Amazon Elastic Load Balancing Poll Target Health Until Healthy

arazzo: 1.0.1
info:
  title: Amazon Elastic Load Balancing Poll Target Health Until Healthy
  summary: Register a target then poll its health until it reaches the healthy state.
  description: >-
    Registers a target with an existing target group and then polls
    describeTargetHealth, branching on the reported state. While the target is
    still in the initial state the flow loops back and checks again; once the
    target reports healthy the flow ends successfully, and if it reports
    unhealthy the flow ends in failure. Each step spells out its request inline
    so the flow can be read and executed without opening the underlying OpenAPI
    description. The Elastic Load Balancing v2 API uses the AWS query protocol,
    so every operation is a GET whose inputs are carried as query parameters
    rather than a request body.
  version: 1.0.0
sourceDescriptions:
- name: targetsApi
  url: ../openapi/amazon-elastic-load-balancing-targets-api-openapi.yml
  type: openapi
workflows:
- workflowId: poll-target-health-until-healthy
  summary: Register a target and poll its health, branching on the reported state.
  description: >-
    Chains registerTargets with a describeTargetHealth poll loop that retries
    while the target is initializing, ends when it becomes healthy, and fails
    fast if it becomes unhealthy.
  inputs:
    type: object
    required:
    - targetGroupArn
    - targetId
    properties:
      targetGroupArn:
        type: string
        description: The ARN of the existing target group to register into.
      targetId:
        type: string
        description: The ID of the target to register and monitor.
      targetPort:
        type: integer
        description: The port the target is listening on.
        default: 80
  steps:
  - stepId: registerTargets
    description: Register the target with the target group to begin health checks.
    operationId: registerTargets
    parameters:
    - name: TargetGroupArn
      in: query
      value: $inputs.targetGroupArn
    - name: Targets.member.1.Id
      in: query
      value: $inputs.targetId
    - name: Targets.member.1.Port
      in: query
      value: $inputs.targetPort
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      registered: $statusCode
  - stepId: checkHealth
    description: >-
      Poll the health of the registered target and branch on its reported
      state, retrying while it is still initializing.
    operationId: describeTargetHealth
    parameters:
    - name: TargetGroupArn
      in: query
      value: $inputs.targetGroupArn
    - name: Targets.member.1.Id
      in: query
      value: $inputs.targetId
    - name: Targets.member.1.Port
      in: query
      value: $inputs.targetPort
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      healthState: $response.body#/targetHealthDescriptions/0/targetHealth/state
      reason: $response.body#/targetHealthDescriptions/0/targetHealth/reason
    onSuccess:
    - name: targetHealthy
      type: end
      criteria:
      - context: $response.body
        condition: $.targetHealthDescriptions[0].targetHealth.state == "healthy"
        type: jsonpath
    - name: targetUnhealthy
      type: goto
      stepId: reportUnhealthy
      criteria:
      - context: $response.body
        condition: $.targetHealthDescriptions[0].targetHealth.state == "unhealthy"
        type: jsonpath
    - name: stillInitializing
      type: retry
      stepId: checkHealth
      retryAfter: 15
      retryLimit: 20
      criteria:
      - context: $response.body
        condition: $.targetHealthDescriptions[0].targetHealth.state == "initial"
        type: jsonpath
  - stepId: reportUnhealthy
    description: >-
      Confirm the unhealthy state by reading target health one last time so the
      failure reason is captured in the workflow outputs.
    operationId: describeTargetHealth
    parameters:
    - name: TargetGroupArn
      in: query
      value: $inputs.targetGroupArn
    - name: Targets.member.1.Id
      in: query
      value: $inputs.targetId
    - name: Targets.member.1.Port
      in: query
      value: $inputs.targetPort
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      healthState: $response.body#/targetHealthDescriptions/0/targetHealth/state
      reason: $response.body#/targetHealthDescriptions/0/targetHealth/reason
      description: $response.body#/targetHealthDescriptions/0/targetHealth/description
    onSuccess:
    - name: failOut
      type: end
  outputs:
    healthState: $steps.checkHealth.outputs.healthState
    unhealthyReason: $steps.reportUnhealthy.outputs.reason