fal Upload Asset Then Run Inference

arazzo: 1.0.1
info:
  title: fal Upload Asset Then Run Inference
  summary: Upload a binary reference asset to the fal CDN, then run an image-to-X model against it.
  description: >-
    Many fal models accept a reference image, audio clip, or control map by
    URL. This workflow first requests a signed upload URL from the fal Storage
    API, then submits an inference request that references the resulting public
    CDN file_url, polls the queue until the job completes, and returns the
    output. The actual PUT of the file bytes to the signed upload_url happens
    outside the orchestrated API steps and is noted where it occurs. 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: falStorageApi
  url: ../openapi/fal-storage-api-openapi.yml
  type: openapi
- name: falModelApis
  url: ../openapi/fal-model-apis-openapi.yml
  type: openapi
workflows:
- workflowId: upload-then-inference
  summary: Register an input asset on the fal CDN and feed its URL into a model.
  description: >-
    Initiates a signed upload to obtain a public CDN file_url, then submits an
    inference request that passes that file_url as the model's image_url input,
    waits for completion, and returns the result.
  inputs:
    type: object
    required:
    - contentType
    - fileName
    - modelOwner
    - modelName
    - prompt
    properties:
      contentType:
        type: string
        description: MIME type of the asset being uploaded (e.g. "image/png").
      fileName:
        type: string
        description: Original file name used to derive the CDN object name.
      modelOwner:
        type: string
        description: Owning organization of the model (e.g. "fal-ai").
      modelName:
        type: string
        description: Model identifier (e.g. "flux/dev/image-to-image").
      prompt:
        type: string
        description: Natural-language prompt describing the desired output.
  steps:
  - stepId: initiateUpload
    description: >-
      Request a short-lived signed upload URL and the public CDN file_url for
      the asset. The client PUTs the file bytes to upload_url out of band before
      the asset can be referenced by a model.
    operationId: initiateUpload
    requestBody:
      contentType: application/json
      payload:
        content_type: $inputs.contentType
        file_name: $inputs.fileName
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      uploadUrl: $response.body#/upload_url
      fileUrl: $response.body#/file_url
  - stepId: submitJob
    description: >-
      Submit an inference request that references the uploaded asset by its CDN
      file_url as the model's image_url input.
    operationId: submitRequest
    parameters:
    - name: model_owner
      in: path
      value: $inputs.modelOwner
    - name: model_name
      in: path
      value: $inputs.modelName
    requestBody:
      contentType: application/json
      payload:
        prompt: $inputs.prompt
        image_url: $steps.initiateUpload.outputs.fileUrl
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      requestId: $response.body#/request_id
  - stepId: pollStatus
    description: >-
      Poll the request status until the job reaches a terminal COMPLETED state,
      re-entering itself while still IN_QUEUE or IN_PROGRESS.
    operationId: getRequestStatus
    parameters:
    - name: model_owner
      in: path
      value: $inputs.modelOwner
    - name: model_name
      in: path
      value: $inputs.modelName
    - name: request_id
      in: path
      value: $steps.submitJob.outputs.requestId
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      status: $response.body#/status
    onSuccess:
    - name: completed
      type: goto
      stepId: fetchResult
      criteria:
      - context: $response.body
        condition: $.status == "COMPLETED"
        type: jsonpath
    - name: stillRunning
      type: goto
      stepId: pollStatus
      criteria:
      - context: $response.body
        condition: $.status == "IN_QUEUE" || $.status == "IN_PROGRESS"
        type: jsonpath
  - stepId: fetchResult
    description: >-
      Retrieve the final inference output for the completed request.
    operationId: getRequestResult
    parameters:
    - name: model_owner
      in: path
      value: $inputs.modelOwner
    - name: model_name
      in: path
      value: $inputs.modelName
    - name: request_id
      in: path
      value: $steps.submitJob.outputs.requestId
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      result: $response.body
  outputs:
    fileUrl: $steps.initiateUpload.outputs.fileUrl
    requestId: $steps.submitJob.outputs.requestId
    result: $steps.fetchResult.outputs.result