Addressing Limitations in Python Function Execution Model with Asyncio Event Loop in Azure Functions

Description:

We have identified foundational limitations in the Python function execution model within the Azure Functions Python Worker that have impacted multiple durable Python customers. The current model runs all asynchronous function calls within a single asyncio event loop, leading to several constraints and challenges that need to be addressed:

Execution Order of Invocations:

The order in which invocations are received and executed is subject to the scheduling logic of the asyncio event loop, resulting in potentially random execution order. Currently, we cannot guarantee a first-come, first-served execution model.
Invocation Timeout Tracking:

There is no mechanism for tracking the real status of an invocation when it times out. The timeout could result from a genuinely long-running invocation, or it might be due to the worker not picking up the invocation for an extended period (e.g., 15 minutes) because the event loop is busy with other tasks. Additionally, the loop may become stuck processing one or more "bad" async calls (i.e., calls declared as async but performing blocking operations). The Function Host sends the request to the worker and begins measuring the timeout, but there is no explicit acknowledgment, status check, or fast-fail mechanism for these bad async calls currently in place.
Monitoring Event Loop Status:

Currently, there is no platform support for real-time monitoring of the asyncio event loop's running status or the ability to take snapshots to diagnose potential issues.
Reference to the relevant code: https://github.com/Azure/azure-functions-python-worker/blob/b734c57b3b81b3cad2f84951ee79c3a493504e32/azure_functions_worker/dispatcher.py#L659C13-L669C62

These challenges present significant difficulties for customers relying on durable/ non durable Python functions, and we are looking for potential enhancements to address these limitations.

++ @davidmrdavid @andystaples @vrdmr @gavin-aguiar @hallvictoria @fabiocav

### Expected Behavior

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### Relevant sample code snipped

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### Additional Information

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Inizia da azure_functions_worker/dispatcher.py, intorno alle righe 659-669, e traccia come vengono pianificate e gestite le invocazioni asincrone. Chiarisci il comportamento previsto per l’ordine delle invocazioni, il monitoraggio dello stato di timeout, il fallimento rapido delle chiamate asincrone bloccanti e il monitoraggio del ciclo degli eventi prima di modificare il codice. Il lavoro si considera completato quando i miglioramenti concordati sono implementati con un comportamento verificabile, ma attualmente l’issue non fornisce criteri di accettazione o test specifici.

Scritto dal modello di indicizzazione a partire dal testo della issue.