Unity3d的Log系统重构

 转载https://my.oschina.net/hava/blog/1618555

编者注

由于要重写Unity3d的Log系统，变更为自定义方式，按照Log4j的显示的内容方法

Unity3d的Log

一般在Unity3d中编写日志入下代码

Debug.Log("hello message");
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在UnityEditor和UnityEngine当中除了打印message以外，还会打印堆栈信息。性能低下，根据有经验的人讲解，在客户端打印大量日志，会严重降低渲染性能。

Unity3d的Debug原理

原理分析

在Rider中查看Debug.Log的实现，我们可以看到如下内容

public static void Log(object message)
{
    Debug.unityLogger.Log(LogType.Log, message);
}
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我们能够了解到，实质是调用了Debug.unityLogger

public static ILogger unityLogger
{
    get
    {
        return Debug.s_Logger;
    }
}
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unityLogger实质是调用了Debug.s_Logger，而在下面就定义了s_Logger的实现

internal static ILogger s_Logger = (ILogger) new Logger((ILogHandler) new DebugLogHandler());
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DebugLogHandler实质是调用的静态方法，根据UnityEngine各个平台的实现进行调用

using System;
using System.Runtime.CompilerServices;
using UnityEngine.Scripting;
 
namespace UnityEngine
{
  internal sealed class DebugLogHandler : ILogHandler
  {
    [ThreadAndSerializationSafe]
    [GeneratedByOldBindingsGenerator]
    [MethodImpl(MethodImplOptions.InternalCall)]
    internal static extern void Internal_Log(LogType level, string msg, [Writable] Object obj);
 
    [ThreadAndSerializationSafe]
    [GeneratedByOldBindingsGenerator]
    [MethodImpl(MethodImplOptions.InternalCall)]
    internal static extern void Internal_LogException(Exception exception, [Writable] Object obj);
 
    public void LogFormat(LogType logType, Object context, string format, params object[] args)
    {
      DebugLogHandler.Internal_Log(logType, string.Format(format, args), context);
    }
 
    public void LogException(Exception exception, Object context)
    {
      DebugLogHandler.Internal_LogException(exception, context);
    }
  }
}
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最终实现仅仅只有两个方法

internal static extern void Internal_Log(LogType level, string msg, [Writable] Object obj);
internal static extern void Internal_LogException(Exception exception, [Writable] Object obj);
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代码测试

Debug.unityLogger.Log(LogType.Log,"hello message");
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UnityEditor打印

hello message
UnityEngine.Logger:Log(LogType, Object)
InitController:Start() (at Assets/Scripts/Controller/InitController.cs:14)
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结论：无法解决减少堆栈信息打印的问题

UnityEngine.Application

根据UnityEngine.Application的LogCallback文档，我们能够了解和LogCallback相关的 Application.logMessageReceived和Application.logMessageReceivedThreaded:

public delegate void LogCallback(string condition, string stackTrace, LogType type);
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由于LogCallback使用的是delegate委托方法，则需要指定实现方法，如下Unity官方推荐实现方法

using UnityEngine;
using System.Collections;
 
public class ExampleClass : MonoBehaviour {
    public string output = "";
    public string stack = "";
    void OnEnable() {
        Application.logMessageReceived += HandleLog;
    }
    void OnDisable() {
        Application.logMessageReceived -= HandleLog;
    }
    void HandleLog(string logString, string stackTrace, LogType type) {
        output = logString;
        stack = stackTrace;
    }
}
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原理分析

logMessageReceived仅仅在 main 线程工作。也就是Unity的主线程当中。并且文档描述实现方法非线程安全。logMessageReceivedThreaded实现的代码必须是线程安全，支持从主线程之外进行访问。

    public static event Application.LogCallback logMessageReceived
    {
      add
      {
        Application.s_LogCallbackHandler += value;
        Application.SetLogCallbackDefined(true);
      }
      remove
      {
        Application.s_LogCallbackHandler -= value;
      }
    }
 
    public static event Application.LogCallback logMessageReceivedThreaded
    {
      add
      {
        Application.s_LogCallbackHandlerThreaded += value;
        Application.SetLogCallbackDefined(true);
      }
      remove
      {
        Application.s_LogCallbackHandlerThreaded -= value;
      }
    }
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CallLogCallback从CSharp的注解来看，就是需要本地代码进行调用。直接调用的，也就是说，会优先调用主线程的logCallbackHandler实现，然后无论是否主线程都调用callbackHandlerThreaded的实现

    [RequiredByNativeCode]
    private static void CallLogCallback(string logString, string stackTrace, LogType type, bool invokedOnMainThread)
    {
      if (invokedOnMainThread)
      {
        Application.LogCallback logCallbackHandler = Application.s_LogCallbackHandler;
        if (logCallbackHandler != null)
          logCallbackHandler(logString, stackTrace, type);
      }
      Application.LogCallback callbackHandlerThreaded = Application.s_LogCallbackHandlerThreaded;
      if (callbackHandlerThreaded == null)
        return;
      callbackHandlerThreaded(logString, stackTrace, type);
    }
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SetLogCallbackDefined

    [GeneratedByOldBindingsGenerator]
    [MethodImpl(MethodImplOptions.InternalCall)]
    private static extern void SetLogCallbackDefined(bool defined);
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日志系统设计

