C# Retry Pattern Example

This example in C# illustrates an implementation of the Retry pattern. The purpose of this method is to repeatedly attempt to execute a piece of code (referred to as the "main logic") until either the operation is successful or a specified number of retries has been reached.

public async Task RetryAsync()
{
  int retryCount = 3;
  int currentRetry = 0;

  for (;;)
  {
    try
    {
      // main logic here

      break; // Return or break.
    }
    catch (Exception ex)
    {
      currentRetry++;

      if (currentRetry > this.retryCount) throw;
    }

    await Task.Delay(TimeSpan.FromSeconds(5));
  }
}

Breakdown of the code:

1. Initialization
2. Infinite Loop (for (;;))
   • The method enters an infinite loop using a for loop without a condition, meaning it will continue indefinitely until explicitly broken out of.
   • Inside the loop:
     • If the main logic succeeds, the break statement is encountered, and the loop is exited.
     • If an exception occurs during the main logic execution (catch (Exception ex)), the catch block is executed.
3. Handling Exceptions
   • currentRetry++;: Increments the currentRetry counter each time an exception is caught.
   • Checks whether the number of retries (currentRetry) has exceeded the maximum allowed retries (retryCount).
     • If the maximum retries have been reached, the exception is rethrown using throw;, propagating it further.
     • If the maximum retries have not been reached, the method proceeds to the next iteration after a delay.
4. Delay Between Retries