UserService.cs

using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using System.IO;

namespace CloudWorker.ServiceInterface;

public abstract class UserService<TOptions> : UserServiceBase where TOptions : class
{
    protected TOptions? _options;

    protected virtual string _settingsFileName { get; } = string.Empty;

    protected virtual string _environmentPrefix { get; } = string.Empty;

    public UserService(ILogger logger, IConfiguration hostConfig) : base(logger, hostConfig)
    {
        LoadConfiguration();
    }

    protected virtual void LoadConfiguration()
    {
        var builder = new ConfigurationBuilder();

        if (!string.IsNullOrEmpty(_settingsFileName))
        {
            var configFileBase = Path.GetDirectoryName(this.GetType().Assembly.Location);
            if (string.IsNullOrWhiteSpace(configFileBase))
            {
                configFileBase = Directory.GetCurrentDirectory();
            }

            _logger.LogInformation("Look up configuration file '{configFile}' in '{configFileBase}'.", _settingsFileName, configFileBase);

            builder.SetBasePath(configFileBase).AddJsonFile(_settingsFileName, true);
        }

        builder.AddEnvironmentVariables(_environmentPrefix);

        var configuration = builder.Build();
        _options = configuration.Get<TOptions>();
    }
}