Why did our Azure Function suddenly fail to find the binding type 'blob'?

Robert Mann 0 Reputation points
2025-01-03T09:27:40.0466667+00:00

I have a python Azure function app that contains 3 timer triggers.

All three timer triggers make use of the blob binding.

The function.json looks like:

{
  "scriptFile": "__init__.py",
  "entryPoint": "main",
  "bindings": [
    {
      "name": "CalculateCommandTimer",
      "type": "timerTrigger",
      "direction": "in",
      "schedule": "*/1 * * * * *"
    },
    {
      "name": "inputblob",
      "type": "blob",
      "dataType": "string",
      "path": "config/config.json",
      "connection": "MyStorageAccount",
      "direction": "in"
    }
  ]
}

And the host.json looks like

{
  "version": "2.0",
  "extensionBundle": {
    "id": "Microsoft.Azure.Functions.ExtensionBundle",
    "version": "[3.*, 4.0.0)"
  }
}

Usually these functions run without issue. Last night at 2025-01-02 22:13:32 UTC all three suddenly gave the error

The 'CalculateCommandFunction' function is in error: The binding type(s) 'blob' were not found in the configured extension bundle. Please ensure the type is correct and the correct version of extension bundle is configured.

After this point all three timer triggers did nothing until 23:21 when the function app seems to have restarted itself.

Neither I nor any of my colleagues changed anything yesterday. So the issue can only lie with Azure.

So what happened here, and how can I prevent it happening again?

Azure Functions
Azure Functions
An Azure service that provides an event-driven serverless compute platform.
5,278 questions
0 comments No comments
{count} votes

1 answer

Sort by: Most helpful
  1. Pinaki Ghatak 5,485 Reputation points Microsoft Employee
    2025-01-06T09:25:53.91+00:00

    Hello @Robert Mann

    The error message you shared indicates that the 'blob' binding type was not found in the configured extension bundle. This can happen if the extension bundle version is not compatible with the 'blob' binding type or if the extension bundle is not installed correctly.

    Based on the host.json file you provided, it seems that you are using version 2.0 of the Azure Functions runtime and version [3.*, 4.0.0) of the extension bundle. However, it is possible that the extension bundle was not installed correctly or that there was an issue with the Azure Functions runtime.

    To prevent this issue from happening again, you can try the following steps:

    1. Check the Azure Functions runtime version and make sure it is compatible with the extension bundle version you are using.
    2. Check that the extension bundle is installed correctly and that all required extensions are included.
    3. If the issue persists, you can try updating the extension bundle to a newer version or downgrading to a previous version that is known to work with the 'blob' binding type.

    That should get you started.

    0 comments No comments

Your answer

Answers can be marked as Accepted Answers by the question author, which helps users to know the answer solved the author's problem.