feature: mqtt support

pkg/mqttspec/config.go

@@ -0,0 +1,178 @@
+package mqttspec
+
+import (
+	"crypto/tls"
+	"time"
+)
+
+// BrokerMode specifies how to connect to MQTT
+type BrokerMode string
+
+const (
+	// BrokerModeEmbedded runs Mochi MQTT broker in-process
+	BrokerModeEmbedded BrokerMode = "embedded"
+	// BrokerModeExternal connects to external MQTT broker as client
+	BrokerModeExternal BrokerMode = "external"
+)
+
+// Config holds all mqttspec configuration
+type Config struct {
+	// BrokerMode determines whether to use embedded or external broker
+	BrokerMode BrokerMode
+
+	// Broker configuration for embedded mode
+	Broker BrokerConfig
+
+	// ExternalBroker configuration for external client mode
+	ExternalBroker ExternalBrokerConfig
+
+	// Topics configuration
+	Topics TopicConfig
+
+	// QoS configuration for different message types
+	QoS QoSConfig
+
+	// Auth configuration
+	Auth AuthConfig
+
+	// Timeouts for various operations
+	Timeouts TimeoutConfig
+}
+
+// BrokerConfig configures the embedded Mochi MQTT broker
+type BrokerConfig struct {
+	// Host to bind to (default: "localhost")
+	Host string
+
+	// Port to listen on (default: 1883)
+	Port int
+
+	// EnableWebSocket enables WebSocket support
+	EnableWebSocket bool
+
+	// WSPort is the WebSocket port (default: 8883)
+	WSPort int
+
+	// MaxConnections limits concurrent client connections
+	MaxConnections int
+
+	// KeepAlive is the client keepalive interval
+	KeepAlive time.Duration
+
+	// EnableAuth enables username/password authentication
+	EnableAuth bool
+}
+
+// ExternalBrokerConfig for connecting as a client to external broker
+type ExternalBrokerConfig struct {
+	// BrokerURL is the broker address (e.g., tcp://host:port or ssl://host:port)
+	BrokerURL string
+
+	// ClientID is a unique identifier for this handler instance
+	ClientID string
+
+	// Username for MQTT authentication
+	Username string
+
+	// Password for MQTT authentication
+	Password string
+
+	// CleanSession flag (default: true)
+	CleanSession bool
+
+	// KeepAlive interval (default: 60s)
+	KeepAlive time.Duration
+
+	// ConnectTimeout for initial connection (default: 30s)
+	ConnectTimeout time.Duration
+
+	// ReconnectDelay between reconnection attempts (default: 5s)
+	ReconnectDelay time.Duration
+
+	// MaxReconnect attempts (0 = unlimited, default: 0)
+	MaxReconnect int
+
+	// TLSConfig for SSL/TLS connections
+	TLSConfig *tls.Config
+}
+
+// TopicConfig defines the MQTT topic structure
+type TopicConfig struct {
+	// Prefix for all topics (default: "spec")
+	// Topics will be: {Prefix}/{client_id}/request|response|notify/{sub_id}
+	Prefix string
+}
+
+// QoSConfig defines quality of service levels for different message types
+type QoSConfig struct {
+	// Request messages QoS (default: 1 - at-least-once)
+	Request byte
+
+	// Response messages QoS (default: 1 - at-least-once)
+	Response byte
+
+	// Notification messages QoS (default: 1 - at-least-once)
+	Notification byte
+}
+
+// AuthConfig for MQTT-level authentication
+type AuthConfig struct {
+	// ValidateCredentials is called to validate username/password for embedded broker
+	// Return true if credentials are valid, false otherwise
+	ValidateCredentials func(username, password string) bool
+}
+
+// TimeoutConfig defines timeouts for various operations
+type TimeoutConfig struct {
+	// Connect timeout for MQTT connection (default: 30s)
+	Connect time.Duration
+
+	// Publish timeout for publishing messages (default: 5s)
+	Publish time.Duration
+
+	// Disconnect timeout for graceful shutdown (default: 10s)
+	Disconnect time.Duration
+}
+
+// DefaultConfig returns a configuration with sensible defaults
+func DefaultConfig() *Config {
+	return &Config{
+		BrokerMode: BrokerModeEmbedded,
+		Broker: BrokerConfig{
+			Host:            "localhost",
+			Port:            1883,
+			EnableWebSocket: false,
+			WSPort:          8883,
+			MaxConnections:  1000,
+			KeepAlive:       60 * time.Second,
+			EnableAuth:      false,
+		},
+		ExternalBroker: ExternalBrokerConfig{
+			BrokerURL:      "",
+			ClientID:       "",
+			Username:       "",
+			Password:       "",
+			CleanSession:   true,
+			KeepAlive:      60 * time.Second,
+			ConnectTimeout: 30 * time.Second,
+			ReconnectDelay: 5 * time.Second,
+			MaxReconnect:   0, // Unlimited
+		},
+		Topics: TopicConfig{
+			Prefix: "spec",
+		},
+		QoS: QoSConfig{
+			Request:      1, // At-least-once
+			Response:     1, // At-least-once
+			Notification: 1, // At-least-once
+		},
+		Auth: AuthConfig{
+			ValidateCredentials: nil,
+		},
+		Timeouts: TimeoutConfig{
+			Connect:    30 * time.Second,
+			Publish:    5 * time.Second,
+			Disconnect: 10 * time.Second,
+		},
+	}
+}