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public interface ILoggerFactory : IDisposable { ILogger CreateLogger(string categoryName); void AddProvider(ILoggerProvider provider); }
ILoggerFactory
是日志記錄器的工廠接口類,用于配置日志記錄系統(tǒng)并創(chuàng)建Logger實(shí)例的類,默認(rèn)實(shí)現(xiàn)兩個(gè)接口方法為,通過CreateLogger()
方法來創(chuàng)建ILogger
實(shí)例,(其中參數(shù)categoryName
是一個(gè)日志類別,用于調(diào)用Logger
所在類的全名,類別指明日志消息是誰寫入的,一般我們將日志所屬的的組件、服務(wù)或者消息類型名稱作為日志類別。) 而AddProvider()
添加日志記錄提供程序,向日志系統(tǒng)注冊(cè)添加一個(gè)ILoggerProvider
。工廠接口類的默認(rèn)實(shí)現(xiàn)類為LoggerFactory
, 我們繼續(xù)往下看:
ILoggerFactory 的默認(rèn)實(shí)現(xiàn)是 LoggerFactory ,在構(gòu)造函數(shù)中,如下:
public class LoggerFactory : ILoggerFactory { private static readonly LoggerRuleSelector RuleSelector = new LoggerRuleSelector(); private readonly Dictionary<string, Logger> _loggers = new Dictionary<string, Logger>(StringComparer.Ordinal); private readonly List<ProviderRegistration> _providerRegistrations = new List<ProviderRegistration>(); private readonly object _sync = new object(); private volatile bool _disposed; private IDisposable _changeTokenRegistration; private LoggerFilterOptions _filterOptions; private LoggerExternalScopeProvider _scopeProvider; public LoggerFactory() : this(Enumerable.Empty<ILoggerProvider>()) { } public LoggerFactory(IEnumerable<ILoggerProvider> providers) : this(providers, new StaticFilterOptionsMonitor(new LoggerFilterOptions())) { } public LoggerFactory(IEnumerable<ILoggerProvider> providers, LoggerFilterOptions filterOptions) : this(providers, new StaticFilterOptionsMonitor(filterOptions)) { } public LoggerFactory(IEnumerable<ILoggerProvider> providers, IOptionsMonitor<LoggerFilterOptions> filterOption) { foreach (var provider in providers) { AddProviderRegistration(provider, dispose: false); } _changeTokenRegistration = filterOption.OnChange(RefreshFilters); RefreshFilters(filterOption.CurrentValue); } private void AddProviderRegistration(ILoggerProvider provider, bool dispose) { _providerRegistrations.Add(new ProviderRegistration { Provider = provider, ShouldDispose = dispose }); if (provider is ISupportExternalScope supportsExternalScope) { if (_scopeProvider == null) { _scopeProvider = new LoggerExternalScopeProvider(); } supportsExternalScope.SetScopeProvider(_scopeProvider); } } }
從LoggerFactory
中 的構(gòu)造函數(shù)中可以發(fā)現(xiàn),通過注入的方式獲取到ILoggerProvider
(這個(gè)在下文中會(huì)說明),并調(diào)用AddProviderRegistration
方法添加注冊(cè)程序,將ILoggerProvider
保存到ProviderRegistration
集合中。
AddProviderRegistration 方法:
這是一個(gè)日志程序提供器,將
ILoggerProvider
保存到ProviderRegistration
集合中。當(dāng)日志提供器實(shí)現(xiàn) ISupportExternalScope 接口將單例 LoggerExternalScopeProvider 保存到 provider._scopeProvider 中。
ProviderRegistration集合:
private struct ProviderRegistration { public ILoggerProvider Provider; public bool ShouldDispose; }
其中的 ShouldDispose 字段標(biāo)識(shí)在在
LoggerFactory
生命周期結(jié)束之后,該ILoggerProvider
是否需要釋放。雖然在系統(tǒng)中LoggerFactory
為單例模式,但是其提供了一個(gè)靜態(tài)方法生成一個(gè)可釋放的DisposingLoggerFactory
。
在LoggerFactory
實(shí)現(xiàn)默認(rèn)的接口方法CreateLogger()
,AddProvider()
查看源碼如下:
創(chuàng)建ILogger
實(shí)例,CreateLogger()
源碼如下:
