ROS Connection success event

rosenm15 · September 22, 2021, 11:09am

Is there a way to check an event with the ROSConnection to confirm that an established connection has been created?

I am looking for the event to account for errors where:

No data available on network stream after 10 attempts.

Or when

No connection could be made because the target machine actively refused it?

What should I look for as an event to confirm when a stable connection has been made?

LaurieUnity · September 22, 2021, 5:16pm

You could check the property ROSConnection.HasConnectionError: it will be true until until a message has been received. (ROS_TCP_Endpoint always sends an empty message as soon as a connection is established, to confirm the connection is working.)
This logic is used by the hud to show red arrows.

rosenm15 · September 22, 2021, 6:40pm

@LaurieUnity , What version of ROS_TCP_ENDPOINT is this available in? I am currently on 0.1.2-preview

LaurieUnity · September 22, 2021, 11:10pm

This is a feature of the ROS-TCP-Connector, not the endpoint. It’s present in the current main branch, version 0.5.0. I suggest you update, there have been a lot of performance and reliability improvements since January.

github.com

Unity-Technologies/ROS-TCP-Connector/blob/f7f669f212423ff03817a2094f489547158a3852/com.unity.robotics.ros-tcp-connector/Runtime/TcpConnector/ROSConnection.cs#L76


      
          // GUI window variables
          internal HUDPanel m_HudPanel = null;
          
          ConcurrentQueue<List<byte[]>> m_OutgoingMessages = new ConcurrentQueue<List<byte[]>>();
          ConcurrentQueue<Tuple<string, byte[]>> m_IncomingMessages = new ConcurrentQueue<Tuple<string, byte[]>>();
          CancellationTokenSource m_ConnectionThreadCancellation;
          
          public bool HasConnectionThread => m_ConnectionThreadCancellation != null;
          
          static bool m_HasConnectionError = false;
          public bool HasConnectionError => m_HasConnectionError;
          
          static float s_RealTimeSinceStartup = 0.0f;// only the main thread can access Time.realTimeSinceStartup, so make a copy here
          
          readonly object m_ServiceRequestLock = new object();
          int m_NextSrvID = 101;
          Dictionary<int, TaskPauser> m_ServicesWaiting = new Dictionary<int, TaskPauser>();
          
          struct SubscriberCallback
          {
              public Func<MessageDeserializer, Message> deserialize;

rosenm15 · September 27, 2021, 7:34pm

Thanks, I updated and resolved it with that method.

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ROS Connection success event

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