azure-func-sb-retry-4.cs

#r "Microsoft.ServiceBus"
using Microsoft.ServiceBus.Messaging;

using System;
using System.Threading.Tasks;

public static void RetryHandler(BrokeredMessage mySbMsg, Exception ex, TraceWriter log)
{
    RetryPolicy policy;

    // Mock out calling service to gather retry policy settings

    // Business errors policy
    if (ex.GetType() == typeof(ApplicationException))
    {
        policy = new RetryPolicy()
        {
            MaxRetryCount = 0,
            RetryInterval = 0
        };
    }
    // Protocol errors policy
    else if (ex.GetType() == typeof(TimeoutException))
    {
        policy = new RetryPolicy()
        {
            MaxRetryCount = 5,
            RetryInterval = 3000
        };
    }
    // Unsupported case
    else
    {
        // Take no action
        log.Info($"RetryHandler: No policy found. No action taken");
        return;
    }

    // Check message delivery count against policy
    if (mySbMsg.DeliveryCount >= policy.MaxRetryCount)
    {
        // Move message to dead letter queue
        mySbMsg.DeadLetter("Exceeded max retry policy", ex.Message);

        // Log action taken
        log.Info($"RetryHandler: Max delivery attempts {mySbMsg.DeliveryCount} exceeded. Message moved to dead letter queue");        
    }
    else
    {
        // Log action taken
        log.Info($"RetryHandler: Requeuing message. Delivery attempts {mySbMsg.DeliveryCount} of {policy.MaxRetryCount}");        

        // Sleep for the defined interval
        System.Threading.Thread.Sleep(policy.RetryInterval);

        // Throw the exception to trigger requeue
        throw ex;
    }
}

public class RetryPolicy
{
    public int MaxRetryCount { get; set;}
    public int RetryInterval { get; set;}
}