app.py

import os
import time
import json
import asyncio
import aiohttp
from aiohttp import web

PROJECT_ID = os.getenv('PROJECT_ID')
CLIENT_ID = os.getenv('CLIENT_ID')
CLIENT_SECRET = os.getenv('CLIENT_SECRET')
REFRESH_TOKEN = os.getenv('REFRESH_TOKEN')
API_KEY = os.getenv('API_KEY')

TOKEN_URL = 'https://www.googleapis.com/oauth2/v4/token'

token_cache = {
    'access_token': '',
    'expiry': 0,
    'refresh_promise': None
}

async def get_access_token():
    now = time.time()

    if token_cache['access_token'] and now < token_cache['expiry'] - 120:
        return token_cache['access_token']

    if token_cache['refresh_promise']:
        await token_cache['refresh_promise']
        return token_cache['access_token']

    async def refresh_token():
        async with aiohttp.ClientSession() as session:
            async with session.post(TOKEN_URL, json={
                'client_id': CLIENT_ID,
                'client_secret': CLIENT_SECRET,
                'refresh_token': REFRESH_TOKEN,
                'grant_type': 'refresh_token'
            }) as response:
                data = await response.json()
                token_cache['access_token'] = data['access_token']
                token_cache['expiry'] = now + data['expires_in']

    token_cache['refresh_promise'] = refresh_token()
    await token_cache['refresh_promise']
    token_cache['refresh_promise'] = None
    return token_cache['access_token']

def get_location():
    current_seconds = time.localtime().tm_sec
    return 'europe-west1' if current_seconds < 30 else 'us-east5'

def construct_api_url(location):
    return f'https://{location}-aiplatform.googleapis.com/v1/projects/{PROJECT_ID}/locations/{location}/publishers/anthropic/models/{MODEL}:streamRawPredict'

async def handle_request(request):
    if request.method == 'OPTIONS':
        return handle_options()

    api_key = request.headers.get('x-api-key')
    if api_key != API_KEY:
        error_response = web.Response(
            text=json.dumps({
                'type': 'error',
                'error': {
                    'type': 'permission_error',
                    'message': 'Your API key does not have permission to use the specified resource.'
                }
            }),
            status=403,
            content_type='application/json'
        )
        error_response.headers['Access-Control-Allow-Origin'] = '*'
        error_response.headers['Access-Control-Allow-Methods'] = 'POST, GET, OPTIONS, DELETE, HEAD'
        error_response.headers['Access-Control-Allow-Headers'] = 'Content-Type, Authorization, x-api-key, anthropic-version, model'
        return error_response

    access_token = await get_access_token()
    location = get_location()
    api_url = construct_api_url(location)

    request_body = await request.json()

    if 'anthropic_version' in request_body:
        del request_body['anthropic_version']
    if 'model' in request_body:
        del request_body['model']

    request_body['anthropic_version'] = 'vertex-2023-10-16'

    headers = {
        'Authorization': f'Bearer {access_token}',
        'Content-Type': 'application/json; charset=utf-8'
    }

    async with aiohttp.ClientSession() as session:
        async with session.post(api_url, json=request_body, headers=headers) as response:
            response_body = await response.read()
            response_headers = response.headers
            response_status = response.status

    modified_response = web.Response(
        body=response_body,
        status=response_status,
        headers=response_headers
    )
    modified_response.headers['Access-Control-Allow-Origin'] = '*'
    modified_response.headers['Access-Control-Allow-Methods'] = 'POST, GET, OPTIONS'
    modified_response.headers['Access-Control-Allow-Headers'] = 'Content-Type, Authorization, x-api-key, anthropic-version, model'

    return modified_response

def handle_options():
    headers = {
        'Access-Control-Allow-Origin': '*',
        'Access-Control-Allow-Methods': 'POST, GET, OPTIONS',
        'Access-Control-Allow-Headers': 'Content-Type, Authorization, x-api-key, anthropic-version, model'
    }
    return web.Response(status=204, headers=headers)

app = web.Application()
app.router.add_route('*', '/', handle_request)

if __name__ == '__main__':
    web.run_app(app, port=8080)