Azure Function app on blob storage event trigger

Hello Shubham Tekade, Azure Functions can trigger on Blob Storage events, but when using Azure Data Lake Storage (ADLS) Gen2, the approach differs slightly due to the use of Event Grid for event notifications.

Reference: Azure Functions Blob Trigger

Here’s a breakdown of how to resolve this issue:

1. Event Grid Integration with ADLS Gen2:
   • Unlike Blob Storage, which natively integrates with Azure Functions via blob triggers, ADLS Gen2 relies on Event Grid to emit events when data is added or modified.
   • If you're using ADLS Gen2, you will need to create an Event Grid subscription for the container that listens for events such as Microsoft.Storage.BlobCreated or Microsoft.Storage.BlobDeleted.
   • Reference: Azure Blob Storage as Event Grid source (includes ADLS Gen2 with hierarchical namespace)
2. Setting Up Event Grid Trigger:

Instead of using the standard Blob Trigger in the function app, you should use the Event Grid trigger. This trigger listens to events sent by Event Grid, which in turn listens to events generated by ADLS Gen2.

• Make sure that the Event Grid subscription is correctly configured to send events to the Azure Function App.
  • Reference: Azure Event Grid with Azure Functions

1. Permissions and Access:

Ensure the Azure Function has appropriate permissions to listen to events from Event Grid. This might involve granting the necessary roles to the Azure Function App for access to Event Grid.

• Confirm that the Event Grid subscription is correctly configured with the required permissions to push events from ADLS Gen2 to your function.
  • Reference: Azure Functions security and permissions

1. Troubleshooting:

Verify that the Event Grid subscription is correctly set up for the ADLS container. You can check the Event Grid logs for any issues with the event delivery.

• Ensure the correct function trigger type is used. In the case of ADLS Gen2, it should be an Event Grid trigger, not the default Blob trigger.
  • Reference: Troubleshoot Azure Event Grid delivery issues

Documentation:

• Azure Functions Event Grid
• Create a function in Azure that's triggered by Blob storage
• Tutorial: Trigger Azure Functions on blob containers using an event subscription

Hope this helps! Let me know if you have further questions.