Canvas LMS Grade One of Many Submissions

arazzo: 1.0.1
info:
  title: Canvas LMS Grade One of Many Submissions
  summary: List an assignment's submissions, then post a grade to the first one returned.
  description: >-
    A grading flow for Canvas. The workflow lists the submissions for an
    assignment, takes the first submission's user id, and posts a grade and
    comment to that submission. It models the inner loop of bulk grading, where a
    grader walks the submission list and marks each one in turn. 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: canvasApi
  url: ../openapi/canvas-lms-rest-api-openapi.yml
  type: openapi
workflows:
- workflowId: grade-first-submission
  summary: Retrieve an assignment's submissions and grade the first one.
  description: >-
    Lists the submissions for an assignment, reads the first submission's user
    id, and posts a grade plus optional comment to that user's submission.
  inputs:
    type: object
    required:
    - courseId
    - assignmentId
    - postedGrade
    properties:
      courseId:
        type: string
        description: The Canvas course id.
      assignmentId:
        type: string
        description: The Canvas assignment id whose submissions are graded.
      postedGrade:
        type: string
        description: The grade to post to the first submission.
      textComment:
        type: string
        description: Optional feedback comment to attach.
  steps:
  - stepId: listSubmissions
    description: >-
      List the submissions for the assignment, including submission comments.
    operationId: listSubmissions
    parameters:
    - name: course_id
      in: path
      value: $inputs.courseId
    - name: assignment_id
      in: path
      value: $inputs.assignmentId
    - name: include[]
      in: query
      value:
      - submission_comments
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      firstUserId: $response.body#/0/user_id
  - stepId: gradeFirstSubmission
    description: >-
      Post the supplied grade and optional comment to the first submission's
      user.
    operationId: gradeSubmission
    parameters:
    - name: course_id
      in: path
      value: $inputs.courseId
    - name: assignment_id
      in: path
      value: $inputs.assignmentId
    - name: user_id
      in: path
      value: $steps.listSubmissions.outputs.firstUserId
    requestBody:
      contentType: application/json
      payload:
        submission:
          posted_grade: $inputs.postedGrade
        comment:
          text_comment: $inputs.textComment
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      grade: $response.body#/grade
      score: $response.body#/score
      userId: $response.body#/user_id
  outputs:
    userId: $steps.gradeFirstSubmission.outputs.userId
    grade: $steps.gradeFirstSubmission.outputs.grade