Blob trigger not working when new file arrives in the blob storage. The files are still kept in the blob storage

Question

Blob trigger not working when new file arrives in the blob storage. The files are still kept in the blob storage

Ayush Mishra 60

The blob trigger functions doesn't triggers whenever a new files arrives. It works randomly sometimes and rest it doesn't processes the files

Below is my host.json
{

  "version": "2.0",
  "logging": {
    "applicationInsights": {
      "samplingSettings": {
        "isEnabled": true,
        "excludedTypes": "Request"
      }
    }
  },
  "extensionBundle": {
    "id": "Microsoft.Azure.Functions.ExtensionBundle",
    "version": "[4.0.0, 5.0.0)"
  },
  "concurrency": {
    "dynamicConcurrencyEnabled": true,
    "snapshotPersistenceEnabled": true
  }
}

Below is function.json

{
  "scriptFile": "__init__.py",
  "bindings": [
    {
      "name": "myblob",
      "type": "blobTrigger",
      "direction": "in",
      "path": "amerex-raw-files/{name}",
      "connection": "ccarbonproddata_STORAGE"
    }
  ]
}

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Answer 1

Krishna Chowdary Paricharla 2,915 Microsoft External Staff Moderator

Hi Ayush Mishra •,

Your time-triggered approach to scan and process blobs is valid and gives you more control. To improve it:

Track processed blobs (e.g., using metadata or a database) to avoid duplicates.
Use blob metadata/tags to mark completion.
Optimize the cron interval for performance.
Add error handling and retries for reliability.
Consider parallel processing for large blob sets.

Krishna Chowdary Paricharla 2,915 Reputation points Microsoft External Staff Moderator

2025-07-08T05:38:44.5833333+00:00
Hello Ayush Mishra •

Blob Triggers sometimes miss events, especially under load or if files are uploaded using unsupported methods. So, use Event Grid + Queue Trigger for More Reliable Processing

Configure your Storage Account to emit Blob Created events to Azure Event Grid.

Set Event Grid to push events to an Azure Storage Queue.

Use an Azure Function with Queue Trigger to process the messages.

This pattern ensures every blob upload is reliably tracked and queued, and your function processes only fully uploaded files.

Step 1: Enable Event Grid on Blob Storage

Ensure the storage account is Event Grid-enabled.

Step 2: Send Event Grid Events to a Queue

Create a Queue (e.g., blob-events-queue)

Set up an Event Subscription on your Blob Container or Storage Account:

Event Type: BlobCreated

Endpoint Type: Storage QueueStep

Step 3: Use a Queue-Triggered Azure Function

Bind the Azure Function to the queue (blob-events-queue) and process the blob metadata from the message.

For your reference, please follow the below documentation:

Subscribe to blob created events using Event Grid

Create an Event Subscription to Storage Queue

Azure Functions - Queue trigger

Azure Blob storage trigger for Azure Functions

Hope this helps!
Krishna Chowdary Paricharla 2,915 Reputation points Microsoft External Staff Moderator

2025-07-09T06:05:26.63+00:00

Hello Ayush Mishra •,

Just checking in to see if you've had a chance to review my previous response and let me know if you have any additional questions.
Ayush Mishra 60 Reputation points

2025-07-09T07:07:55.5833333+00:00

Hi Krishna,

I tried implementing it but had few issues creating a new Queue-Triggered Azure Function app.
I thought of an approach for a time triggered function, which lists all blobs in a container, fetches data for each blob and then processes it, kept the cron schedule at very small intervals. Can you suggest any feedbacks or any other modification i can make to it. With this process, i can keep track of all blobs in a container, without missing any. In any case i have your suggested approach as a main backup i can look to.
Krishna Chowdary Paricharla 2,915 Reputation points Microsoft External Staff Moderator

2025-07-10T05:06:09.8166667+00:00

Hello Ayush Mishra •,

Just checking in to see if you've had a chance to review my previous response and let me know if you have any additional questions.
Krishna Chowdary Paricharla 2,915 Reputation points Microsoft External Staff Moderator

2025-07-11T05:04:04.6866667+00:00

Hello Ayush Mishra •,
I wanted to follow up to see if you’ve had an opportunity to look over my earlier response. Please let me know if you have any further questions.
Krishna Chowdary Paricharla 2,915 Reputation points Microsoft External Staff Moderator

2025-07-13T06:07:24.7033333+00:00

Hello Ayush Mishra •,

Thank you for the upvote! 😊, kindly consider clicking "Accept the answer" — this helps others in the community who might be looking for similar information. Appreciate your engagement!
Ayush Mishra 60 Reputation points

2025-07-15T07:04:23.2466667+00:00

Thanks it helped!
Krishna Chowdary Paricharla 2,915 Reputation points Microsoft External Staff Moderator

2025-07-15T07:06:27.6766667+00:00

Hello Ayush Mishra •,

Thank you for the upvote! 😊, kindly consider clicking "Accept the answer" — this helps others in the community who might be looking for similar information. Appreciate your engagement!