How to use exponential back-off logic in Azure device client?

Hello Deepak !

Thank you for posting on Microsoft Learn.

The Azure IoT SDK for C# already supports retry policies, including exponential back-off, and you can apply them directly to your DeviceClient instance.

Add the required namespaces :

using Microsoft.Azure.Devices.Client; 
using Microsoft.Azure.Devices.Client.Retry;

Then, create the DeviceClient with an ExponentialBackoff RetryPolicy.

You need to instantiate the DeviceClient with exponential back-off:

TimeSpan minBackoff = TimeSpan.FromSeconds(1);
TimeSpan maxBackoff = TimeSpan.FromSeconds(60);
TimeSpan deltaBackoff = TimeSpan.FromSeconds(5);
int maxRetryCount = 5;

RetryPolicy retryPolicy = new ExponentialBackoff(maxRetryCount, minBackoff, maxBackoff, deltaBackoff);

DeviceClient deviceClient = DeviceClient.CreateFromConnectionString("YourConnectionString", TransportType.Mqtt);
deviceClient.SetRetryPolicy(retryPolicy);

• minBackoff: Minimum backoff duration between retries

maxBackoff: Maximum cap on the retry interval

deltaBackoff: Added randomness (jitter)

maxRetryCount: How many retries before giving up

You can monitor connection status (optional, for logging/debugging) :

deviceClient.SetConnectionStatusChangesHandler((status, reason) =>
{
    Console.WriteLine($"Connection status: {status}, Reason: {reason}");
});

Now that retries are handled by the SDK using exponential back-off, your timer logic should check if the client is Connected before doing work, and do nothing if it's retrying:

var status = deviceClient.GetConnectionStatus();
if (status == ConnectionStatus.Connected)
{
    // Do your work
}
else
{
    // Let the SDK handle retries; don't do anything here
    Console.WriteLine("Device is retrying connection, skipping this cycle.");
}