBACK_COMPLETE","UPDATE_ROLLBACK_FAILED"]
        type: jsonpath
    - name: stillUpdating
      type: goto
      stepId: pollStackUpdate
      criteria:
      - context: $response.body
        condition: $.DescribeStacksResult.Stacks[0].StackStatus in ["UPDATE_IN_PROGRESS","UPDATE_COMPLETE_CLEANUP_IN_PROGRESS","UPDATE_ROLLBACK_IN_PROGRESS"]
        type: jsonpath
  outputs:
    changeSetId: $steps.createChangeSet.outputs.changeSetId
    changes: $steps.pollChangeSet.outputs.changes
    finalStatus: $steps.pollStackUpdate.outputs.stackStatus