app.yaml

runtime: python37
service: prototype

env_variables:
  STABILITY_HOST: "grpc.stability.ai:443"
  STABILITY_KEY: "sk-FDeORcjpafivBCYtq98HYaCpBJ7hbuhxoi4KZ0P1tr3Fs7Aq"
  CLOUD_STORAGE_BUCKET: "cdn.rifff.com"

handlers:
  - url: /api/.*
    script: auto
    secure: always
    login: admin

  - url: /(.*\.(gif|png|jpg|jpeg|ico|css|map|json|js|eot|svg|ttf|woff|woff2|ogg|mp3|wav|ogg|mp4|webm|xml|html|fbx|gltf))$
    static_files: public/\1
    upload: .*\.(gif|png|jpg|jpeg|ico|css|map|json|js|eot|svg|ttf|woff|woff2|ogg|mp3|wav|ogg|mp4|webm|xml|html|fbx|gltf)$

  - url: /.*
    static_files: public/index.html
    upload: public/index.html
    secure: always
    login: admin

main.py

import os
from flask import Flask
from flask_cors import CORS
from google.cloud import storage

from stability_sdk import client
import stability_sdk.interfaces.gooseai.generation.generation_pb2 as generation

import uuid

IMAGE_EXTENSIONS = { 'png', 'jpg', 'jpeg', 'gif' }

cs = storage.Client()

bucket = cs.bucket(os.environ['CLOUD_STORAGE_BUCKET'])

def allowed(filename: str):
    return '.' in filename and \
        filename.rsplit('.', 1)[1].lower() in IMAGE_EXTENSIONS

def upload(src: str, contents):
    blob = bucket.blob(src)
    blob.upload_from_string(contents)
    return { 'src': 'https://storage.googleapis.com/{}/{}'.format(os.environ['CLOUD_STORAGE_BUCKET'], src) }

#

app = Flask(__name__)
CORS(app)

stability = client.StabilityInference(
    key=os.environ['STABILITY_KEY'], 
    verbose=True,
)

#

@app.route('/api/prompt/<prompt>', methods=['GET'])
def on_prompt(prompt=None):
  if not isinstance(prompt, str):
    return { 'error': 'API Error: prompt does not exist.' }
  answers = stability.generate(
    prompt=prompt,
    seed=34567, # if provided, specifying a random seed makes results deterministic
    steps=30, # defaults to 50 if not specified
  )
  results = list()
  for resp in answers:
    for artifact in resp.artifacts:
      if artifact.finish_reason == generation.FILTER:
        return { 'error': 'API Error: Stable Diffusion safety filters. Please modify the prompt and try again.' }
      if artifact.type == generation.ARTIFACT_IMAGE:
        id = uuid.uuid4()
        data = upload('prompts/{}.png'.format(id), artifact.binary)
        results.append(data)
  return { 'results': results }

if __name__ == '__main__':
    # This is used when running locally only. When deploying to Google App
    # Engine, a webserver process such as Gunicorn will serve the app. You
    # can configure startup instructions by adding `entrypoint` to app.yaml.
    app.run(host='127.0.0.1', port=3000, debug=True)