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lifeemotions / knx.net

KNX.net provides a KNX API for .NET
MIT License
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Threads stuck open after connection fail #59

Open FalcoGer opened 4 years ago

FalcoGer commented 4 years ago

I made a shell script to launch my program in a loop in case my programm exits for any reason. While rare, the programm occasionally encounters a situation in which it has to reset. One of those situations is when it fails to connect to the KNX-Tunneling interface 10 times in a row. Then I decide to just restart the program and have everything in a known state.

Just today I had checked in on my project and found the service running, but no data being logged for 5 days. Examining the journal I found this:

Jul 18 20:04:27 logger-pi KNX_Logger.sh[13144]: [E-KNX] 18.07.2019 20: 04:27.113: ID: KNXLib.KnxReceiverTunnelingMSG: A connection attempt failed because the connected party did not properly respondafter a period of time, or established connection failed because connected host has failed to respond
Jul 18 20:04:27 logger-pi KNX_Logger.sh[13144]: No knx-connection during main loop. Attempted reconnects so far: 10
Jul 18 20:04:27 logger-pi KNX_Logger.sh[13144]: [E-KNX] 18.07.2019 20: 04:27.223: ID: KNXLib.KnxReceiverTunnelingMSG: System.Net.Sockets.SocketException (0x80004005): A connection attempt failed because the connected party did not properly respondafter a period of time, or established connection failed because connected host has failed to respond
Jul 18 20:04:27 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom_nochecks_exc (System.Byte[] buf, System.Int32 offset, System.Int32 size, System.Net.Sockets.SocketFlags flags, System.Net.EndPoint& remote_end, System.Boolean throwOnError, System.Int32& error) [0x00076] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:27 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Int32 offset, System.Int32 size, System.Net.Sockets.SocketFlags socketFlags, System.Net.EndPoint& remoteEP) [0x00029] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:27 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Net.EndPoint& remoteEP) [0x0000d] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:27 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.UdpClient.Receive (System.Net.IPEndPoint& remoteEP) [0x00014] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:27 logger-pi KNX_Logger.sh[13144]:   at KNXLib.KnxReceiverTunneling.ReceiverThreadFlow () [0x00000] in <Path>\KnxLogger\knx.net\src\KNXLib\KnxReceiverTunneling.cs:42
Jul 18 20:04:27 logger-pi KNX_Logger.sh[13144]: [E-KNX] 18.07.2019 20: 04:27.226: ID: KNXLib.KnxReceiverTunnelingMSG:   at System.Net.Sockets.Socket.ReceiveFrom_nochecks_exc (System.Byte[] buf, System.Int32 offset, System.Int32 size, System.Net.Sockets.SocketFlags flags, System.Net.EndPoint& remote_end, System.Boolean throwOnError, System.Int32& error) [0x00076] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:27 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Int32 offset, System.Int32 size, System.Net.Sockets.SocketFlags socketFlags, System.Net.EndPoint& remoteEP) [0x00029] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:27 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Net.EndPoint& remoteEP) [0x0000d] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:27 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.UdpClient.Receive (System.Net.IPEndPoint& remoteEP) [0x00014] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:27 logger-pi KNX_Logger.sh[13144]:   at KNXLib.KnxReceiverTunneling.ReceiverThreadFlow () [0x00000] in <Path>\KnxLogger\knx.net\src\KNXLib\KnxReceiverTunneling.cs:42
Jul 18 20:04:27 logger-pi KNX_Logger.sh[13144]: [DELEGATE] Disconnected.
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: 6/0/80 received data from 7.1.11 but it is not tracked.
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: Data: 0x33 0x14                (00110011 00010100)
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: [E-KNX] 18.07.2019 20: 04:32.219: ID: KNXLib.KnxReceiverTunnelingMSG: A connection attempt failed because the connected party did not properly respondafter a period of time, or established connection failed because connected host has failed to respond
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: [E-KNX] 18.07.2019 20: 04:32.226: ID: KNXLib.KnxReceiverTunnelingMSG: System.Net.Sockets.SocketException (0x80004005): A connection attempt failed because the connected party did not properly respondafter a period of time, or established connection failed because connected host has failed to respond
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom_nochecks_exc (System.Byte[] buf, System.Int32 offset, System.Int32 size, System.Net.Sockets.SocketFlags flags, System.Net.EndPoint& remote_end, System.Boolean throwOnError, System.Int32& error) [0x00076] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Int32 offset, System.Int32 size, System.Net.Sockets.SocketFlags socketFlags, System.Net.EndPoint& remoteEP) [0x00029] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Net.EndPoint& remoteEP) [0x0000d] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.UdpClient.Receive (System.Net.IPEndPoint& remoteEP) [0x00014] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at KNXLib.KnxReceiverTunneling.ReceiverThreadFlow () [0x00000] in <Path>\KnxLogger\knx.net\src\KNXLib\KnxReceiverTunneling.cs:42
