JavaScriptServices/src/Microsoft.AspNetCore.SpaServices.Extensions/Util/LoggerFinder.cs

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using Microsoft.AspNetCore.Builder;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Console;

namespace Microsoft.AspNetCore.SpaServices.Util
{
    internal static class LoggerFinder
    {
        public static ILogger GetOrCreateLogger(
            IApplicationBuilder appBuilder,
            string logCategoryName)
        {
            // If the DI system gives us a logger, use it. Otherwise, set up a default one.
            var loggerFactory = appBuilder.ApplicationServices.GetService<ILoggerFactory>();
            var logger = loggerFactory != null
                ? loggerFactory.CreateLogger(logCategoryName)
                : new ConsoleLogger(logCategoryName, null, false);
            return logger;
        }
    }
}