The third one use ConfigureServices
which is a public method in the WebHostBuilder
. And the first one use ConfigureLogging
which is one of IHostBuilder
‘s extension method in HostingHostBuilderExtensions
.
And they both call the IServiceCollection
‘s extension method AddLogging
in LoggingServiceCollectionExtensions
under Microsoft.Extensions.Logging
package. The AddLogging
method first try to add two singleton ILoggerFactory
and ILogger<>
and an enumerable of LoggerFilterOptions
. Then do the action for logging(ILoggingBuilder
) which finally calls AddProvider
method to add the log providers implemented by these providers(Console, Azure) and calls SetMinimumLevel
to add LoggerFilterOptions
The second method directly adds the log providers to LoggerFactory
. And these providers are called in LoggerFactory
when logging methods are called.
As for orders, the second and third methods are called by WebHostBuilder
‘s UseStartup<TStartup>
method.