I am using the generate_content_async function to generate text from images asynchronously. The function works perfectly in Google Colab but does not behave as expected in a Flask app. On second call getting error as "Event loop is closed"

Gemini API
1

Code Implementation

Image Description Function

`type or paste code here`

async def describe_local_images():

    for img_filename in img_filenames:

        img = PIL.Image.open(img_filename)

        r = await model.generate_content_async([prompt, img])

        print(r.text)

await describe_local_images()

This works as expected in Colab but fails in the Flask environment.

Workaround in Flask

To handle the event loop issue, I implemented the following workaround:

python CopyEdit

def run_async_process(coroutine, *args, **kwargs):

    """Safely runs the given coroutine in a new event loop."""

    try:

        # Create a new event loop

        loop = asyncio.new_event_loop()

        asyncio.set_event_loop(loop)

        # Run the coroutine

        asyncio.run(process_image(*args, **kwargs))

    finally:

        # Ensure the loop is closed properly

        loop.close()

async def process_image(imgs, model, prompt, document_id):

    jobs = asyncio.gather(

        *[process_image_util(img, model, prompt) for img in imgs]

    )

    results = await jobs

    mongo.db.extracted_text.insert_one({

        "document_id": document_id,

        "text_data": json.dumps(results),

        "date": datetime.datetime.utcnow()

    })

async def process_image_util(img: str, model, prompt_main) -> str:

    doc_name = img.split(os.sep)[-2]

    page_no = img.split(os.sep)[-1]

    try:

        r = await model.generate_content_async([prompt_main, PIL.Image.open(img)])

        return {"doc_name": doc_name, "doc_text": r.text, "page_no": page_no}

    except Exception as e:

        print("Error processing image:", e)

        return {"doc_name": doc_name, "doc_text": "error", "page_no": page_no}

Even with this workaround, the generate_content_async function seems to rely on the first event loop, causing failures when the loop is closed or reused.

Error : Event loop is closed

  1. Why does generate_content_async behave differently in Colab versus a Flask app?

Environment Details
• Module: google.generativeai
• Function: generate_content_async
• Framework: Flask
• Python Version: 3.10.14
• Additional Libraries: PIL, asyncio

reference : cookbook/quickstarts/Asynchronous_requests.ipynb at main · google-gemini/cookbook · GitHub