NASA Mars Rover Photo Harvest

arazzo: 1.0.1
info:
  title: NASA Mars Rover Photo Harvest
  summary: Read a rover's mission manifest to find a sol that actually has photos, then harvest that sol's images.
  description: >-
    The manifest-first pattern that keeps a Mars Rover Photos integration from
    blind-polling. Rovers do not photograph every sol, so requesting an
    arbitrary sol frequently returns an empty photo array. This workflow reads
    the mission manifest first, which reports the rover's status, its most
    recent sol, and its total photo count, harvests photos from that sol, and
    falls back to the dedicated latest_photos endpoint if the manifest sol still
    yields nothing. Every step spells out its request inline so the flow can be
    read and executed without opening the underlying OpenAPI description.
  version: 1.0.0
sourceDescriptions:
- name: nasaMarsRoverPhotosApi
  url: ../openapi/nasa-mars-rover-photos-openapi.yml
  type: openapi
workflows:
- workflowId: mars-rover-photo-harvest
  summary: Harvest photos from a Mars rover using its mission manifest to pick a productive sol.
  description: >-
    Reads a rover's mission manifest, uses the manifest's most recent sol to
    request photos, and falls back to the latest photos endpoint when that sol
    returns no images.
  inputs:
    type: object
    required:
    - rover
    - apiKey
    properties:
      rover:
        type: string
        description: The Mars rover to harvest photos from.
        enum:
        - curiosity
        - opportunity
        - spirit
      apiKey:
        type: string
        description: NASA API key from api.nasa.gov. DEMO_KEY works for low-volume testing.
        default: DEMO_KEY
      camera:
        type: string
        description: Optional camera abbreviation to filter photos by.
        enum:
        - FHAZ
        - RHAZ
        - MAST
        - CHEMCAM
        - MAHLI
        - MARDI
        - NAVCAM
        - PANCAM
        - MINITES
      page:
        type: integer
        description: Page of photo results to harvest, 25 photos per page.
        default: 1
  steps:
  - stepId: readMissionManifest
    description: >-
      Read the rover's mission manifest. This reports whether the rover is still
      active, the highest sol for which imagery exists, the corresponding Earth
      date, and the total photo count, which is the only reliable way to pick a
      sol that will return photos.
    operationId: getRoverManifest
    parameters:
    - name: rover
      in: path
      value: $inputs.rover
    - name: api_key
      in: query
      value: $inputs.apiKey
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      roverName: $response.body#/photo_manifest/name
      roverStatus: $response.body#/photo_manifest/status
      maxSol: $response.body#/photo_manifest/max_sol
      maxDate: $response.body#/photo_manifest/max_date
      totalPhotos: $response.body#/photo_manifest/total_photos
      landingDate: $response.body#/photo_manifest/landing_date
  - stepId: harvestPhotosForSol
    description: >-
      Request photos for the most recent sol reported by the manifest,
      optionally narrowed to a single camera. Results are paginated at 25 photos
      per page.
    operationId: getRoverPhotos
    parameters:
    - name: rover
      in: path
      value: $inputs.rover
    - name: sol
      in: query
      value: $steps.readMissionManifest.outputs.maxSol
    - name: camera
      in: query
      value: $inputs.camera
    - name: page
      in: query
      value: $inputs.page
    - name: api_key
      in: query
      value: $inputs.apiKey
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      photos: $response.body#/photos
      firstPhotoId: $response.body#/photos/0/id
      firstPhotoUrl: $response.body#/photos/0/img_src
      firstPhotoEarthDate: $response.body#/photos/0/earth_date
      firstPhotoCamera: $response.body#/photos/0/camera/full_name
    onSuccess:
    - name: photosHarvested
      type: end
      criteria:
      - context: $response.body
        condition: $.photos.length > 0
        type: jsonpath
    - name: solReturnedNothing
      type: goto
      stepId: fallbackToLatestPhotos
      criteria:
      - context: $response.body
        condition: $.photos.length == 0
        type: jsonpath
  - stepId: fallbackToLatestPhotos
    description: >-
      When the manifest sol returns no photos for the requested camera or page,
      fall back to the rover's dedicated latest photos endpoint, which always
      returns the most recently available imagery without needing a sol.
    operationId: getLatestRoverPhotos
    parameters:
    - name: rover
      in: path
      value: $inputs.rover
    - name: api_key
      in: query
      value: $inputs.apiKey
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      latestPhotos: $response.body#/latest_photos
      latestPhotoUrl: $response.body#/latest_photos/0/img_src
      latestPhotoSol: $response.body#/latest_photos/0/sol
      latestPhotoEarthDate: $response.body#/latest_photos/0/earth_date
  outputs:
    roverName: $steps.readMissionManifest.outputs.roverName
    roverStatus: $steps.readMissionManifest.outputs.roverStatus
    maxSol: $steps.readMissionManifest.outputs.maxSol
    totalPhotos: $steps.readMissionManifest.outputs.totalPhotos
    photos: $steps.harvestPhotosForSol.outputs.photos
    fallbackPhotos: $steps.fallbackToLatestPhotos.outputs.latestPhotos