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: [E-KNX] 18.07.2019 20: 04:32.228: ID: KNXLib.KnxReceiverTunnelingMSG:   at System.Net.Sockets.Socket.ReceiveFrom_nochecks_exc (System.Byte[] buf, System.Int32 offset, System.Int32 size, System.Net.Sockets.SocketFlags flags, System.Net.EndPoint& remote_end, System.Boolean throwOnError, System.Int32& error) [0x00076] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Int32 offset, System.Int32 size, System.Net.Sockets.SocketFlags socketFlags, System.Net.EndPoint& remoteEP) [0x00029] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Net.EndPoint& remoteEP) [0x0000d] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.UdpClient.Receive (System.Net.IPEndPoint& remoteEP) [0x00014] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at KNXLib.KnxReceiverTunneling.ReceiverThreadFlow () [0x00000] in <Path>\KnxLogger\knx.net\src\KNXLib\KnxReceiverTunneling.cs:42
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: [DELEGATE] Disconnected.
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: ================================================================================
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: EXCEPTION
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: Exception time: 18.07.2019 20:04:32.608
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: Exception message: Reconnect failed 11 times in a row.
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: Exception source: KNX_Logger
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: Data:
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: Help link:
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: ================================================================================
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: Stack Trace:
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at KNX_Logger.KNX_Logger.Main (System.String[] args) [0x00574] in <Path>\KnxLogger\KNX_Logger\KNX_Logger.cs:299
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: ================================================================================
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: Disconnecting normally.
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: Shutdown complete. Exiting.
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: [E-KNX] 18.07.2019 20: 04:32.738: ID: KNXLib.KnxReceiverTunnelingMSG: A connection attempt failed because the connected party did not properly respondafter a period of time, or established connection failed because connected host has failed to respond
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: [E-KNX] 18.07.2019 20: 04:32.754: ID: KNXLib.KnxReceiverTunnelingMSG: System.Net.Sockets.SocketException (0x80004005): A connection attempt failed because the connected party did not properly respondafter a period of time, or established connection failed because connected host has failed to respond
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom_nochecks_exc (System.Byte[] buf, System.Int32 offset, System.Int32 size, System.Net.Sockets.SocketFlags flags, System.Net.EndPoint& remote_end, System.Boolean throwOnError, System.Int32& error) [0x00076] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Int32 offset, System.Int32 size, System.Net.Sockets.SocketFlags socketFlags, System.Net.EndPoint& remoteEP) [0x00029] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Net.EndPoint& remoteEP) [0x0000d] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.UdpClient.Receive (System.Net.IPEndPoint& remoteEP) [0x00014] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at KNXLib.KnxReceiverTunneling.ReceiverThreadFlow () [0x00000] in <Path>\KnxLogger\knx.net\src\KNXLib\KnxReceiverTunneling.cs:42
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]: [E-KNX] 18.07.2019 20: 04:32.759: ID: KNXLib.KnxReceiverTunnelingMSG:   at System.Net.Sockets.Socket.ReceiveFrom_nochecks_exc (System.Byte[] buf, System.Int32 offset, System.Int32 size, System.Net.Sockets.SocketFlags flags, System.Net.EndPoint& remote_end, System.Boolean throwOnError, System.Int32& error) [0x00076] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Int32 offset, System.Int32 size, System.Net.Sockets.SocketFlags socketFlags, System.Net.EndPoint& remoteEP) [0x00029] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Net.EndPoint& remoteEP) [0x0000d] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.UdpClient.Receive (System.Net.IPEndPoint& remoteEP) [0x00014] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at KNXLib.KnxReceiverTunneling.ReceiverThreadFlow () [0x00000] in <Path>\KnxLogger\knx.net\src\KNXLib\KnxReceiverTunneling.cs:42

After which I restarted...

Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Net.EndPoint& remoteEP) [0x0000d] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.UdpClient.Receive (System.Net.IPEndPoint& remoteEP) [0x00014] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:04:32 logger-pi KNX_Logger.sh[13144]:   at KNXLib.KnxReceiverTunneling.ReceiverThreadFlow () [0x00000] in <Path>\KnxLogger\knx.net\src\KNXLib\KnxReceiverTunneling.cs:42
Jul 24 13:29:45 logger-pi systemd[1]: Stopping Service logging data from KNX IP-Interface...
Jul 24 13:29:45 logger-pi systemd[1]: Stopped Service logging data from KNX IP-Interface.
Jul 24 13:29:45 logger-pi systemd[1]: Started Service logging data from KNX IP-Interface.
Jul 24 13:29:45 logger-pi KNX_Logger.sh[27799]: [I]Working Directory: <Path>/KNX_Logger/bin
Jul 24 13:29:45 logger-pi KNX_Logger.sh[27799]: [I]Starting KNX_Logger shell loop script

There are some issues here that I don't fully understand:

The most pressing issue is that the shell script output that runs the program in a loop never triggered, meaning the shell script hung on the program launch. and systemd told me the program was running.
I suspect some thread was at work here and didn't quit properly when the main programm returned from execution, letting the program "hang" in a state where it should've exited.

Could you please look into this and please mark all threads as IsBackground = true.

The code I use for quitting is this:

Main:

try
{
    while(true) // not exactly, but practically it is. it's not supposed to stop.
    {
        // do logging and other things
    }
}
catch (Exception e)
{
    Helper.PrintException(e);
}
finally
{
    if (knx != null)
    {
        Console.WriteLine("Disconnecting normally.");
        // remove disconnect handler so it doesn't try to reconnect
        knx.DisconnectForGood();
    }
     Console.WriteLine("Shutdown complete. Exiting.");
}
return 0;

KNX

/// <summary>
/// Disconnect, will not attempt reconnect. connection is set null
/// </summary>
public void DisconnectForGood()
{
    conn.KnxDisconnectedDelegate -= Disconnected;
    conn.Disconnect();
    // clean up
    conn = null;
}

My shell script:

#!/bin/sh
cd <Path>/KNX_Logger/bin
echo [I]Working Directory: $(pwd)
echo [I]Starting KNX_Logger shell loop script
sleep 2
echo [I]Converting debug information for mono
for f in *.pdb
do
  if [ -r "${f%.pdb}.dll" ]
  then
    echo "[I]${f%.pdb}.dll"
    pdb2mdb "${f%.pdb}.dll"
  else
    if [ -r "${f%.pdb}.exe" ]
        then
          echo "[I]${f%.pdb}.exe"
          pdb2mdb "${f%.pdb}.exe"
        else
        echo "[W]${f%.pdb} has no corresponding dll or exe. Ignoring."
        fi
  fi
done
echo [I]Done converting.
sleep 2
echo [I]Entering loop
while (true)
do
    sleep 10
    echo -n "Started " >> <Path>/KNX_Logger/log/startLog.log
    date >> <Path>/KNX_Logger/log/startLog.log
        echo starting KNX_Logger.exe
    mono --debug <Path>/KNX_Logger/bin/KNX_Logger.exe
    echo -n "Stopped " >> <Path>/KNX_Logger/log/startLog.log
    date >> <Path>/KNX_Logger/log/startLog.log
done

