I working in Python project that has next asyncio operartions. I want to make sure each level has good error handling and comes back to main loop for repeated execution. I want to set like, I there is any error, I want the pnding tasks to be cancelled.

import asyncio

async def fetch_data_from_service(service_name):
    await asyncio.sleep(1)  # Simulating I/O operation
    if service_name == "ServiceB":
        raise Exception(f"Error fetching data from {service_name}")
    return f"Data from {service_name}"

async def process_data(data):
    await asyncio.sleep(1)  # Simulating data processing
    if data == "Data from ServiceC":
        raise Exception("Error processing data from ServiceC")
    return f"Processed {data}"

async def main_task():
    try:
        dataA = await fetch_data_from_service("ServiceA")
        dataB = await fetch_data_from_service("ServiceB")
        dataC = await fetch_data_from_service("ServiceC")
        
        processedA = await process_data(dataA)
        processedB = await process_data(dataB)
        processedC = await process_data(dataC)

        print(processedA, processedB, processedC)
    except Exception as e:
        print(f"Exception caught in main_task: {e}")
        # How to ensure all pending tasks are canceled if an error occurs?
        # How to propagate this error back to the main event loop?

# Running the event loop
if __name__ == "__main__":
    try:
        asyncio.run(main_task())
    except Exception as e:
        print(f"Exception caught in event loop: {e}")

I want efficient nest handling, each level checking, that task cancellation if error occurs, and error redirection to main event loop.

I wrapped each op in try-expect block to catch and manage errors. But, I’m not sure about that cancellation process.

I expect to manage async tasks without errors, eventhough an error occurs, call all taks and divert to main event loop.

Please, help me with this.