What happen if I do not acknowledge?

[realtebo]

I am using your project to implement a queue-supported mail sending system

           $amqp->consume('communication-sent', function ($message, $resolver) use ($mailController) {

                $messageDecoded = json_decode($message->body);

                $communication = $messageDecoded->communication;
                $emailAddress = $messageDecoded->email;

                print('Sending mail to ' . $emailAddress . " [communication]\n");
                try {
                    $mailController->send($emailAddress, new CommunicationSent($communication));
                    print('Sending successful\n');
                    sleep(10);
                }catch (\Exception $e){
                    print("Error: ".$e->getMessage());
                }

                $resolver->acknowledge($message);
                $resolver->stopWhenProcessed();
            });

i would like that the mail to send, in the queue, wil NOT BE lost if sending mail crashes for some reason.

Could I simply move $resolver->acknowledge($message); into the try branch? If I do this, and the code skip to catch branch, will the message in the queue be lost or is this available again and again untile someone reading it will also aknowledge?

[bschmitt]

Yes, only acknowledge when e-mail sending was successful. Please also check how your queue is configured.

[realtebo]

Should I move only

$resolver->acknowledge($message);
$resolver->stopWhenProcessed();

or both ?

$resolver->acknowledge($message);
$resolver->stopWhenProcessed();

What's the difference between the 2?