How to create a LoggerFactory with a ConsoleLoggerProvider?

Question

The ConsoleLoggerProvider has four constructors:

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

Three of them are declared obsolete with this message:

This method is obsolete and will be removed in a future version.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.

With constructor #3, creating a LoggerFactory with a ConsoleLoggerProvider is straightforward (as documented on Entity Framework Core - Logging):

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

But since it's deprecated, we are left with constructor #2. Here's what I found to be equivalent:

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 }); 

This seems overly complicated, am I missing something simpler?

Answer 1

In .NET Core 2.2, you can build an ILoggerFactory without using obsolete methods through Microsoft's dependency injection framework. It's a little less verbose than the version where everything is constructed by hand. Here’s how:

using Microsoft.Extensions.DependencyInjection; using Microsoft.Extensions.Logging;  IServiceCollection serviceCollection = new ServiceCollection(); serviceCollection.AddLogging(builder => builder     .AddConsole()     .AddFilter(level => level >= LogLevel.Information) ); var loggerFactory = serviceCollection.BuildServiceProvider().GetService<ILoggerFactory>(); 

And in .NET Core 3.0, you can use LoggerFactory.Create:

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

See also:

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