why error message "Operation failed after 3 times" appears even there is no re-try for err-CodePudding

I want to re-try execution of code block if error code = 100 and if all re-try fails I want to print the message "Operation failed after 3 times" for this case only.

I have below Polly policy defined,

var retryPolicy = Policy
            .Handle<Exception>(ex =>
            {
                var errorMessage = ex.InnerException?.Message;
                if (errorMessage == null) return false;
                try
                {
                    dynamic error = JsonConvert.DeserializeObject(errorMessage);
                    if (error != null && error.errorCode == 100)
                    {
                        Console.WriteLine("Try to run again...");
                        return true;
                    }

                    Console.WriteLine("Error occurred: "   ex.Message);
                    return false;
                }
                catch (Exception)
                {
                    Console.WriteLine("Exception Error occurred: "   ex.Message);
                    return false;
                }
            })
            .WaitAndRetryAsync(2, _ => TimeSpan.FromSeconds(10));

And below is the code for policy execution,

 try
        {
            var myClass = new MyClass();
            await retryPolicy.ExecuteAsync(async () => await myClass.Get());
        }
        catch (Exception)
        {
            Console.WriteLine("Operation failed after 3 times");
        }

For below code everything perfect and I am getting desired result as well,

Try to run again...
Try to run again...
Try to run again...
Operation failed after 3 times

public async Task Get()
    {
        await Task.Delay(1);
        throw new Exception("message", new Exception("{\"message\":\"inner exception\",\"errorCode\":\"100\"}"));
    }

But when I am execution below code ( no error code = 100), then my re-try not happening but the message "Operation failed after 3 times" is also printing in console. What's the reason for it and how to avoid it?

Exception Error occurred: message
Operation failed after 3 times

public async Task Get()
    {
        await Task.Delay(1);
        throw new Exception("message", new Exception("hey you"));
    }

CodePudding user response：

In general it's not good, to have a try-catch-block in an Exception handling. In your case it's generated because of your JsonConvert, but do you really need that?

I would suggest, to throw an Exception of type Win32Exception, because here you can define an error code. Like this

throw new Exception("message", new System.ComponentModel.Win32Exception(100));

With that you don't need to do a Json-Deserialzation and you got no "second" try-catch-block.

"Operation failed after 3 times" is printed on every exception, says also on exceptions without an inner one or error code == 100. To fix that, you can now do something like

try
{
    var myClass = new MyClass();
    await retryPolicy.ExecuteAsync(async () => await myClass.Get());
}
catch (Exception ex) 
{
    bool innerIsWin32 = ex.InnerException is System.ComponentModel.Win32Exception;
    if (innerIsWin32)
    {
        var w32ex = (Win32Exception)ex.InnerException
        if (w32ex.ErrorCode == 100)
        {
            Console.WriteLine("Operation failed after 3 times");
        }
    }
}

Starting with C# 6, when can be used in a catch statement to specify a condition that must be true for the handler for a specific exception to execute.

catch (Win32Exception ex) when (ex.InnerException is Win32Exception) {
    var w32ex = (Win32Exception)ex.InnerException;
    var code =  w32ex.ErrorCode;
    if (code == 100)
    {
         Console.WriteLine("Operation failed after 3 times");
    }
}