feat(config): add multiple server instances support

- Add ServersConfig and ServerInstanceConfig structs
- Support configuring multiple named server instances
- Add global timeout defaults with per-instance overrides
- Add TLS configuration options (SSL cert/key, self-signed, AutoTLS)
- Add validation for server configurations
- Add helper methods for applying defaults and getting default server
- Add conversion helper to avoid import cycles

Author: warkanum

cmd/testserver/main.go

@@ -39,7 +39,6 @@ func main() {
 		logger.UpdateLoggerPath(cfg.Logger.Path, cfg.Logger.Dev)
 	}
 	logger.Info("ResolveSpec test server starting")
-	logger.Info("Configuration loaded - Server will listen on: %s", cfg.Server.Addr)
 
 	// Initialize database manager
 	ctx := context.Background()
@@ -73,47 +72,30 @@ func main() {
 	// Create server manager
 	mgr := server.NewManager()
 
-	// Parse host and port from addr
-	host := ""
-	port := 8080
-	if cfg.Server.Addr != "" {
-		// Parse addr (format: ":8080" or "localhost:8080")
-		if cfg.Server.Addr[0] == ':' {
-			// Just port
-			_, err := fmt.Sscanf(cfg.Server.Addr, ":%d", &port)
-			if err != nil {
-				logger.Error("Invalid server address: %s", cfg.Server.Addr)
-				os.Exit(1)
-			}
-		} else {
-			// Host and port
-			_, err := fmt.Sscanf(cfg.Server.Addr, "%[^:]:%d", &host, &port)
-			if err != nil {
-				logger.Error("Invalid server address: %s", cfg.Server.Addr)
-				os.Exit(1)
-			}
-		}
+	// Get default server configuration
+	defaultServerCfg, err := cfg.Servers.GetDefault()
+	if err != nil {
+		logger.Error("Failed to get default server config: %v", err)
+		os.Exit(1)
 	}
 
-	// Add server instance
-	_, err = mgr.Add(server.Config{
-		Name:            "api",
-		Host:            host,
-		Port:            port,
-		Handler:         r,
-		ShutdownTimeout: cfg.Server.ShutdownTimeout,
-		DrainTimeout:    cfg.Server.DrainTimeout,
-		ReadTimeout:     cfg.Server.ReadTimeout,
-		WriteTimeout:    cfg.Server.WriteTimeout,
-		IdleTimeout:     cfg.Server.IdleTimeout,
-	})
+	// Apply global defaults
+	defaultServerCfg.ApplyGlobalDefaults(cfg.Servers)
+
+	// Convert to server.Config and add instance
+	serverCfg := server.FromConfigInstanceToServerConfig(defaultServerCfg, r)
+
+	logger.Info("Configuration loaded - Server '%s' will listen on %s:%d",
+		serverCfg.Name, serverCfg.Host, serverCfg.Port)
+
+	_, err = mgr.Add(serverCfg)
 	if err != nil {
 		logger.Error("Failed to add server: %v", err)
 		os.Exit(1)
 	}
 
 	// Start server with graceful shutdown
-	logger.Info("Starting server on %s", cfg.Server.Addr)
+	logger.Info("Starting server '%s' on %s:%d", serverCfg.Name, serverCfg.Host, serverCfg.Port)
 	if err := mgr.ServeWithGracefulShutdown(); err != nil {
 		logger.Error("Server failed: %v", err)
 		os.Exit(1)

pkg/config/config.go

@@ -4,27 +4,77 @@ import "time"
 
 // Config represents the complete application configuration
 type Config struct {
-	Server        ServerConfig        `mapstructure:"server"`
-	Tracing       TracingConfig       `mapstructure:"tracing"`
-	Cache         CacheConfig         `mapstructure:"cache"`
-	Logger        LoggerConfig        `mapstructure:"logger"`
-	ErrorTracking ErrorTrackingConfig `mapstructure:"error_tracking"`
-	Middleware    MiddlewareConfig    `mapstructure:"middleware"`
-	CORS          CORSConfig          `mapstructure:"cors"`
-	EventBroker   EventBrokerConfig   `mapstructure:"event_broker"`
-	DBManager     DBManagerConfig     `mapstructure:"dbmanager"`
-}
-
-// ServerConfig holds server-related configuration
-type ServerConfig struct {
-	Addr            string        `mapstructure:"addr"`
+	Servers       ServersConfig          `mapstructure:"servers"`
+	Tracing       TracingConfig          `mapstructure:"tracing"`
+	Cache         CacheConfig            `mapstructure:"cache"`
+	Logger        LoggerConfig           `mapstructure:"logger"`
+	ErrorTracking ErrorTrackingConfig    `mapstructure:"error_tracking"`
+	Middleware    MiddlewareConfig       `mapstructure:"middleware"`
+	CORS          CORSConfig             `mapstructure:"cors"`
+	EventBroker   EventBrokerConfig      `mapstructure:"event_broker"`
+	DBManager     DBManagerConfig        `mapstructure:"dbmanager"`
+	Paths         PathsConfig            `mapstructure:"paths"`
+	Extensions    map[string]interface{} `mapstructure:"extensions"`
+}
+
+// ServersConfig contains configuration for the server manager
+type ServersConfig struct {
+	// DefaultServer is the name of the default server to use
+	DefaultServer string `mapstructure:"default_server"`
+
+	// Instances is a map of server name to server configuration
+	Instances map[string]ServerInstanceConfig `mapstructure:"instances"`
+
+	// Global timeout defaults (can be overridden per instance)
 	ShutdownTimeout time.Duration `mapstructure:"shutdown_timeout"`
 	DrainTimeout    time.Duration `mapstructure:"drain_timeout"`
 	ReadTimeout     time.Duration `mapstructure:"read_timeout"`
 	WriteTimeout    time.Duration `mapstructure:"write_timeout"`
 	IdleTimeout     time.Duration `mapstructure:"idle_timeout"`
 }
 
