feat: HeadlessAutoStart and HeadlessFrameLimiter (#318)

* feat: HeadlessAutoStart component

* feat: HeadlessFrameLimiter

* remove from NetMan and misc cleanup of useless virtual OnDestroy

* fix refs and tests

* fix poor comments

* remove useless ifdef and add required using

* fix potential NRE

* add simple tests

* fix smells

Assets/Mirror/Components/HeadlessAutoStart.cs

@@ -0,0 +1,28 @@
+using UnityEngine;
+using UnityEngine.Rendering;
+
+namespace Mirror
+{
+    public class HeadlessAutoStart : MonoBehaviour
+    {
+        public NetworkServer server;
+
+        /// <summary>
+        /// Automatically invoke StartServer()
+        /// <para>If the application is a Server Build or run with the -batchMode ServerRpc line arguement, StartServer is automatically invoked.</para>
+        /// </summary>
+        [Tooltip("Should the server auto-start when the game is started in a headless build?")]
+        public bool startOnHeadless = true;
+
+        void Start()
+        {
+            // headless mode? then start the server
+            // can't do this in Awake because Awake is for initialization.
+            // some transports might not be ready until Start.
+            if (server && SystemInfo.graphicsDeviceType == GraphicsDeviceType.Null && startOnHeadless)
+            {
+                _ = server.ListenAsync();
+            }
+        }
+    }
+}

Assets/Mirror/Components/HeadlessFrameLimiter.cs

@@ -0,0 +1,29 @@
+using UnityEngine;
+using UnityEngine.Rendering;
+
+namespace Mirror
+{
+    public class HeadlessFrameLimiter : MonoBehaviour
+    {
+        static readonly ILogger logger = LogFactory.GetLogger<NetworkManager>();
+
+        /// <summary>
+        /// Server Update frequency, per second. Use around 60Hz for fast paced games like Counter-Strike to minimize latency. Use around 30Hz for games like WoW to minimize computations. Use around 1-10Hz for slow paced games like EVE.
+        /// </summary>
+        [Tooltip("Server Update frequency, per second. Use around 60Hz for fast paced games like Counter-Strike to minimize latency. Use around 30Hz for games like WoW to minimize computations. Use around 1-10Hz for slow paced games like EVE.")]
+        public int serverTickRate = 30;
+
+        /// <summary>
+        /// Set the frame rate for a headless server.
+        /// </summary>
+        public void Start()
+        {
+            // set a fixed tick rate instead of updating as often as possible
+            if (SystemInfo.graphicsDeviceType == GraphicsDeviceType.Null)
+            {
+                Application.targetFrameRate = serverTickRate;
+                if (logger.logEnabled) logger.Log("Server Tick Rate set to: " + Application.targetFrameRate + " Hz.");
+            }
+        }
+    }
+}

Assets/Mirror/Examples/Benchmarks/10k/Scripts/BenchmarkNetworkManager.cs

@@ -15,7 +15,7 @@ public class BenchmarkNetworkManager : NetworkManager
 
         NetworkSceneManager sceneManager;
 
-        public override void Start()
+        public void Start()
         {
             sceneManager = GetComponent<NetworkSceneManager>();
         }

Assets/Mirror/Runtime/INetworkManager.cs

@@ -11,7 +11,5 @@ public interface INetworkManager
         void StopServer();
 
         void StopClient();
-
-        void OnDestroy();
     }
 }

Assets/Mirror/Runtime/NetworkManager.cs

@@ -3,7 +3,6 @@
 using System.Threading.Tasks;
 using UnityEngine;
 using UnityEngine.Events;
-using UnityEngine.Rendering;
 
 namespace Mirror
 {
@@ -17,19 +16,6 @@ public class NetworkManager : MonoBehaviour, INetworkManager
     {
         static readonly ILogger logger = LogFactory.GetLogger<NetworkManager>();
 
-        /// <summary>
-        /// Automatically invoke StartServer()
-        /// <para>If the application is a Server Build or run with the -batchMode ServerRpc line arguement, StartServer is automatically invoked.</para>
-        /// </summary>
-        [Tooltip("Should the server auto-start when the game is started in a headless build?")]
-        public bool startOnHeadless = true;
-
-        /// <summary>
-        /// Server Update frequency, per second. Use around 60Hz for fast paced games like Counter-Strike to minimize latency. Use around 30Hz for games like WoW to minimize computations. Use around 1-10Hz for slow paced games like EVE.
-        /// </summary>
-        [Tooltip("Server Update frequency, per second. Use around 60Hz for fast paced games like Counter-Strike to minimize latency. Use around 30Hz for games like WoW to minimize computations. Use around 1-10Hz for slow paced games like EVE.")]
-        public int serverTickRate = 30;
-
         public NetworkServer server;
         public NetworkClient client;
 
