CloudFormation Safe Stack Update

arazzo: 1.0.1
info:
  title: CloudFormation Safe Stack Update
  summary: Summarize a template, update the stack, poll until UPDATE_COMPLETE, then pull the stack events.
  description: >-
    A direct (non-change-set) stack update with guardrails. The workflow first
    asks GetTemplateSummary to surface the capabilities and parameters the
    template requires, then calls UpdateStack, polls DescribeStacks until the
    update settles into UPDATE_COMPLETE (branching to an event review on
    rollback), and finally pulls the recent stack events so the caller can audit
    exactly what happened during the update. 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: safe-stack-update
  summary: Summarize, apply, and audit an in-place CloudFormation stack update.
  description: >-
    Inspects the template summary, updates the stack, waits for the update to
    finish, and retrieves the stack events for auditing.
  inputs:
    type: object
    required:
    - stackName
    - templateBody
    properties:
      stackName:
        type: string
        description: The name or unique ID of the stack to update.
      templateBody:
        type: string
        description: The updated CloudFormation template body to apply.
      capability:
        type: string
        description: An optional capability to acknowledge (e.g. CAPABILITY_IAM).
  steps:
  - stepId: summarizeTemplate
    description: >-
      Get the template summary to surface required capabilities and declared
      parameters before applying the update.
    operationId: getTemplateSummary
    requestBody:
      contentType: application/x-www-form-urlencoded
      payload:
        TemplateBody: $inputs.templateBody
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      requiredCapabilities: $response.body#/GetTemplateSummaryResult/Capabilities
      parameters: $response.body#/GetTemplateSummaryResult/Parameters
  - stepId: updateStack
    description: >-
      Apply the updated template to the stack. After this call returns the stack
      update has started and can be polled via DescribeStacks.
    operationId: updateStack
    requestBody:
      contentType: application/x-www-form-urlencoded
      payload:
        StackName: $inputs.stackName
        TemplateBody: $inputs.templateBody
        Capabilities:
        - $inputs.capability
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      stackId: $response.body#/UpdateStackResult/StackId
  - stepId: pollStackUpdate
    description: >-
      Poll DescribeStacks until the update settles, then proceed to pull events
      whether the update succeeded or rolled back.
    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: updateSettled
      type: goto
      stepId: pullEvents
      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
  - stepId: pullEvents
    description: >-
      Retrieve the recent stack events in reverse chronological order so the
      update can be audited resource by resource.
    operationId: describeStackEvents
    requestBody:
      contentType: application/x-www-form-urlencoded
      payload:
        StackName: $inputs.stackName
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      stackEvents: $response.body#/DescribeStackEventsResult/StackEvents
  outputs:
    stackId: $steps.updateStack.outputs.stackId
    finalStatus: $steps.pollStackUpdate.outputs.stackStatus
    stackEvents: $steps.pullEvents.outputs.stackEvents