Validating Connection Strings on .NET Startup

Initial Host Configuration

using System.Data.Common;
using Microsoft.Data.SqlClient;
using Microsoft.Data.Sqlite;
using Microsoft.Extensions.Options;
using Microsoft.IdentityModel.Tokens;
using WorkerServiceDatabase;


IHost host = Host.CreateDefaultBuilder(args)
    .ConfigureServices(services =>
    {
        services 
            // validate connection strings
            .ValidateConnectionStrings()
            .ValidateOnStart();
        
        services.AddHostedService<Worker>();
    })
    .Build();


host.Run();


public static class ConnectionStringExtensions
{
    public static OptionsBuilder<ConnectionStrings> 
        ValidateConnectionStrings(this IServiceCollection services)
    {
        return services
            .AddOptions<ConnectionStrings>()
            .BindConfiguration("ConnectionStrings")
            .Validate(c => c.Validate(), "Could not connect to 1 or more databases.");
    }
}


public class ConnectionStrings
    : Dictionary<string,string>
{
    public ConnectionStrings()
    {
        // these are the key names
        DbProviderFactories.RegisterFactory("Sqlite", SqliteFactory.Instance);
        DbProviderFactories.RegisterFactory("SqlServer", SqlClientFactory.Instance);
    }
    
    public bool Validate()
    {
        // can't inject logger :(
        var logger = LoggerFactory
            .Create(cfg => cfg.AddConsole().AddDebug())
            .CreateLogger("ConnectionStrings");
        
        List<Exception> errors = new();
        foreach (var (key, connectionString) in this)
        {
            try
            {
                var factory = DbProviderFactories.GetFactory(key);
                using var connection = factory.CreateConnection();
                if (connection is null) {
                    throw new Exception($"\"{key}\" did not have a valid database provider registered");
                }


                connection.ConnectionString = connectionString;
                connection.Open();
            }
            catch (Exception e)
            {
                var message = $"Could not connect to \"{key}\".";
                logger.LogError(message);
                errors.Add(new Exception(message, e));
            }
        }


        return errors.IsNullOrEmpty();
    }
}

ConnectionString Configuration

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "ConnectionStrings": {
      "Sqlite": "Data Source=database.db",
      "SqlServer": "Data Source=localhost,11433;Initial Catalog=DBName;User Id=sa;Password=password;Encrypt=false"
    }
}