Python Azure Functions, EventGrid Trigger

Question

I am pretty new to azure, and struggling with the python function triggers from eventGrid. I am using ready templates created from azure for python and getting errors. I will share the files.

(init.py)

import json
import logging

import azure.functions as func


def main(event: func.EventGridEvent):

    result = json.dumps(
        {
            "id": event.id,
            "data": event.get_json(),
            "topic": event.topic,
            "subject": event.subject,
            "event_type": event.event_type,
        }
    )

    logging.info("Python EventGrid trigger processed an event: %s", result)

function.json

{
  "bindings": [
    {
      "type": "eventGridTrigger",
      "name": "event",
      "direction": "in"
    }
  ],
  "disabled": false,
  "scriptFile": "__init__.py"
}

host.json

{
  "version": "2.0",
  "logging": {
    "applicationInsights": {
      "samplingSettings": {
        "isEnabled": true,
        "excludedTypes": "Request"
      }
    }
  },
  "extensionBundle": {
    "id": "Microsoft.Azure.Functions.ExtensionBundle",
    "version": "[2.*, 3.0.0)"
  }
}

and the that's the dataset that i sent to event grid

{
  "topic": "/subscriptions/{subscriptionID}/resourcegroups/{resourceGroupName}/providers/Microsoft.EventHub/namespaces/event",
  "subject": "eventhubs/test",
  "eventType": "captureFileCreated",
  "eventTime": "2017-07-14T23:10:27.7689666Z",
  "id": "{id}",
  "data": {
    "fileUrl": "https://test.blob.core.windows.net/debugging/testblob.txt",
    "fileType": "AzureBlockBlob",
    "partitionId": "1",
    "sizeInBytes": 0,
    "eventCount": 0,
    "firstSequenceNumber": -1,
    "lastSequenceNumber": -1,
    "firstEnqueueTime": "0001-01-01T00:00:00",
    "lastEnqueueTime": "0001-01-01T00:00:00"
  },
  "dataVersion": "", 
  "metadataVersion": "1" 
}

and the error that i am getting is

fail: Function.{functionName}[3]
Executed 'Functions.{functionName}' (Failed, Id={someID}, Duration=121ms)
Microsoft.Azure.WebJobs.Host.FunctionInvocationException: Exception while executing function: Functions.{functionName}
System.InvalidOperationException: Exception binding parameter 'event'
System.NotImplementedException: The method or operation is not implemented.

probably it is super easy mistake somewhere above but i couldn't find it..

Thanks in advance!

Answer 1

python fail: Function.{functionName}[3] Executed 'Functions.{functionName}' (Failed, Id={someID}, Duration=121ms) Microsoft.Azure.WebJobs.Host.FunctionInvocationException: Exception while executing function: Functions.{functionName} System.InvalidOperationException: Exception binding parameter 'event' System.NotImplementedException: The method or operation is not implemented.

The above error is quite a common generic error message. It appears when your application hits some limitations of the Event grid.

If It is reaching the maximum hits of limitations of Event Grid refer to this

Note: Event Grid triggers aren't natively supported in an internal load balancer App Service Environment. The trigger uses an HTTP request that can't reach the function app without a gateway into the virtual network.

If you are using a consumption plan try to use the dedicated plan to avoid this issue.

Refer here to reliable event processing to relate this error.

Check the limitations of Event Grid and choose the appropriate plan to for your requirement.

Reference:

azure function fails with function invocation exception