Amazon Fargate Decommission a Cluster

arazzo: 1.0.1
info:
  title: Amazon Fargate Decommission a Cluster
  summary: Scale a service to zero and delete it, then delete the cluster once it has no active services.
  description: >-
    Fully retires a Fargate cluster and its single service. ECS will not delete a
    cluster that still has active services, so the workflow scales the service to
    zero, deletes it, polls DescribeClusters until the active service count
    reaches zero, and then deletes the cluster. Each step inlines its AWS JSON
    1.1 request and the X-Amz-Target action header so the decommission can be
    read and executed directly.
  version: 1.0.0
sourceDescriptions:
- name: fargateApi
  url: ../openapi/amazon-fargate-openapi.yml
  type: openapi
workflows:
- workflowId: decommission-cluster
  summary: Remove a service and then delete its cluster once no active services remain.
  description: >-
    Chains updateService (desiredCount 0), deleteService, a describeClusters
    poll until activeServicesCount is zero, and deleteCluster.
  inputs:
    type: object
    required:
    - cluster
    - service
    properties:
      cluster:
        type: string
        description: Name or ARN of the cluster to decommission.
      service:
        type: string
        description: Name or ARN of the service to remove first.
  steps:
  - stepId: scaleServiceToZero
    description: Scale the service to zero tasks so it can be deleted.
    operationId: updateService
    parameters:
    - name: X-Amz-Target
      in: header
      value: AmazonEC2ContainerServiceV20141113.UpdateService
    requestBody:
      contentType: application/x-amz-json-1.1
      payload:
        cluster: $inputs.cluster
        service: $inputs.service
        desiredCount: 0
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      serviceArn: $response.body#/service/serviceArn
  - stepId: deleteService
    description: Delete the now-zeroed service, forcing removal if needed.
    operationId: deleteService
    parameters:
    - name: X-Amz-Target
      in: header
      value: AmazonEC2ContainerServiceV20141113.DeleteService
    requestBody:
      contentType: application/x-amz-json-1.1
      payload:
        cluster: $inputs.cluster
        service: $inputs.service
        force: true
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      serviceStatus: $response.body#/service/status
  - stepId: pollClusterServices
    description: >-
      Poll DescribeClusters until the active service count reaches zero, then
      proceed to delete the cluster.
    operationId: describeClusters
    parameters:
    - name: X-Amz-Target
      in: header
      value: AmazonEC2ContainerServiceV20141113.DescribeClusters
    requestBody:
      contentType: application/x-amz-json-1.1
      payload:
        clusters:
        - $inputs.cluster
        include:
        - STATISTICS
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      clusterArn: $response.body#/clusters/0/clusterArn
      activeServicesCount: $response.body#/clusters/0/activeServicesCount
    onSuccess:
    - name: servicesRemain
      type: goto
      stepId: pollClusterServices
      criteria:
      - context: $response.body
        condition: $.clusters[0].activeServicesCount > 0
        type: jsonpath
    - name: cleared
      type: goto
      stepId: deleteCluster
      criteria:
      - context: $response.body
        condition: $.clusters[0].activeServicesCount == 0
        type: jsonpath
  - stepId: deleteCluster
    description: Delete the cluster now that it has no active services.
    operationId: deleteCluster
    parameters:
    - name: X-Amz-Target
      in: header
      value: AmazonEC2ContainerServiceV20141113.DeleteCluster
    requestBody:
      contentType: application/x-amz-json-1.1
      payload:
        cluster: $inputs.cluster
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      clusterArn: $response.body#/cluster/clusterArn
      finalStatus: $response.body#/cluster/status
  outputs:
    deletedServiceArn: $steps.scaleServiceToZero.outputs.serviceArn
    clusterArn: $steps.deleteCluster.outputs.clusterArn
    finalStatus: $steps.deleteCluster.outputs.finalStatus