需求

• 不影响Unity
• 文件方式输出
• 支持Unity Debug
• 支持输出日志级别

Log4Net

根据之前 Java 的方式，Log4j很好用，首先决定仿照slf4j的接口方式进行使用。其次使用Log4net的实现，实现需求，只要不影响Unity运行即可。实际测试并未影响Unity运行。

接口设计

LoggerFactory

using log4net;
 
namespace Assets.Scripts.Utils.Log4Unity
{
    public class LoggerFactory
    {
        public static Log4Unity getLogger(string name)
        {
            return new Log4Unity(LogManager.GetLogger(name));
        }
    }
}
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Log4Unity：原本想直接使用logger，但是被Unity占用了

using System;
using System.IO;
using log4net;
using log4net.Config;
using UnityEngine;
 
namespace Assets.Scripts.Utils.Log4Unity
{
    public class Log4Unity
    {
        private ILog log;
        public Log4Unity(ILog log)
        {
            this.log = log;
        }
 
        public void debug(string message)
        {
            this.log.Debug(message);
            LogConfigurator.refresh();
        }
 
        public void info(string message)
        {
            this.log.Info(message);
            LogConfigurator.refresh();
        }
 
        public void warning(string message)
        {
            this.log.Warn(message);
            LogConfigurator.refresh();
        }
 
        public void error(string message)
        {
            Debug.LogError(message);
            if(!LogConfigurator.lazy_mode)
                this.log.Error(message);
            LogConfigurator.refresh();
        }
 
        public void exception(Exception exception)
        {
            Debug.LogException(exception);
            if(!LogConfigurator.lazy_mode)
                this.log.Warn(exception.ToString());
            LogConfigurator.refresh();
        }
 
        public void fatal(string message)
        {
            Debug.LogAssertion(message);
            if(!LogConfigurator.lazy_mode)
                this.log.Fatal(message);
            LogConfigurator.refresh();
        }
    }
 
    
}
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Log4Unity的初始化

Log4Unity初始化，使用Unity的MonoBehaviour来完成，同时打印些简单日志，检查日志文件位置

using System.IO;
using log4net;
using log4net.Appender;
using log4net.Config;
using log4net.Core;
using UnityEngine;
 
namespace Assets.Scripts.Utils.Log4Unity
{
public class LogConfigurator : MonoBehaviour
    {
        private static readonly string config_path = "log4unity.properties";
        private static readonly ILog logger = LogManager.GetLogger("LogConfigurator");
        private static bool config_load = false;
        public static bool refresh_realtime = true;
        public static bool lazy_mode = true;
 
        private static FileInfo fileInfo = new FileInfo(config_path);
        
        private void Awake()
        {
            if (fileInfo.Exists)
            {
                XmlConfigurator.Configure(fileInfo);
                IAppender appender = LogManager.GetRepository().GetAppenders()[0];
                if (appender.Name.Equals("FileAppender"))
                {
                    FileAppender fileAppender = (FileAppender) appender;
 
                    Debug.Log("[logpath]:" + fileAppender.File);
                }
                
                
                config_load = true;
            }
            else
            {
                Debug.LogError("class Log4Unity method Awake configfile " + fileInfo.FullName + " is not existed.");
            }
        }
 
        private void OnEnable()
        {
            logger.Debug("method OnEnable");
            if(config_load == true)
            {
                Application.logMessageReceivedThreaded += ThreadLog;
            }
        }
 
        private void ThreadLog(string condition, string stackTrace, LogType type)
        {
            if (LogType.Warning.Equals(type))
            {
                logger.Warn(condition);
            }
            else if(LogType.Log.Equals(type))
            {
                logger.Info(condition);
            }
            
            // fixed:double print
            if(lazy_mode)
                if (LogType.Exception.Equals(type))
                {
                    logger.Warn(condition);
                }
                else if (LogType.Error.Equals(type))
                {
                    logger.Error(condition);
                }
                else if (LogType.Assert.Equals(type))
                {
                    logger.Fatal(condition);
                }
 
            refresh();
        }
 
        public static void refresh()
        {
            if(refresh_realtime)
                fileInfo.Refresh();
        }
 
        private void OnDisable()
        {
            logger.Debug("method OnDisable");
            if(config_load == true)
            {
                Application.logMessageReceivedThreaded -= ThreadLog;
            }
        }
 
        private void OnDestroy()
        {
            logger.Debug("method OnDestroy");
            fileInfo.Refresh();
        }
    }
}
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其他配置

log4unity.properties

注意放到exe

<?xml version='1.0' encoding='UTF-8'?>
<log4net>
	<appender name="FileAppender" type="log4net.Appender.FileAppender">
		<file value="log4unity.log" />
		<appendToFile value="true" />
		<layout type="log4net.Layout.PatternLayout">
			<conversionPattern value="%date %-5level --- [%-5thread] %-20logger : %message%newline" />
		</layout>
	</appender>
	
	<root>
        <level value="DEBUG" />
		<appender-ref ref="FileAppender" />
    </root>
</log4net>
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log4net.dll

注意：Unity在Windows上有两种运行时DotNet2.0和DotNet4.6，都需要加载正确的dll版本。还有UnityEditor的行为在两个 DotNet 版本，运行的目录不同，注意日志的输出位置。build之后不会出现问题。

使用方法

public class FpsCounter : MonoBehaviour
    {
        private static readonly Log4Unity logger = LoggerFactory.getLogger("FpsCounter");
        
        ....
        
        private void Start()
        {
            logger.info("method Start");
            ....
        }
 
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吐槽

最近开的坑有点多，先把这个补上