@@ -50,37 +36,11 @@ public class NetworkManager : MonoBehaviour, INetworkManager
         /// </summary>
         public UnityEvent OnStopHost = new UnityEvent();
 
-        #region Unity Callbacks
-
-        /// <summary>
-        /// virtual so that inheriting classes' Start() can call base.Start() too
-        /// </summary>
-        public virtual void Start()
-        {
-            logger.Log("Thank you for using Mirror! https://mirror-networking.com");
-
-            // headless mode? then start the server
-            // can't do this in Awake because Awake is for initialization.
-            // some transports might not be ready until Start.
-            //
-            // (tick rate is applied in StartServer!)
-            if (SystemInfo.graphicsDeviceType == GraphicsDeviceType.Null && startOnHeadless)
-            {
-                _ = StartServer();
-            }
-        }
-
-        #endregion
-
-        #region Start & Stop
-
         // full server setup code, without spawning objects yet
         async Task SetupServer()
         {
             logger.Log("NetworkManager SetupServer");
 
-            ConfigureServerFrameRate();
-
             // start listening to network connections
             await server.ListenAsync();
         }
@@ -167,34 +127,5 @@ public void StopClient()
         {
             client.Disconnect();
         }
-
-        /// <summary>
-        /// Set the frame rate for a headless server.
-        /// <para>Override if you wish to disable the behavior or set your own tick rate.</para>
-        /// </summary>
-        public virtual void ConfigureServerFrameRate()
-        {
-            // set a fixed tick rate instead of updating as often as possible
-            // * if not in Editor (it doesn't work in the Editor)
-            // * if not in Host mode
-#if !UNITY_EDITOR
-            if (!client.Active && SystemInfo.graphicsDeviceType == GraphicsDeviceType.Null)
-            {
-                Application.targetFrameRate = serverTickRate;
-                if (logger.logEnabled) logger.Log("Server Tick Rate set to: " + Application.targetFrameRate + " Hz.");
-            }
-#endif
-        }
-
-        /// <summary>
-        /// virtual so that inheriting classes' OnDestroy() can call base.OnDestroy() too
-        /// </summary>
-        public virtual void OnDestroy()
-        {
-            logger.Log("NetworkManager destroyed");
-        }
-
-        #endregion
-
     }
 }

Assets/Mirror/Tests/Editor/HeadlessAutoStartTest.cs

@@ -0,0 +1,32 @@
+using UnityEngine;
+using NUnit.Framework;
+using Object = UnityEngine.Object;
+
+namespace Mirror.Tests
+{
+    [TestFixture]
+    public class HeadlessAutoStartTest : MonoBehaviour
+    {
+        protected GameObject testGO;
+        protected HeadlessAutoStart comp;
+
+        [SetUp]
+        public void Setup()
+        {
+            testGO = new GameObject();
+            comp = testGO.AddComponent<HeadlessAutoStart>();
+        }
+
+        [TearDown]
+        public void Teardown()
+        {
+            Object.DestroyImmediate(testGO);
+        }
+
+        [Test]
+        public void StartOnHeadlessValue()
+        {
+            Assert.That(comp.startOnHeadless, Is.True);
+        }
+    }
+}

Assets/Mirror/Tests/Editor/HeadlessFrameLimiterTest.cs

@@ -0,0 +1,32 @@
+using UnityEngine;
+using NUnit.Framework;
+using Object = UnityEngine.Object;
+
+namespace Mirror.Tests
+{
+    [TestFixture]
+    public class HeadlessFrameLimiterTest : MonoBehaviour
+    {
+        protected GameObject testGO;
+        protected HeadlessFrameLimiter comp;
+
+        [SetUp]
+        public void Setup()
+        {
+            testGO = new GameObject();
+            comp = testGO.AddComponent<HeadlessFrameLimiter>();
+        }
+
+        [TearDown]
+        public void Teardown()
+        {
+            Object.DestroyImmediate(testGO);
+        }
+
+        [Test]
+        public void StartOnHeadlessValue()
+        {
+            Assert.That(comp.serverTickRate, Is.EqualTo(30));
+        }
+    }
+}

Assets/Mirror/Tests/Runtime/HostSetup.cs

@@ -35,7 +35,6 @@ public class HostSetup<T> where T : NetworkBehaviour
             manager.server = networkManagerGo.GetComponent<NetworkServer>();
             server = manager.server;
             client = manager.client;
-            manager.startOnHeadless = false;
             sceneManager.client = client;
             sceneManager.server = server;
 

Assets/Mirror/Tests/Runtime/NetworkManagerTest.cs

@@ -11,8 +11,6 @@ public class NetworkManagerTest : HostSetup<MockComponent>
         [Test]
         public void VariableTest()
         {
-            Assert.That(manager.startOnHeadless, Is.False);
-            Assert.That(manager.serverTickRate, Is.EqualTo(30));
             Assert.That(manager.server.MaxConnections, Is.EqualTo(4));
         }