Functions runtime won't start with "func start" locally

Question

Functions runtime won't start with "func start" locally

Anni 20

I have installed Python, VS code, Python and Azure Extensions, node.js, Azure Functions Core Tools and Azurite emulator. I have created azure function. When I'm trying to start locally using "func start", it doesn't start, I only get:

Found Python version 3.12.5 (py).

Azure Functions Core Tools

Core Tools Version: 4.0.6821 Commit hash: N/A +c09a2033faa7ecf51b3773308283af0ca9a99f83 (64-bit)

Function Runtime Version: 4.1036.1.23224

MS_FUNCTION_LOGS 5,,,,,ScriptApplicationHostOptionsSetup,"","ScmRunFromPackage is empty.",4.1036.1.23224,2025-01-23T07:06:29.6575321Z,,"",,,,RFQ-FILES,,,,

Language Worker Process exited. Pid=12704.

py exited with code -1073741819 (0xC0000005). .

PublishSpecializationCompleteEvent failed with System.InvalidOperationException: An invalid request URI was provided. Either the request URI must be an absolute URI or BaseAddress must be set.

at System.Net.Http.HttpClient.PrepareRequestMessage(HttpRequestMessage request)

at System.Net.Http.HttpClient.SendAsync(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationToken cancellationToken)

at Microsoft.Azure.WebJobs.Script.WebHost.Management.MeshServiceClient.SendAsync(IEnumerable`1 formData) in /_/src/WebJobs.Script.WebHost/Management/MeshServiceClient.cs:line 154

at Microsoft.Azure.WebJobs.Script.WebHost.Management.MeshServiceClient.NotifyHealthEvent(ContainerHealthEventType healthEventType, Type source, String details) in /_/src/WebJobs.Script.WebHost/Management/MeshServiceClient.cs:line 104

at Microsoft.Azure.WebJobs.Script.WebHost.ContainerManagement.LinuxContainerActivityPublisher.PublishSpecializationCompleteEvent() in /_/src/WebJobs.Script.WebHost/ContainerManagement/LinuxContainerActivityPublisher.cs:line 122

Starting worker process failed

Microsoft.Azure.WebJobs.Script.Grpc: The operation has timed out.

Failed to start language worker process for runtime: python. workerId:01e33c9f-cdf4-4c7c-af84-5403aefc2a36

Removing errored webhost language worker channel for runtime: python workerId:01e33c9f-cdf4-4c7c-af84-5403aefc2a36

Microsoft.Azure.WebJobs.Script.Grpc: The operation has timed out.

Khadeer Ali 5,990 Reputation points Microsoft External Staff Moderator

2025-01-23T13:45:41.1366667+00:00
@Anni

Welcome to the Microsoft Q&A Platform!

Thanks for reaching out. It looks like you're having trouble starting the Azure Functions runtime locally with the "func start" command. The error messages suggest there might be issues with the Python worker process, possibly due to the Python version or your Azure Functions setup.

Here are some steps to help you troubleshoot:

Check Python Version: Make sure you're using a compatible Python version with Azure Functions. Python 3.12.5 is pretty new and might have some compatibility issues. Try using Python 3.8 or 3.9, which are known to work well.

Update Azure Functions Core Tools: Ensure you have the latest version of Azure Functions Core Tools. You mentioned your version is 4.0.6821; see if there's a newer version available.

Verify Function Configuration: Double-check that your function app is set up correctly, especially the local.settings.json file, and that all required settings are there.

Run Azurite: If your function needs Azure Storage services, make sure the Azurite emulator is running before you start the function host.

Check for Additional Logs: Look for more detailed logs that might give extra context for the error. Enable verbose logging for more insights.

Try Running in a Virtual Environment: Run the command in a Python virtual environment to avoid conflicts with global packages.

If you're still having issues after these steps, check out the Azure Functions documentation or community forums for more specific help.

References:

References:

Develop Azure Functions locally using Core Tools (programming-language-python)

Develop Azure Functions locally using Core Tools (programming-language-csharp)

Hope this helps. Do let us know if you have any further queries.
Khadeer Ali 5,990 Reputation points Microsoft External Staff Moderator

2025-01-24T10:27:20.28+00:00

@Anni ,

I wanted to check in and see if my earlier response addressed your question. If you still need assistance or have additional questions, feel free to share more details.
Anni 20 Reputation points

2025-01-27T09:00:07.7366667+00:00

Thank you for quick response. System variables should not include "CONTAINER_NAME" named variable so removing this from computer solved this problem.
Reuben Anderson 0 Reputation points

2025-06-20T19:06:46.9433333+00:00

Is there a way a developer should know this? Is it included in the logging or?

Accepted answer

0 additional answers

Your answer

Khadeer Ali 5,990 Reputation points Microsoft External Staff Moderator

2025-01-23T13:45:41.1366667+00:00

@Anni

Welcome to the Microsoft Q&A Platform!

Thanks for reaching out. It looks like you're having trouble starting the Azure Functions runtime locally with the "func start" command. The error messages suggest there might be issues with the Python worker process, possibly due to the Python version or your Azure Functions setup.

Here are some steps to help you troubleshoot:

Check Python Version: Make sure you're using a compatible Python version with Azure Functions. Python 3.12.5 is pretty new and might have some compatibility issues. Try using Python 3.8 or 3.9, which are known to work well.

Update Azure Functions Core Tools: Ensure you have the latest version of Azure Functions Core Tools. You mentioned your version is 4.0.6821; see if there's a newer version available.

Verify Function Configuration: Double-check that your function app is set up correctly, especially the local.settings.json file, and that all required settings are there.

Run Azurite: If your function needs Azure Storage services, make sure the Azurite emulator is running before you start the function host.

Check for Additional Logs: Look for more detailed logs that might give extra context for the error. Enable verbose logging for more insights.

Try Running in a Virtual Environment: Run the command in a Python virtual environment to avoid conflicts with global packages.

If you're still having issues after these steps, check out the Azure Functions documentation or community forums for more specific help.

References:

References:

Develop Azure Functions locally using Core Tools (programming-language-python)

Develop Azure Functions locally using Core Tools (programming-language-csharp)

Hope this helps. Do let us know if you have any further queries.
Khadeer Ali 5,990 Reputation points Microsoft External Staff Moderator

2025-01-24T10:27:20.28+00:00

@Anni ,

I wanted to check in and see if my earlier response addressed your question. If you still need assistance or have additional questions, feel free to share more details.
Anni 20 Reputation points

2025-01-27T09:00:07.7366667+00:00

Thank you for quick response. System variables should not include "CONTAINER_NAME" named variable so removing this from computer solved this problem.
Reuben Anderson 0 Reputation points

2025-06-20T19:06:46.9433333+00:00

Is there a way a developer should know this? Is it included in the logging or?

Answer 1

@Anni ,

I'm glad to hear that you were able to resolve your issue, and thank you for sharing your solution! It's great to see your contribution, as it helps others in the community who may face a similar issue.

Since the Microsoft Q&A community policy states, "The question author cannot accept their own answer—they can only accept answers by others," I'm reposting your solution here so you can mark it as accepted if it resolves your query:

Issue:

Functions runtime won't start with "func start" locally

Reposted Solution:

System variables should not include "CONTAINER_NAME" named variable so removing this from computer solved this problem.

If you have any further questions, feel free to reach out.

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Functions runtime won't start with "func start" locally

0 additional answers

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