Google Cloud Async I/O Authentication Client

import asyncio
import os
import aiohttp
from gcloud.aio.auth import Token

async def main():
    # Attempt to use GOOGLE_APPLICATION_CREDENTIALS environment variable or ADC
    # For local development, ensure `gcloud auth application-default login` has been run
    # or GOOGLE_APPLICATION_CREDENTIALS points to a service account key file.
    service_account_path = os.environ.get('GOOGLE_APPLICATION_CREDENTIALS', '')
    
    print("Initializing Token...")
    # Initialize Token; it will try to discover credentials if service_file is None.
    # Specify necessary scopes for your application.
    token = Token(
        service_file=service_account_path if service_account_path else None,
        scopes=["https://www.googleapis.com/auth/cloud-platform"]
    )
    
    async with aiohttp.ClientSession() as session:
        try:
            # Get an access token (automatically refreshed by the Token instance)
            access_token = await token.get()
            print(f"Successfully obtained access token (first 10 chars): {access_token[:10]}...")
            
            # Example: Make an authenticated request to a Google Cloud API
            # (e.g., list buckets in Google Cloud Storage)
            headers = {"Authorization": f"Bearer {access_token}"}
            print("Making a dummy authenticated request to Google Cloud Storage API...")
            async with session.get(
                "https://www.googleapis.com/storage/v1/projects/_/buckets",
                headers=headers
            ) as response:
                if response.status == 200:
                    print(f"Request to GCS successful (status 200). Some buckets (if any): {await response.json()}")
                else:
                    print(f"Request failed with status: {response.status}")
                    print(f"Response body: {await response.text()}")
                    
        except Exception as e:
            print(f"An error occurred: {e}")
        finally:
            # Ensure the token's internal session is closed
            await token.close()

if __name__ == "__main__":
    asyncio.run(main())