public class LoggerFactory : ILoggerFactory { private readonly Dictionary<string, Logger> _loggers = new Dictionary<string, Logger>(StringComparer.Ordinal); private readonly List<ProviderRegistration> _providerRegistrations = new List<ProviderRegistration>(); private struct ProviderRegistration { public ILoggerProvider Provider; public bool ShouldDispose; } public ILogger CreateLogger(string categoryName) { if (CheckDisposed()) { throw new ObjectDisposedException(nameof(LoggerFactory)); } lock (_sync) { if (!_loggers.TryGetValue(categoryName, out var logger)) { logger = new Logger { Loggers = CreateLoggers(categoryName), }; (logger.MessageLoggers, logger.ScopeLoggers) = ApplyFilters(logger.Loggers); _loggers[categoryName] = logger; } return logger; } } private LoggerInformation[] CreateLoggers(string categoryName) { var loggers = new LoggerInformation[_providerRegistrations.Count]; for (var i = 0; i < _providerRegistrations.Count; i++) { loggers[i] = new LoggerInformation(_providerRegistrations[i].Provider, categoryName); } return loggers; } }
從源碼可以看出,CreateLogger
方法中,會(huì)檢測(cè)資源是否被釋放,在方法中,根據(jù)內(nèi)部定義的字典集合Dictionary<string, Logger> _loggers
,判斷字典中是否存在對(duì)應(yīng)的Logger
屬性對(duì)象,如果不存在,會(huì)調(diào)用CreateLoggers
方法根據(jù)之前注冊(cè)的的所有ILoggerProvider
所創(chuàng)建出來 ProviderRegistration 集合來實(shí)現(xiàn)創(chuàng)建Logger
屬性集合(根據(jù)日志類別生成了對(duì)應(yīng)實(shí)際的日志寫入類FileLogger
、ConsoleLogger
等),并通過字典集合的方式保存categoryName
和對(duì)應(yīng)的Logger
。
創(chuàng)建 Logger 需要的
LoggerInformation[]
internal readonly struct LoggerInformation { public LoggerInformation(ILoggerProvider provider, string category) : this() { ProviderType = provider.GetType(); Logger = provider.CreateLogger(category); Category = category; ExternalScope = provider is ISupportExternalScope; } public ILogger Logger { get; } public string Category { get; } public Type ProviderType { get; } public bool ExternalScope { get; } }
根據(jù)注冊(cè)的ILoggerProvider,創(chuàng)建
ILogger
其中的字段說明:Logger :具體日志類別寫入途徑實(shí)現(xiàn)類
Category : 日志類別名稱
ProviderType : 日志提供器Type
ExternalScope :是否支持 ExternalScope
繼續(xù)看CreateLogger
方法,在創(chuàng)建Logger
之后,還調(diào)用了ApplyFilters
方法:
private (MessageLogger[] MessageLoggers, ScopeLogger[] ScopeLoggers) ApplyFilters(LoggerInformation[] loggers) { var messageLoggers = new List<MessageLogger>(); var scopeLoggers = _filterOptions.CaptureScopes ? new List<ScopeLogger>() : null; foreach (var loggerInformation in loggers) { RuleSelector.Select(_filterOptions, loggerInformation.ProviderType, loggerInformation.Category, out var minLevel, out var filter); if (minLevel != null && minLevel > LogLevel.Critical) { continue; } messageLoggers.Add(new MessageLogger(loggerInformation.Logger, loggerInformation.Category, loggerInformation.ProviderType.FullName, minLevel, filter)); if (!loggerInformation.ExternalScope) { scopeLoggers?.Add(new ScopeLogger(logger: loggerInformation.Logger, externalScopeProvider: null)); } } if (_scopeProvider != null) { scopeLoggers?.Add(new ScopeLogger(logger: null, externalScopeProvider: _scopeProvider)); } return (messageLoggers.ToArray(), scopeLoggers?.ToArray()); }
由源碼可以看出,
MessageLogger[] 集合取值:
在獲取LoggerInformation[]
后進(jìn)行傳參,進(jìn)行遍歷,根據(jù)RuleSelector
