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Curiosus.Configuration

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Building blocks for strongly typed application configuration: options validation (IValidatableOptions), options logging (ILoggableOptions, ConfigurationPrinter) and a base class for file-based configuration providers. Most Curiosus packages validate their options with these types.

Installation​

dotnet add package Curiosus.Configuration

Usage​

Implement IValidatableOptions to validate options and ILoggableOptions to print them at startup:

using Curiosus.Configuration;

public class AppOptions : IValidatableOptions, ILoggableOptions
{
    public string ServiceUrl { get; set; } = null!;
    public int Port { get; set; } = 8080;

    public IReadOnlyCollection<ConfigurationValidationError> Validate(string? prefix = null)
    {
        var errors = new ConfigurationValidationErrorCollection(prefix);
        errors.AddErrorIf(String.IsNullOrWhiteSpace(ServiceUrl), nameof(ServiceUrl), "can't be empty");
        errors.AddErrorIf(Port <= 0, nameof(Port), "must be positive");
        return errors;
    }
}

var options = builder.Configuration.Get<AppOptions>()!;
options.AssertValid(); // throws ConfigurationValidationException with all errors
Console.WriteLine(new ConfigurationPrinter().GetLog(options)); // prints all public properties

ConfigurationValidationErrorCollection prefixes field names (prefix:Field), which is handy for nested options.

Configuration providers​

ConfigurationProviderBase<T> (exposed as IConfigurationProvider<T>) loads, in order: config, config.secret, then — when ASPNETCORE_ENVIRONMENT is set and is not Production — config.{env}, config.{env}.secret, config.{env}.{USER} and config.{env}.{USER}.secret, then environment variables and command line arguments. Only config is required (unless isConfigOptional is true). Derived classes decide the file format; see Curiosus.Configuration.YML for YAML.

See also​