Amqp Connector don't work with RestartSource

[Adriano Santos]

HI guys!
I am trying to create a Reconnectable Source with RestartSource using Akka Streams Amqp.V1 and some strange things happen. When I disconnect the network, RestartSource does not try to reconnect again and no message is printed in the logs. However, when I receive an invalid message (type incompatible) it restarts my source. I am not sure why this is so and I would like to know if you have already been there and if you could help me. Below is the Source creation code:

using System.Numerics;
using Akka.Serialization;
using Akka.Streams.Amqp.V1.Dsl;
using Akka.Streams.Dsl;
using Amqp;
using System;
using Akka.Actor;
using Address = Amqp.Address;
using Akka.Streams;
using Akka.Streams.Amqp.V1;
using System.Text;

namespace image_processor_akkanet
{
    class Program
    {
        private static Connection connection;
        private static Session session;

        static void Main(string[] args)
        {
            var sys = ActorSystem.Create("AMQP-System");
            var materializer = ActorMaterializer.Create(sys);
            var serialization = sys.Serialization;
            var serializer = serialization.FindSerializerForType(typeof(byte[]));

            try
            {
                var address = new Address("0.0.0.0", 61616, "admin", "admin", scheme: "AMQP");
                connection = new Connection(address);
                session = new Session(connection);

                var queueName = "akka.teste";
                var receiverlinkName = "amqp-conn-test-sender";

                //create source
                var amqpSource = RestartSource.OnFailuresWithBackoff(
                    () => {
                        Console.WriteLine("Start/Restart...");
                        return AmqpSource
                          .Create(new NamedQueueSourceSettings<byte[]>(session, receiverlinkName, queueName, 200, serializer));
                    },
                    TimeSpan.FromSeconds(1),
                    TimeSpan.FromSeconds(3),
                    0.2,
                    Int16.MaxValue
                );

                //run source
                var result = amqpSource
                    .Throttle(1, TimeSpan.FromSeconds(1), 10, ThrottleMode.Shaping)
                    .Select(elem => Encoding.UTF8.GetString(elem, 0, elem.Length))
                    .RunForeach(elem => Console.WriteLine(elem), materializer);

                result.Wait(TimeSpan.FromSeconds(Int16.MaxValue));
            }
            catch (Exception ex)
            {
                Console.WriteLine("Error " + ex.Message);
            }
            finally
            {
                session.Close();
                connection.Close();
            }
        }
    }
}

I tried using both RestartSource.OnFailuresWithBackoff and RestartSource.WithBackoff both to no avail

My project and dependencies:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <RootNamespace>image_processor_akkanet</RootNamespace>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Akka" Version="1.4.11" />
    <PackageReference Include="Akka.Streams" Version="1.4.11" />
    <PackageReference Include="Akka.Streams.Amqp.V1" Version="1.0.0-beta2" />
  </ItemGroup>

</Project>

I'm using ActiveMQ Artemis as a AMQP Broker.

[Adriano Santos]

Ping

[Gregorius Soedharmo]

This is actually by design. because the Source object does not have any reference to the AMQP Connection object, it does not have a direct way of reconnecting with the server.
Try moving the Connection and Session initialization into the source factory Func in the RestartSource.OnFailuresWithBackoff method argument.

[Gregorius Soedharmo]

I might be mistaken, there might be some problem with the way connections were made inside the connector that prevents retry

[Gregorius Soedharmo]

The PR should address the problem. I've included examples on how to make both Sink and Source resistant to transient connection problems.

[Adriano Santos]

Hi @Arkatufus Can you tell me when we will have a version with this correction published via nuget?

[Gregorius Soedharmo]

As soon as someone reviewed the changes and approved it.

[Adriano Santos]

@Aaronontheweb can you take a look at this? I look forward to putting the first software made using Akka.Net in my company and that is a deterrent

[Aaron Stannard]

I'm reviewing it now

[Adriano Santos]

Thanks @Aaronontheweb

[Aaron Stannard]

@sleipnir this is now live on NuGet as Alpakka v1.0.0-beta3 https://github.com/akkadotnet/Alpakka/releases/tag/1.0.0-beta3

[Adriano Santos]

Awesome work guys! Thank you @Aaronontheweb and @Arkatufus