過濾器,從配置文件中讀取對(duì)應(yīng)的日志級(jí)別,過濾器會(huì)返回獲取最低級(jí)別和對(duì)應(yīng)的一條過濾規(guī)則,如果配置文件中沒有對(duì)應(yīng)的配置,默認(rèn)取全局最低級(jí)別(MinLevel),如果讀取到的日志級(jí)別大于LogLevel.Critical
,則將其加入MessageLogger[]
。
過濾器的規(guī)則:
選擇當(dāng)前記錄器類型的規(guī)則,如果沒有,請(qǐng)選擇未指定記錄器類型的規(guī)則
選擇最長匹配類別的規(guī)則
如果沒有與類別匹配的內(nèi)容,則采用所有沒有類別的規(guī)則
如果只有一條規(guī)則,則使用它的級(jí)別和過濾器
如果有多個(gè)規(guī)則,請(qǐng)選擇使用最后一條。
如果沒有適用的規(guī)則,請(qǐng)使用全局最低級(jí)別
通過MessageLogger[]
添加消息日志集合
internal readonly struct MessageLogger { public MessageLogger(ILogger logger, string category, string providerTypeFullName, LogLevel? minLevel, Func<string, string, LogLevel, bool> filter) { Logger = logger; Category = category; ProviderTypeFullName = providerTypeFullName; MinLevel = minLevel; Filter = filter; } public ILogger Logger { get; } public string Category { get; } private string ProviderTypeFullName { get; } public LogLevel? MinLevel { get; } public Func<string, string, LogLevel, bool> Filter { get; } public bool IsEnabled(LogLevel level) { if (MinLevel != null && level < MinLevel) { return false; } if (Filter != null) { return Filter(ProviderTypeFullName, Category, level); } return true; } } internal readonly struct ScopeLogger { public ScopeLogger(ILogger logger, IExternalScopeProvider externalScopeProvider) { Logger = logger; ExternalScopeProvider = externalScopeProvider; } public ILogger Logger { get; } public IExternalScopeProvider ExternalScopeProvider { get; } public IDisposable CreateScope<TState>(TState state) { if (ExternalScopeProvider != null) { return ExternalScopeProvider.Push(state); } return Logger.BeginScope<TState>(state); } }
在MessageLogger[]
中帶有MinLevel屬性和Filter委托兩種過濾配置,而這兩種配置的來源,在上一章中可以看到,分別是從配置文件(AddConfiguration)和直接使用委托(AddFilter)來進(jìn)行配置的。
再由上面的IsEnabled
方法可以看出,會(huì)先使用 MinLevel
過濾,再使用 Filter
進(jìn)行過濾。所以這兩者存在優(yōu)先級(jí)。
ScopeLogger[ ] 取值 :
如果 ILoggerProvider
實(shí)現(xiàn)了ISupportExternalScope
接口,那么使用LoggerExternalScopeProvider
作為Scope
功能的實(shí)現(xiàn)。反之,使用ILogger
作為其Scope
功能的實(shí)現(xiàn)。
LoggerExternalScopeProvider
:
通過
Scope
組成了一個(gè)單向鏈表,每次beginscope
向鏈表末端增加一個(gè)新的元素,Dispose
的時(shí)候,刪除鏈表最末端的元素。我們知道LoggerExternalScopeProvider
在系統(tǒng)中是單例模式,多個(gè)請(qǐng)求進(jìn)來,加入線程池處理。通過使用AsyncLoca
來實(shí)現(xiàn)不同線程間數(shù)據(jù)獨(dú)立。有兩個(gè)地方開啟了日志作用域:
1、通過
socket
監(jiān)聽到請(qǐng)求后,將KestrelConnection
加入線程池,線程池調(diào)度執(zhí)行IThreadPoolWorkItem.Execute()
方法。在這里開啟了一次2、在構(gòu)建請(qǐng)求上下文對(duì)象的時(shí)候(
HostingApplication.CreateContext()
),開啟了一次
由上源碼可以得出:在工廠記錄器類中,通過系統(tǒng)依賴注入的方式解析所有注冊(cè)的ILoggerProvider
,然后調(diào)用其中的CreateLogger
方法實(shí)現(xiàn)創(chuàng)建一個(gè)Logger
實(shí)例對(duì)象,而這個(gè)Logger
實(shí)例對(duì)象會(huì)根據(jù)根據(jù)注冊(cè)的ILoggerProvider
創(chuàng)建需要的 LoggerInformation[]
,并將此對(duì)象作為參數(shù)進(jìn)行ApplyFilters
過濾器篩選,得到對(duì)應(yīng)的最低等級(jí)或過濾規(guī)則,最后通過調(diào)用Log
方法日志記錄的時(shí)候,會(huì)遍歷MessageLogger[]
集合,根據(jù)logger
日志類別對(duì)應(yīng)實(shí)際不同的日志寫入類,調(diào)用ILoggerProvider
具體實(shí)現(xiàn)類 (可以看下文說明) 中的Log
方法。
AddProviderRegistration→CreateLoggers→LoggerInformation[]→ApplyFilters→MessageLogger[]→Log→ILoggerProvider ( 執(zhí)行具體類中的Log方法 )
ILoggerFactory
來源:應(yīng)用程序在啟動(dòng)初始化的時(shí)候會(huì)通過注入的方式
CreateDefaultBuilder
