Configuration

Core Principles

1. Options pattern always — Never read IConfiguration directly in services. Bind configuration sections to strongly-typed classes with validation.
2. Validate on startup — Use ValidateDataAnnotations() and ValidateOnStart() to catch misconfiguration before the first request.
3. Secrets never in source — Use user secrets in development, Azure Key Vault or environment variables in production. Never commit secrets to git.
4. Configuration layering — appsettings.json → appsettings.{Environment}.json → environment variables → user secrets. Later sources override earlier ones.

Patterns

Options Pattern

// Options class with validation attributes
public class DatabaseOptions
{
    public const string SectionName = "Database";