Azure Blob storage trigger doesn't fire for large blobs

Question

I have a blob-triggered Azure Function. It perfectly works with blobs up to 1.1-1.2GB (and less). But when I upload a 1.8GB file to the same container, the function doesn't get triggered at all. There are no invocations after waiting for even 1-2 hours after uploading the file.

Any idea why this happens? Is there a limitation to the blob size based on the triggering action is performed?

Answer 1

Hi, @Mehdi Samsami

I have tried.

I created the default Azure Blob Storage trigger function (C# 6.0, Windows, consumption plan) according to the following, created a 2.0GB dummy file and uploaded it, and it worked.

https://learn.microsoft.com/en-us/azure/azure-functions/functions-bindings-storage-blob-trigger?tabs=in-process%2Cextensionv5&pivots=programming-language-csharp

   iwasa.takahito@hoge 0418blob % ls -lh  
   total 12403680  
   \-rw-------  1 iwasa.takahito  staff   2.0G  4 18 07:24 hoge2000mb  
     
   iwasa.takahito@hoge 0418blob % az storage blob upload --account-name iwasa0418uploadstorage --container-name hoge --name hoge2000mb --file hoge2000mb  
     
   :  
     
   In addition, setting the corresponding environment variables can avoid inputting credentials in your command. Please use --help to get more information about environment variable usage.  
   Finished[#############################################################]  100.0000%  
   {  
     "etag": "\"0x8DA20C1B6A71253\"",  
     "lastModified": "2022-04-17T22:29:19+00:00"  
   }  



   2022-04-17T22:29:28.744 [Information] Executing 'Functions.BlobTrigger1' (Reason='New blob detected: hoge/hoge2000mb', Id=d31d51d0-a5d8-4cb1-8edc-23ec51619107)  
   2022-04-17T22:29:28.744 [Information] Trigger Details: MessageId: ccd31c69-dc65-4a73-b55b-b86ae01f2de4, DequeueCount: 1, InsertionTime: 2022-04-17T22:29:28.000+00:00, BlobCreated: 2022-04-17T22:29:19.000+00:00, BlobLastModified: 2022-04-17T22:29:19.000+00:00  
   2022-04-17T22:29:28.745 [Information] C# Blob trigger function Processed blobName:hoge2000mbSize: 2097152000 Bytes  
   2022-04-17T22:29:28.745 [Information] Executed 'Functions.BlobTrigger1' (Succeeded, Id=d31d51d0-a5d8-4cb1-8edc-23ec51619107, Duration=7ms)  

We need to find the conditions for reproducing the phenomenon.
Can you see the difference between the default function and your workload and find the reproducibility conditions?

Answer 2

@Mehdi Samsami ,

I provided an answer to similar question in the below thread, please check and see if it helps.

https://learn.microsoft.com/en-us/answers/questions/815020/azure-blob-storage-trigger-function-not-firing-whe.html?childToView=816297#answer-816297

Answer 3

Hi, @Mehdi Samsami

I'm looking for documentation on trigger conditions now, but the Azure Functions Consumption plan has a memory size limit of 1.5GB.

https://learn.microsoft.com/en-us/azure/azure-functions/functions-bindings-storage-blob-trigger?tabs=in-process%2Cextensionv5&pivots=programming-language-csharp#concurrency-and-memory-usage

You can take advantage of more memory by changing to the App Service plan, so it may be resolved if the trigger condition is related to this limitation.

Answer 4

Hi @Takahito Iwasa

Thanks a lot for trying to reproduce the issue!

Here are the configurations I use for the Azure Function:

• Stack: Python 3.8
• OS: Linux
• Runtime version: ~3 (I also tested ~4)
• App Service Plan: EP3

function.json:

   json  
   {  
     "scriptFile": "__init__.py",  
     "bindings": [  
       {  
         "name": "myblob",  
         "type": "blobTrigger",  
         "direction": "in",  
         "path": "daily-data/{name}",  
         "connection": "storagesimulationprod_STORAGE"  
       }  
     ]  
   }  

host.json:

   json  
   {  
     "version": "2.0",  
     "logging": {  
       "applicationInsights": {  
         "samplingSettings": {  
           "isEnabled": true,  
           "excludedTypes": "Request"  
         }  
       }  
     },  
     "extensionBundle": {  
       "id": "Microsoft.Azure.Functions.ExtensionBundle",  
       "version": "[2.*, 3.0.0)"  
     },  
     "functionTimeout": -1  
   }  

Also, now that I look at the Metrics details, I see that the function has been triggered, but nothing has happened. There are no invocation logs corresponding to these executions, which I haven't been noticed since now:

Answer 5

@Mehdi Samsami ,

Did you ever find the root cause? I am seeing similar behavior and am wondering if I need to switch to an Event Grid notification.