c# - 如何使用 ConsoleLoggerProvider 创建 LoggerFactory？

Question

ConsoleLoggerProvider有四个构造函数:

1. ConsoleLoggerProvider(IConsoleLoggerSettings)
2. ConsoleLoggerProvider(IOptionsMonitor<ConsoleLoggerOptions>)
3. ConsoleLoggerProvider(Func<String,LogLevel,Boolean>, Boolean)
4. ConsoleLoggerProvider(Func<String,LogLevel,Boolean>, Boolean, Boolean)

其中三个已被声明为过时，并显示以下消息:

This method is obsolete and will be removed in a future version. The recommended alternative is using LoggerFactory to configure filtering and ConsoleLoggerOptions to configure logging options.

使用构造函数 #3，创建 LoggerFactory与 ConsoleLoggerProvider很简单(如 Entity Framework Core - Logging 中所述):

var loggerFactory = new LoggerFactory(new[] { new ConsoleLoggerProvider((category, level) => level >= LogLevel.Information, true) });

但由于它已被弃用，我们只剩下构造函数 #2。这是我发现的等效内容:

var configureNamedOptions = new ConfigureNamedOptions<ConsoleLoggerOptions>("", null);
var optionsFactory = new OptionsFactory<ConsoleLoggerOptions>(new []{ configureNamedOptions }, Enumerable.Empty<IPostConfigureOptions<ConsoleLoggerOptions>>());
var optionsMonitor = new OptionsMonitor<ConsoleLoggerOptions>(optionsFactory, Enumerable.Empty<IOptionsChangeTokenSource<ConsoleLoggerOptions>>(), new OptionsCache<ConsoleLoggerOptions>());
var loggerFactory = new LoggerFactory(new[] { new ConsoleLoggerProvider(optionsMonitor) }, new LoggerFilterOptions { MinLevel = LogLevel.Information });

这看起来过于复杂，我是否缺少一些更简单的东西？

Answer 1

在 Microsoft.Extensions.Logging 3.0+，你可以使用更简单的LoggerFactory.Create :

var loggerFactory = LoggerFactory.Create(builder =>
{
    builder.AddFilter("Microsoft", LogLevel.Warning)
           .AddFilter("System", LogLevel.Warning)
           .AddFilter("SampleApp.Program", LogLevel.Debug)
           .AddConsole();
});

对于 Microsoft.Extensions.Logging 版本 2.2+，您可以通过 Microsoft 的依赖项注入(inject)框架构建 ILoggerFactory，而无需使用过时的方法。它比 2.1 版本稍微简洁一些，在 2.1 版本中，所有内容都是手工构建的。方法如下:

var serviceCollection = new ServiceCollection();
serviceCollection.AddLogging(builder => builder
    .AddConsole()
    .AddFilter(level => level >= LogLevel.Information)
);
var loggerFactory = serviceCollection.BuildServiceProvider()
    .GetService<ILoggerFactory>();

另请参阅:

• Migrate from Microsoft.Extensions.Logging 2.1 to 2.2 or 3.0