→ConfigureLogging
→AddLogging
public static IServiceCollection AddLogging(this IServiceCollection services, Action<ILoggingBuilder> configure) { if (services == null) { throw new ArgumentNullException(nameof(services)); } services.AddOptions(); services.TryAdd(ServiceDescriptor.Singleton<ILoggerFactory, LoggerFactory>()); services.TryAdd(ServiceDescriptor.Singleton(typeof(ILogger<>), typeof(Logger<>))); services.TryAddEnumerable(ServiceDescriptor.Singleton<IConfigureOptions<LoggerFilterOptions>>( new DefaultLoggerLevelConfigureOptions(LogLevel.Information))); configure(new LoggingBuilder(services)); return services; }
實(shí)現(xiàn)將把
ILoggerFactory
對(duì)象以依賴注入的方式托管到集合容器中,為程序調(diào)用提供使用。
創(chuàng)建ILogger
實(shí)例的類型,根據(jù)日志類別名稱創(chuàng)建一個(gè)新的ILogger
實(shí)例
public interface ILoggerProvider : IDisposable { ILogger CreateLogger(string categoryName); }
這個(gè)是具體的日志寫入類,在工廠記錄器中我們已經(jīng)提到了這個(gè),在LoggerInformation[]
中會(huì)根據(jù)日志類別注冊(cè)對(duì)應(yīng)的ILoggerProvider
,在系統(tǒng)中我們就可以通過ILogger
同時(shí)向多個(gè)途經(jīng)寫入日志信息。(這也是對(duì)上一篇中留下的問題進(jìn)行再次說明)
ILoogerProvider
繼承了IDisposable
接口,如果某個(gè)具體的ILoggerProvider
對(duì)象需要釋放資源,就可以將相關(guān)的操作實(shí)現(xiàn)在Dispose
方法中。
默認(rèn)的實(shí)現(xiàn)方式為多個(gè),官方實(shí)現(xiàn)的由ConsoleLoggerProvider
、DebugLoggerProvider
、EventSourceLoggerProvider
、EventLogLoggerProvider
、TraceSourceLoggerProvider
以ConsoleLoggerProvider
為列
[ProviderAlias("Console")] public class ConsoleLoggerProvider : ILoggerProvider, ISupportExternalScope { private readonly IOptionsMonitor<ConsoleLoggerOptions> _options; private readonly ConcurrentDictionary<string, ConsoleLogger> _loggers; private readonly ConsoleLoggerProcessor _messageQueue; private IDisposable _optionsReloadToken; private IExternalScopeProvider _scopeProvider = NullExternalScopeProvider.Instance; public ConsoleLoggerProvider(IOptionsMonitor<ConsoleLoggerOptions> options) { _options = options; _loggers = new ConcurrentDictionary<string, ConsoleLogger>(); ReloadLoggerOptions(options.CurrentValue); _optionsReloadToken = _options.OnChange(ReloadLoggerOptions); _messageQueue = new ConsoleLoggerProcessor(); if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows)) { _messageQueue.Console = new WindowsLogConsole(); _messageQueue.ErrorConsole = new WindowsLogConsole(stdErr: true); } else { _messageQueue.Console = new AnsiLogConsole(new AnsiSystemConsole()); _messageQueue.ErrorConsole = new AnsiLogConsole(new AnsiSystemConsole(stdErr: true)); } } private void ReloadLoggerOptions(ConsoleLoggerOptions options) { foreach (var logger in _loggers) { logger.Value.Options = options; } } public ILogger CreateLogger(string name) { return _loggers.GetOrAdd(name, loggerName => new ConsoleLogger(name, _messageQueue) { Options = _options.CurrentValue, ScopeProvider = _scopeProvider }); } public void Dispose() { _optionsReloadToken?.Dispose(); _messageQueue.Dispose(); } public void SetScopeProvider(IExternalScopeProvider scopeProvider) { _scopeProvider = scopeProvider; foreach (var logger in _loggers) { logger.Value.ScopeProvider = _scopeProvider; } } }
在ConsoleLoggerProvider
類型定義中,標(biāo)注了ProviderAliasAttribute
特性,并設(shè)置別名為Console
