better logging for ports and versions (#3048) (#3069)

UnitySDK/Assets/ML-Agents/Scripts/Academy.cs

     public abstract class Academy : MonoBehaviour
     {
         const string k_ApiVersion = "API-12";
+        const int k_EditorTrainingPort = 5004;
 
         /// Temporary storage for global gravity value
         /// Used to restore oringal value when deriving Academy modifies it
         }
 
         // Used to read Python-provided environment parameters
-        static int ReadArgs()
+        static int ReadPortFromArgs()
         {
             var args = System.Environment.GetCommandLineArgs();
             var inputPort = "";
                 }
             }
 
-            return int.Parse(inputPort);
+            try
+            {
+                return int.Parse(inputPort);
+            }
+            catch
+            {
+                // No arg passed, or malformed port number.
+#if UNITY_EDITOR
+                // Try connecting on the default editor port
+                return k_EditorTrainingPort;
+#else
+                // This is an executable, so we don't try to connect.
+                return -1;
+#endif
+            }
+
         }
 
         /// <summary>
             InitializeAcademy();
 
             // Try to launch the communicator by using the arguments passed at launch
-            try
+            var port = ReadPortFromArgs();
+            if (port > 0)
-                        port = ReadArgs()
-                    });
-            }
-            catch
-            {
-#if UNITY_EDITOR
-                Communicator = new RpcCommunicator(
-                    new CommunicatorInitParameters
-                    {
-                        port = 5004
-                    });
-#endif
+                        port = port
+                    }
+                );
             }
 
             if (Communicator != null)
                 }
                 catch
                 {
+                    Debug.Log($"" +
+                        $"Couldn't connect to trainer on port {port} using API version {k_ApiVersion}. " +
+                        "Will perform inference instead."
+                    );
                     Communicator = null;
                 }
 

ml-agents-envs/mlagents/envs/environment.py

             self.executable_launcher(file_name, docker_training, no_graphics, args)
         else:
             logger.info(
-                "Start training by pressing the Play button in the Unity Editor."
+                f"Listening on port {self.port}. "
+                f"Start training by pressing the Play button in the Unity Editor."
             )
         self._loaded = True
 
         if self._unity_version != self._version_:
             self._close()
             raise UnityEnvironmentException(
-                "The API number is not compatible between Unity and python. Python API : {0}, Unity API : "
-                "{1}.\nPlease go to https://github.com/Unity-Technologies/ml-agents to download the latest version "
-                "of ML-Agents.".format(self._version_, self._unity_version)
+                f"The API number is not compatible between Unity and python. "
+                f"Python API: {self._version_}, Unity API: {self._unity_version}.\n"
+                f"Please go to https://github.com/Unity-Technologies/ml-agents/releases/tag/latest_release"
+                f"to download the latest version of ML-Agents."
             )
         self._n_agents: Dict[str, int] = {}
         self._is_first_message = True

ml-agents/mlagents/trainers/learn.py

 
 
 def get_version_string() -> str:
-    return f""" Version information:\n
-    ml-agents: {mlagents.trainers.__version__},
-    ml-agents-envs: {mlagents.envs.__version__},
-    Communicator API: {UnityEnvironment.API_VERSION},
-    TensorFlow: {tf_utils.tf.__version__}
-"""
+    return f""" Version information:
+  ml-agents: {mlagents.trainers.__version__},
+  ml-agents-envs: {mlagents.envs.__version__},
+  Communicator API: {UnityEnvironment.API_VERSION},
+  TensorFlow: {tf_utils.tf.__version__}"""
 
 
 def parse_command_line(argv: Optional[List[str]] = None) -> CommandLineOptions:
         "--cpu", default=False, action="store_true", help="Run with CPU only"
     )
 
-    parser.add_argument("--version", action="version", version=get_version_string())
+    parser.add_argument("--version", action="version", version="")
 
     args = parser.parse_args(argv)
     return CommandLineOptions.from_argparse(args)
         )
     except Exception:
         print("\n\n\tUnity Technologies\n")
+    print(get_version_string())
     options = parse_command_line()
     trainer_logger = logging.getLogger("mlagents.trainers")
     env_logger = logging.getLogger("mlagents.envs")