I've got an Azure isolated function like so:

    [Function("TransactionEventsIntegration")]
    [ExponentialBackoffRetry(maxRetryCount: 3, minimumInterval: "00:00:02", maximumInterval: "00:05:00")]
    [ServiceBusOutput("%Transactions:SB:Transactions:ProcessorUpdateQueue%", Connection = "Transactions:SB:Transactions")]
    public async Task<ServiceBusMessage> Process(
        [ServiceBusTrigger(
            "%Transactions:SB:Transactions:ReceiveTopic%",
            "%Transactions:SB:Transactions:TransactionEventsTopicSubscription%",
            Connection = "Transactions:SB:Transactions")]
        ServiceBusReceivedMessage message,
        ServiceBusMessageActions messageActions,
        Microsoft.Azure.WebJobs.ExecutionContext executionContext)
    {
        // code
    }

This returns the following error:

Invalid use of a retry attribute. Check that the attribute is used on a trigger that supports function-level retry. ()

I've got an Azure isolated function like so:

    [Function("TransactionEventsIntegration")]
    [ExponentialBackoffRetry(maxRetryCount: 3, minimumInterval: "00:00:02", maximumInterval: "00:05:00")]
    [ServiceBusOutput("%Transactions:SB:Transactions:ProcessorUpdateQueue%", Connection = "Transactions:SB:Transactions")]
    public async Task<ServiceBusMessage> Process(
        [ServiceBusTrigger(
            "%Transactions:SB:Transactions:ReceiveTopic%",
            "%Transactions:SB:Transactions:TransactionEventsTopicSubscription%",
            Connection = "Transactions:SB:Transactions")]
        ServiceBusReceivedMessage message,
        ServiceBusMessageActions messageActions,
        Microsoft.Azure.WebJobs.ExecutionContext executionContext)
    {
        // code
    }

This returns the following error:

Invalid use of a retry attribute. Check that the attribute is used on a trigger that supports function-level retry. (https://aka.ms/azfw-rules?ruleid=AZFW0012)

• azure
• azure-functions-isolated
• dotnet-isolated

1 Answer 1

The Service Bus trigger in function app does not support function level retry, but you can configure retry in the Binding extension level for all the functions.

• Following the link in the error message, https://aka.ms/azfw-rules?ruleid=AZFW0012, it goes to below page :

Rule description
This rule is triggered in two scenarios:

A retry strategy is not recognized (only Fixed Delay and Exponential Backoff are supported)
A retry attribute is used on a trigger type that does not support function-level retry.
A list of triggers that support function-level retry can be found here.

• Then follow the link in here text, it takes us to https://learn.microsoft/en-us/azure/azure-functions/functions-bindings-error-pages?tabs=fixed-delay%2Cin-process%2Cnode-v4%2Cpython-v2&pivots=programming-language-csharp#retries

• Looking at the row in the table below, Service Bus does not support function level configuration for retry. It only supports Binding extension that you can configure in the host.json.

• To configure the host.json, you can follow the link in above table and go to https://learn.microsoft/en-us/azure/azure-functions/functions-bindings-service-bus?tabs=isolated-process%2Cextensionv5%2Cextensionv3&pivots=programming-language-csharp#hostjson-settings

{
    "version": "2.0",
    "extensions": {
        "serviceBus": {
            "clientRetryOptions":{
                "mode": "exponential",
                "tryTimeout": "00:01:00",
                "delay": "00:00:00.80",
                "maxDelay": "00:01:00",
                "maxRetries": 3
            },
            "prefetchCount": 0,
            ..........
        }
    }
}