,所以在配置過濾規(guī)則的時(shí)候,可以直接使用這個(gè)名稱。ILogger
的創(chuàng)建實(shí)現(xiàn)了具體日志類ConsoleLogger
。
表示用于執(zhí)行日志記錄的類型,是系統(tǒng)中寫入日志的統(tǒng)一入口。
public interface ILogger { void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception exception, Func<TState, Exception, string> formatter); bool IsEnabled(LogLevel logLevel); IDisposable BeginScope<TState>(TState state); }
定義了三個(gè)方法,Log<TState>()
用于寫入日志,IsEnabled()
用于檢查判斷日志級(jí)別是否開啟,BeginScope()
用于指日志作用域。
ILogger
執(zhí)行記錄接口類的具體實(shí)現(xiàn)Logger
如下:
internal class Logger : ILogger { public LoggerInformation[] Loggers { get; set; } public MessageLogger[] MessageLoggers { get; set; } public ScopeLogger[] ScopeLoggers { get; set; } public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception exception, Func<TState, Exception, string> formatter) { var loggers = MessageLoggers; if (loggers == null) { return; } List<Exception> exceptions = null; for (var i = 0; i < loggers.Length; i++) { ref readonly var loggerInfo = ref loggers[i]; if (!loggerInfo.IsEnabled(logLevel)) { continue; } LoggerLog(logLevel, eventId, loggerInfo.Logger, exception, formatter, ref exceptions, state); } if (exceptions != null && exceptions.Count > 0) { ThrowLoggingError(exceptions); } static void LoggerLog(LogLevel logLevel, EventId eventId, ILogger logger, Exception exception, Func<TState, Exception, string> formatter, ref List<Exception> exceptions, in TState state) { try { logger.Log(logLevel, eventId, state, exception, formatter); } catch (Exception ex) { if (exceptions == null) { exceptions = new List<Exception>(); } exceptions.Add(ex); } } } public bool IsEnabled(LogLevel logLevel) { var loggers = MessageLoggers; if (loggers == null) { return false; } List<Exception> exceptions = null; var i = 0; for (; i < loggers.Length; i++) { ref readonly var loggerInfo = ref loggers[i]; if (!loggerInfo.IsEnabled(logLevel)) { continue; } if (LoggerIsEnabled(logLevel, loggerInfo.Logger, ref exceptions)) { break; } } if (exceptions != null && exceptions.Count > 0) { ThrowLoggingError(exceptions); } return i < loggers.Length ? true : false; static bool LoggerIsEnabled(LogLevel logLevel, ILogger logger, ref List<Exception> exceptions) { try { if (logger.IsEnabled(logLevel)) { return true; } } catch (Exception ex) { if (exceptions == null) { exceptions = new List<Exception>(); } exceptions.Add(ex); } return false; } } }
源碼中MessageLogger[]
在上文已經(jīng)提到了,其中保存了在配置中啟用的那些對(duì)應(yīng)的ILogger
。
需要注意的是,由于配置文件更改后,會(huì)調(diào)用
ApplyFilters()
方法,并為MessageLogger[]
賦新值,所以在遍歷之前,需要保存當(dāng)前值,再進(jìn)行處理。否則會(huì)出現(xiàn)修改異常。
在系統(tǒng)中統(tǒng)一寫入日志的入口,通過日志等級(jí)作為參數(shù)調(diào)用其IsEnabled
方法來確定當(dāng)前日志是否執(zhí)行對(duì)應(yīng)具體日志的實(shí)現(xiàn)類,當(dāng)符合條件執(zhí)行具體日志輸出到對(duì)應(yīng)的寫入途徑中會(huì)調(diào)用對(duì)應(yīng)的Log
方法(需要提供一個(gè)EventId
來標(biāo)識(shí)當(dāng)前日志事件)
ILogger
默認(rèn)的實(shí)現(xiàn)方式為多個(gè),官方實(shí)現(xiàn)的由ConsoleLogger
、DebugLogger
、EventSourceLogger
、EventLogLogger
、TraceSourceLogger
具體日志實(shí)現(xiàn)類代表不同的日志寫入途徑。
以上就是關(guān)于“.Net Core日志記錄器實(shí)例分析”這篇文章的內(nèi)容,相信大家都有了一定的了解,希望小編分享的內(nèi)容對(duì)大家有幫助,若想了解更多相關(guān)的知識(shí)內(nèi)容,請(qǐng)關(guān)注億速云行業(yè)資訊頻道。
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