"Stopped" was never written to startLog

FalcoGer commented 4 years ago

Upon further examining the log I found this bit

Jul 18 20:02:22 logger-pi KNX_Logger.sh[13144]: 6/0/82 received data from 7.1.11 but it is not tracked.
Jul 18 20:02:22 logger-pi KNX_Logger.sh[13144]: Data: 0x2B 0x34 0x18 0x41                (00101011 00110100 00011000 01000001)
Jul 18 20:02:24 logger-pi KNX_Logger.sh[13144]: 6/0/80 received data from 7.1.11 but it is not tracked.
Jul 18 20:02:24 logger-pi KNX_Logger.sh[13144]: Data: 0x2C 0x14                (00101100 00010100)
Jul 18 20:02:31 logger-pi KNX_Logger.sh[13144]: [DELEGATE] Disconnected.
Jul 18 20:02:42 logger-pi KNX_Logger.sh[13144]: No knx-connection during main loop. Attempted reconnects so far: 0
Jul 18 20:02:46 logger-pi KNX_Logger.sh[13144]: [DELEGATE] Connected to KNX.
Jul 18 20:02:46 logger-pi KNX_Logger.sh[13144]: No knx-connection during main loop. Attempted reconnects so far: 1
Jul 18 20:02:51 logger-pi KNX_Logger.sh[13144]: 6/0/81 received data from 7.1.11 but it is not tracked.
Jul 18 20:02:51 logger-pi KNX_Logger.sh[13144]: Data: 0xE4 0xE0 0x00 0x41                (11100100 11100000 00000000 01000001)
Jul 18 20:02:51 logger-pi KNX_Logger.sh[13144]: [E-KNX] 18.07.2019 20: 02:51.832: ID: KNXLib.KnxReceiverTunnelingMSG: A connection attempt failed because the connected party did not properly respondafter a period of time, or established connection failed because connected host has failed to respond
Jul 18 20:02:52 logger-pi KNX_Logger.sh[13144]: 6/0/82 received data from 7.1.11 but it is not tracked.
Jul 18 20:02:52 logger-pi KNX_Logger.sh[13144]: Data: 0x2B 0x34 0x18 0x41                (00101011 00110100 00011000 01000001)
Jul 18 20:02:52 logger-pi KNX_Logger.sh[13144]: [E-KNX] 18.07.2019 20: 02:52.062: ID: KNXLib.KnxReceiverTunnelingMSG: System.Net.Sockets.SocketException (0x80004005): A connection attempt failed because the connected party did not properly respondafter a period of time, or established connection failed because connected h
Jul 18 20:02:52 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom_nochecks_exc (System.Byte[] buf, System.Int32 offset, System.Int32 size, System.Net.Sockets.SocketFlags flags, System.Net.EndPoint& remote_end, System.Boolean throwOnError, System.Int32& error) [0x00076] in <bd46d4d4f7964dfa9beea098
Jul 18 20:02:52 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Int32 offset, System.Int32 size, System.Net.Sockets.SocketFlags socketFlags, System.Net.EndPoint& remoteEP) [0x00029] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:02:52 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Net.EndPoint& remoteEP) [0x0000d] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:02:52 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.UdpClient.Receive (System.Net.IPEndPoint& remoteEP) [0x00014] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:02:52 logger-pi KNX_Logger.sh[13144]:   at KNXLib.KnxReceiverTunneling.ReceiverThreadFlow () [0x00000] in <Path>\KnxLogger\knx.net\src\KNXLib\KnxReceiverTunneling.cs:42
Jul 18 20:02:52 logger-pi KNX_Logger.sh[13144]: [E-KNX] 18.07.2019 20: 02:52.064: ID: KNXLib.KnxReceiverTunnelingMSG:   at System.Net.Sockets.Socket.ReceiveFrom_nochecks_exc (System.Byte[] buf, System.Int32 offset, System.Int32 size, System.Net.Sockets.SocketFlags flags, System.Net.EndPoint& remote_end, System.Boolean thr
Jul 18 20:02:52 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Int32 offset, System.Int32 size, System.Net.Sockets.SocketFlags socketFlags, System.Net.EndPoint& remoteEP) [0x00029] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:02:52 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.Socket.ReceiveFrom (System.Byte[] buffer, System.Net.EndPoint& remoteEP) [0x0000d] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:02:52 logger-pi KNX_Logger.sh[13144]:   at System.Net.Sockets.UdpClient.Receive (System.Net.IPEndPoint& remoteEP) [0x00014] in <bd46d4d4f7964dfa9beea098499ab597>:0
Jul 18 20:02:52 logger-pi KNX_Logger.sh[13144]:   at KNXLib.KnxReceiverTunneling.ReceiverThreadFlow () [0x00000] in <Path>\KnxLogger\knx.net\src\KNXLib\KnxReceiverTunneling.cs:42
Jul 18 20:02:52 logger-pi KNX_Logger.sh[13144]: [DELEGATE] Disconnected.

Which seems to be the start of all of that trouble. In my KNX-Class I set a boolean variable false whenever the Disconnected Delegate is called, and true whenever the Connected Delegate is called. I use that to decide if I want to call the connect function in the main loop using this bit of code.

if (knx.ConnectedState == false)
{
    Console.WriteLine("No knx-connection during main loop. Attempted reconnects so far: " + reconnectAttempts.ToString());
    // this is 5 seconds
    Thread.Sleep(RECONNECT_DELAY); // sleep for a bit to prevent spamming while attempting reconnecting
    knx.Connect();
    reconnectAttempts++;
    if (reconnectAttempts > MAX_RECONNECT_ATTEMPTS)
    {
        throw new Exception("Reconnect failed " + reconnectAttempts.ToString() + " times in a row.");
    }
}
else
{
    reconnectAttempts = 0;
}

For some reason the disconnect delegate was called, the variable was set false. But then when reconnecting it didn't set the variable in the connected delegate? Perhaps it happened like so:

  1. disconnect
  2. set variable false in disconnect delegate
  3. first reconnect attempt
  4. connect (after 5 seconds)
  5. check variable, reads false
  6. connected delegate call
  7. set variable true
  8. reconnect attempt (despite being connected)
  9. error
  10. disconnect delegate call (?)
  11. now variable is set false, but connection is up.
  12. connection isn't closed when program exits (?)