Use SemVer to check communication compatibility between C# and Python

com.unity.ml-agents/CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
  - Added ability to start training (initialize model weights) from a previous run ID. (#3710)
  - The internal event `Academy.AgentSetStatus` was renamed to `Academy.AgentPreStep` and made public.
  - The offset logic was removed from DecisionRequester.
+ - The communication API version has been bumped up to 1.0.0 and will use [Semantic Versioning](https://semver.org/) to do compatibility checks for communication between Unity and the Python process.
 
 ### Minor Changes
  - Format of console output has changed slightly and now matches the name of the model/summary directory. (#3630, #3616)

com.unity.ml-agents/Runtime/Academy.cs

@@ -58,7 +58,7 @@ public class Academy : IDisposable
         /// on each side, although we may allow some flexibility in the future.
         /// This should be incremented whenever a change is made to the communication protocol.
         /// </summary>
-        const string k_ApiVersion = "0.16.0";
+        const string k_ApiVersion = "1.0.0";
 
         /// <summary>
         /// Unity package version of com.unity.ml-agents.

com.unity.ml-agents/Runtime/Communicator/RpcCommunicator.cs

@@ -61,6 +61,13 @@ public RpcCommunicator(CommunicatorInitParameters communicatorInitParameters)
 
         #region Initialization
 
+        internal static bool CheckCommunicationVersionsAreCompatible(string unityCommunicationVersion, string pythonApiVersion)
+        {
+            var unityVersion = new Version(unityCommunicationVersion);
+            var pythonVersion = new Version(pythonApiVersion);
+            return unityVersion.Major == pythonVersion.Major;
+        }
+
         /// <summary>
         /// Sends the initialization parameters through the Communicator.
         /// Is used by the academy to send initialization parameters to the communicator.
@@ -93,11 +100,12 @@ public UnityRLInitParameters Initialize(CommunicatorInitParameters initParameter
                 {
                     var pythonCommunicationVersion = initializationInput.RlInitializationInput.CommunicationVersion;
                     var pythonPackageVersion = initializationInput.RlInitializationInput.PackageVersion;
-                    if (pythonCommunicationVersion != initParameters.unityCommunicationVersion)
+                    var unityCommunicationVersion = initParameters.unityCommunicationVersion;
+                    if (!CheckCommunicationVersionsAreCompatible(unityCommunicationVersion, pythonCommunicationVersion))
                     {
                         Debug.LogWarningFormat(
-                            "Communication protocol between python ({0}) and Unity ({1}) don't match. " +
-                            "Python library version: {2}.",
+                            "Communication protocol between python ({0}) and Unity ({1}) have different " +
+                            "major versions and are incompatible. Python library version: {2}.",
                             pythonCommunicationVersion, initParameters.unityCommunicationVersion,
                             pythonPackageVersion
                         );

com.unity.ml-agents/Tests/Editor/Communicator/RpcCommunicatorTests.cs

@@ -0,0 +1,18 @@
+using NUnit.Framework;
+
+namespace MLAgents.Tests.Communicator
+{
+    [TestFixture]
+    public class RpcCommunicatorTests
+    {
+        [Test]
+        public void TestCheckCommunicationVersionsAreCompatible()
+        {
+            var unityVerStr = "1.0.0";
+            var pythonVerStr = "1.0.0";
+            Assert.IsTrue(RpcCommunicator.CheckCommunicationVersionsAreCompatible(unityVerStr, pythonVerStr));
+            unityVerStr = "2.0.0";
+            Assert.IsFalse(RpcCommunicator.CheckCommunicationVersionsAreCompatible(unityVerStr, pythonVerStr));
+        }
+    }
+}

ml-agents-envs/mlagents_envs/environment.py

@@ -1,4 +1,5 @@
 import atexit
+from distutils.version import StrictVersion
 import glob
 import uuid
 import numpy as np
@@ -58,7 +59,7 @@ class UnityEnvironment(BaseEnv):
     # Currently we require strict equality between the communication protocol
     # on each side, although we may allow some flexibility in the future.
     # This should be incremented whenever a change is made to the communication protocol.
-    API_VERSION = "0.16.0"
+    API_VERSION = "1.0.0"
 
     # Default port that the editor listens on. If an environment executable
     # isn't specified, this port will be used.
@@ -153,12 +154,13 @@ def __init__(
             self._close(0)
             raise
 
-        unity_communicator_version = aca_params.communication_version
-        if unity_communicator_version != UnityEnvironment.API_VERSION:
+        unity_communicator_version = StrictVersion(aca_params.communication_version)
+        api_version = StrictVersion(UnityEnvironment.API_VERSION)
+        if unity_communicator_version.version[0] != api_version.version[0]:
             self._close(0)
             raise UnityEnvironmentException(
                 f"The communication API version is not compatible between Unity and python. "
-                f"Python API: {UnityEnvironment.API_VERSION}, Unity API: {unity_communicator_version}.\n "
+                f"Python API: {UnityEnvironment.API_VERSION}, Unity API: {aca_params.communication_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."
             )