+// ServerInstanceConfig defines configuration for a single server instance
+type ServerInstanceConfig struct {
+	// Name is the unique name of this server instance
+	Name string `mapstructure:"name"`
+
+	// Host is the host to bind to (e.g., "localhost", "0.0.0.0", "")
+	Host string `mapstructure:"host"`
+
+	// Port is the port number to listen on
+	Port int `mapstructure:"port"`
+
+	// Description is a human-readable description of this server
+	Description string `mapstructure:"description"`
+
+	// GZIP enables GZIP compression middleware
+	GZIP bool `mapstructure:"gzip"`
+
+	// TLS/HTTPS configuration options (mutually exclusive)
+	// Option 1: Provide certificate and key files directly
+	SSLCert string `mapstructure:"ssl_cert"`
+	SSLKey  string `mapstructure:"ssl_key"`
+
+	// Option 2: Use self-signed certificate (for development/testing)
+	SelfSignedSSL bool `mapstructure:"self_signed_ssl"`
+
+	// Option 3: Use Let's Encrypt / AutoTLS
+	AutoTLS         bool     `mapstructure:"auto_tls"`
+	AutoTLSDomains  []string `mapstructure:"auto_tls_domains"`
+	AutoTLSCacheDir string   `mapstructure:"auto_tls_cache_dir"`
+	AutoTLSEmail    string   `mapstructure:"auto_tls_email"`
+
+	// Timeout configurations (overrides global defaults)
+	ShutdownTimeout *time.Duration `mapstructure:"shutdown_timeout"`
+	DrainTimeout    *time.Duration `mapstructure:"drain_timeout"`
+	ReadTimeout     *time.Duration `mapstructure:"read_timeout"`
+	WriteTimeout    *time.Duration `mapstructure:"write_timeout"`
+	IdleTimeout     *time.Duration `mapstructure:"idle_timeout"`
+
+	// Tags for organization and filtering
+	Tags map[string]string `mapstructure:"tags"`
+}
+
 // TracingConfig holds OpenTelemetry tracing configuration
 type TracingConfig struct {
 	Enabled        bool   `mapstructure:"enabled"`
@@ -136,3 +186,8 @@ type EventBrokerRetryPolicyConfig struct {
 	MaxDelay      time.Duration `mapstructure:"max_delay"`
 	BackoffFactor float64       `mapstructure:"backoff_factor"`
 }
+
+// PathsConfig contains configuration for named file system paths
+// This is a map of path name to file system path
+// Example: "data_dir": "/var/lib/myapp/data"
+type PathsConfig map[string]string

pkg/config/manager.go

@@ -107,7 +107,7 @@ func (m *Manager) SetConfig(cfg *Config) error {
 	}
 
 	// Use viper's merge to apply the config
-	m.v.Set("server", cfg.Server)
+	m.v.Set("servers", cfg.Servers)
 	m.v.Set("tracing", cfg.Tracing)
 	m.v.Set("cache", cfg.Cache)
 	m.v.Set("logger", cfg.Logger)
@@ -116,6 +116,8 @@ func (m *Manager) SetConfig(cfg *Config) error {
 	m.v.Set("cors", cfg.CORS)
 	m.v.Set("event_broker", cfg.EventBroker)
 	m.v.Set("dbmanager", cfg.DBManager)
+	m.v.Set("paths", cfg.Paths)
+	m.v.Set("extensions", cfg.Extensions)
 
 	return nil
 }
@@ -155,13 +157,22 @@ func (m *Manager) SaveConfig(path string) error {
 
 // setDefaults sets default configuration values
 func setDefaults(v *viper.Viper) {
-	// Server defaults
-	v.SetDefault("server.addr", ":8080")
-	v.SetDefault("server.shutdown_timeout", "30s")
-	v.SetDefault("server.drain_timeout", "25s")
-	v.SetDefault("server.read_timeout", "10s")
-	v.SetDefault("server.write_timeout", "10s")
-	v.SetDefault("server.idle_timeout", "120s")
+	// Server defaults - new structure
+	v.SetDefault("servers.default_server", "default")
+
+	// Global server timeout defaults
+	v.SetDefault("servers.shutdown_timeout", "30s")
+	v.SetDefault("servers.drain_timeout", "25s")
+	v.SetDefault("servers.read_timeout", "10s")
+	v.SetDefault("servers.write_timeout", "10s")
+	v.SetDefault("servers.idle_timeout", "120s")
+
+	// Default server instance
+	v.SetDefault("servers.instances.default.name", "default")
+	v.SetDefault("servers.instances.default.host", "")
+	v.SetDefault("servers.instances.default.port", 8080)
+	v.SetDefault("servers.instances.default.description", "Default HTTP server")
+	v.SetDefault("servers.instances.default.gzip", false)
 
 	// Tracing defaults
 	v.SetDefault("tracing.enabled", false)
@@ -259,4 +270,13 @@ func setDefaults(v *viper.Viper) {
 	v.SetDefault("event_broker.retry_policy.initial_delay", "1s")
 	v.SetDefault("event_broker.retry_policy.max_delay", "30s")
 	v.SetDefault("event_broker.retry_policy.backoff_factor", 2.0)
+
+	// Paths defaults (common directory paths)
+	v.SetDefault("paths.data_dir", "./data")
+	v.SetDefault("paths.config_dir", "./config")
+	v.SetDefault("paths.logs_dir", "./logs")
+	v.SetDefault("paths.temp_dir", "./tmp")
+
+	// Extensions defaults (empty map)
+	v.SetDefault("extensions", map[string]interface{}{})
 }