Amazon Rekognition Detect then Compare Faces

arazzo: 1.0.1
info:
  title: Amazon Rekognition Detect then Compare Faces
  summary: Confirm a face exists in the source image, then compare it against every face in a target image.
  description: >-
    A one-to-one face matching flow for Amazon Rekognition. The workflow runs
    DetectFaces on the source image to confirm exactly one usable face is
    present, then calls CompareFaces to measure similarity between the source
    face and each face detected in the target image. Each step spells out its
    AWS JSON 1.1 request inline, including the protocol-required X-Amz-Target
    header.
  version: 1.0.0
sourceDescriptions:
- name: rekognitionApi
  url: ../openapi/amazon-rekognition-openapi.yml
  type: openapi
workflows:
- workflowId: detect-then-compare-faces
  summary: Detect a source face then compare it against a target image.
  description: >-
    Verifies a face is present in the source image and then compares that face
    against all faces detected in the target image, returning similarity scores.
  inputs:
    type: object
    required:
    - sourceBucket
    - sourceName
    - targetBucket
    - targetName
    properties:
      sourceBucket:
        type: string
        description: S3 bucket holding the source image.
      sourceName:
        type: string
        description: S3 object key of the source image.
      targetBucket:
        type: string
        description: S3 bucket holding the target image.
      targetName:
        type: string
        description: S3 object key of the target image.
      similarityThreshold:
        type: number
        description: Minimum similarity for a match to be returned.
        default: 80.0
  steps:
  - stepId: detectSourceFace
    description: Confirm a face is present in the source image before comparing.
    operationId: detectFaces
    parameters:
    - name: X-Amz-Target
      in: header
      value: RekognitionService.DetectFaces
    requestBody:
      contentType: application/x-amz-json-1.1
      payload:
        Image:
          S3Object:
            Bucket: $inputs.sourceBucket
            Name: $inputs.sourceName
        Attributes:
        - DEFAULT
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      faceDetails: $response.body#/FaceDetails
    onSuccess:
    - name: sourceFaceFound
      type: goto
      stepId: compareFaces
      criteria:
      - context: $response.body
        condition: $.FaceDetails[0] empty false
        type: jsonpath
  - stepId: compareFaces
    description: Compare the source face against every face detected in the target image.
    operationId: compareFaces
    parameters:
    - name: X-Amz-Target
      in: header
      value: RekognitionService.CompareFaces
    requestBody:
      contentType: application/x-amz-json-1.1
      payload:
        SourceImage:
          S3Object:
            Bucket: $inputs.sourceBucket
            Name: $inputs.sourceName
        TargetImage:
          S3Object:
            Bucket: $inputs.targetBucket
            Name: $inputs.targetName
        SimilarityThreshold: $inputs.similarityThreshold
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      faceMatches: $response.body#/FaceMatches
      unmatchedFaces: $response.body#/UnmatchedFaces
  outputs:
    sourceFaceDetails: $steps.detectSourceFace.outputs.faceDetails
    faceMatches: $steps.compareFaces.outputs.faceMatches