Socket probe transport doesn't accept / handle incoming connections

[Aaronontheweb]

Given how this is implemented:

akkadotnet-healthcheck/src/Akka.HealthCheck/Transports/Sockets/SocketStatusTransport.cs

Lines 35 to 37 in 85ef553

	_socket = new Socket(SocketType.Stream, ProtocolType.Tcp);
	_socket.Bind(new IPEndPoint(IPAddress.IPv6Any, Settings.Port));
	_socket.Listen(10);

We never actually handle the incoming socket requests, thus the liveness probe will eventually fail given enough time. Need to actually handle the socket request and verify it by sending back some trivial piece of data.

Can you make this fix and verify it via a TCP integration test @izavala ?

[izavala]

Currently the issue that we are seeing with the current setup is:

• Sockets are being opened and we are binding to them, but we are not accepting the connection.
• This will hold the resource and will cause the sockets to timeout and close.
• Once a connection is made, we are not acknowledging that we have handled the connection request.

How to resolve the issue:

• Will implement Akka.io to bind to the Tcp port.
• Once we receive a Tcp.connected message we will respond with a small message.
• After sending the message we will want to close the connection and get back to the listening state.

[izavala]

It looks like using Akka.io may complicate this process as SocketStatusTransport is not an actor and we will not be able to pass it through as an ActorRef.

Using the AccpetAsync socket function and handling these request through Tasks may be an easier implementation.

[izavala]

From looking at the implementation of LivenessTransportActor, it waits for the SocketStatusTransport to open the connection and respond with a TransporWriteStatus(True) message if no exceptions are encountered.

After we have an initial bind with the socket, we would then create a temporary connection to echo the message back and close it immediately after to accept queued connections.

Adding
var handler = await _socket.AcceptAsync();
byte[] msg = Encoding.ASCII.GetBytes("Live");
handler.Send(msg);
handler.Shutdown(SocketShutdown.Both);
handler.Close();

between the if statement and the exception would allow the connection request to come through and close once it has been acknowledged?

https://github.com/izavala/akkadotnet-healthcheck/blob/85ef553f8ef5c98f1dee3a081003c75668ce93da/src/Akka.HealthCheck/Transports/Sockets/SocketStatusTransport.cs#L33-L40

[Aaronontheweb]

closed via #25