Minimal durable entity function - can't get it to work: The function 'xxx' doesn't exist

Question

I copied this repository to set up a minimal durable entity function project but I am getting errors.

https://github.com/Azure/azure-functions-durable-python/tree/dev/samples/counter_entity

Code structure like this, and I want to stress that I didn't change any code from how it is distributed.

I have exactly the same folder structure, exactly the same code and configuration except my local.settings.json has a AzureWebJobsStorage that uses my own storage account connection string.

I then run 'func host start', then put this URL into my browser: [http://localhost:7071/api/orchestrators/Counter]

I get 500 internal error:

[2025-02-03T16:04:00.128Z] Executed 'Functions.DurableTrigger' (Failed, Id=b5911178-fb1a-4e46-bd92-6e0857a498c0, Duration=243ms)
[2025-02-03T16:04:00.129Z] System.Private.CoreLib: Exception while executing function: Functions.DurableTrigger. System.Private.CoreLib: Result: Failure
[2025-02-03T16:04:00.129Z] Exception: Exception: The function 'Counter' doesn't exist, is disabled, or is not an orchestrator function. Additional info: The following are the known orchestrator functions: 'DurableOrchestration'.
[2025-02-03T16:04:00.129Z] Stack:   File "/usr/lib/azure-functions-core-tools-4/workers/python/3.10/LINUX/X64/azure_functions_worker/dispatcher.py", line 659, in _handle__invocation_request

Python libraries:

azure-core              1.32.0      Microsoft Azure Core Library for Python
azure-functions         1.21.3      Azure Functions for Python
azure-functions-durable 1.2.10      Durable Functions For Python

Also I checked my storage account and I can see a few TestHubNameXXX are created in table/queue/blob. I assume they are generated by the durable function app.

Is it not possible to test durable entities locally?

Answer 1

Hi @ZZ Thank you for posting the question on this platform.

You are calling the wrong end point URL which is resulting in this error. If you look at the method signature of Counter and DurableOrchestation you will know that there is a difference between how there are defined and each server a different purpose.

Counter is defined as def entity_function(context: df.DurableEntityContext): It represents the context object for the entity function. It provides access to the entity's state, the name of the operation being performed, and any input parameters. It is used to manage the state of the entity and perform operations like adding to the counter, resetting it, or retrieving its current value

DurableOrchestration on the other hand is defined as def orchestrator_function(context: df.DurableOrchestrationContext): which represents the context object for the orchestration function. It provides access to the orchestration's state, history, and API for calling activity functions, signaling entities, and managing timers. It is essential for coordinating the workflow of the orchestration.

Since the endpoint http://localhost:7071/api/orchestrators/{functionName} expects an Orchestration function, it errors out when you point to Entity context. You would need to pass the DurableOrchestration while calling the end-point

http://127.0.0.1:7071/api/orchestrators/DurableOrchestration

You can retrieve the state of the Counter by calling the end-point http://localhost:7071/api/entity/Counter/myCounter. You would get a result similar to this

Hope this helps!

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