[config] configurable SSE keep-alive period

internal/config/config.go

@@ -13,6 +13,7 @@ type Config struct {
 	Database Database  `yaml:"database"` // database config
 	FCM      FCMConfig `yaml:"fcm"`      // firebase cloud messaging config
 	Tasks    Tasks     `yaml:"tasks"`    // tasks config
+	SSE      SSE       `yaml:"sse"`      // server-sent events config
 }
 
 type Gateway struct {
@@ -53,6 +54,10 @@ type HashingTask struct {
 	IntervalSeconds uint16 `yaml:"interval_seconds" envconfig:"TASKS__HASHING__INTERVAL_SECONDS"` // hashing interval in seconds
 }
 
+type SSE struct {
+	KeepAlivePeriodSeconds uint16 `yaml:"keep_alive_period_seconds" envconfig:"SSE__KEEP_ALIVE_PERIOD_SECONDS"` // keep alive period in seconds, 0 for no keep alive
+}
+
 var defaultConfig = Config{
 	Gateway: Gateway{Mode: GatewayModePublic},
 	HTTP: HTTP{
@@ -75,4 +80,7 @@ var defaultConfig = Config{
 			IntervalSeconds: uint16(15 * 60),
 		},
 	},
+	SSE: SSE{
+		KeepAlivePeriodSeconds: 15,
+	},
 }

internal/config/module.go

@@ -93,6 +93,8 @@ var Module = fx.Module(
 		}
 	}),
 	fx.Provide(func(cfg Config) sse.Config {
-		return sse.NewConfig()
+		return sse.NewConfig(
+			sse.WithKeepAlivePeriod(time.Duration(cfg.SSE.KeepAlivePeriodSeconds) * time.Second),
+		)
 	}),
 )

internal/sms-gateway/modules/sse/config.go

@@ -2,28 +2,38 @@ package sse
 
 import "time"
 
-const defaultKeepAlivePeriod = 15 * time.Second
+type configOption func(*Config)
 
 type Config struct {
 	keepAlivePeriod time.Duration
 }
 
-func NewConfig() Config {
-	return Config{
-		keepAlivePeriod: defaultKeepAlivePeriod,
+const defaultKeepAlivePeriod = 15 * time.Second
+
+var defaultConfig = Config{
+	keepAlivePeriod: defaultKeepAlivePeriod,
+}
+
+func NewConfig(opts ...configOption) Config {
+	c := defaultConfig
+
+	for _, opt := range opts {
+		opt(&c)
 	}
+
+	return c
 }
 
 func (c *Config) KeepAlivePeriod() time.Duration {
 	return c.keepAlivePeriod
 }
 
-func (c *Config) SetKeepAlivePeriod(d time.Duration) *Config {
-	if d <= 0 {
+func WithKeepAlivePeriod(d time.Duration) configOption {
+	if d < 0 {
 		d = defaultKeepAlivePeriod
 	}
 
-	c.keepAlivePeriod = d
-
-	return c
+	return func(c *Config) {
+		c.keepAlivePeriod = d
+	}
 }

internal/sms-gateway/modules/sse/service.go

@@ -101,17 +101,13 @@ func (s *Service) Handler(deviceID string, c *fiber.Ctx) error {
 		conn := s.registerConnection(deviceID)
 		defer s.removeConnection(deviceID, conn.id)
 
-		if err := s.writeToStream(w, ":keepalive"); err != nil {
-			s.logger.Warn("Failed to write keepalive",
-				zap.String("device_id", deviceID),
-				zap.String("connection_id", conn.id),
-				zap.Error(err))
-			return
+		// Conditionally create ticker
+		var ticker *time.Ticker
+		if s.config.keepAlivePeriod > 0 {
+			ticker = time.NewTicker(s.config.keepAlivePeriod)
+			defer ticker.Stop()
 		}
 
-		ticker := time.NewTicker(s.config.keepAlivePeriod)
-		defer ticker.Stop()
-
 		for {
 			select {
 			case event := <-conn.channel:
@@ -122,7 +118,14 @@ func (s *Service) Handler(deviceID string, c *fiber.Ctx) error {
 						zap.Error(err))
 					return
 				}
-			case <-ticker.C:
+			// Conditionally handle ticker events
+			case <-func() <-chan time.Time {
+				if ticker != nil {
+					return ticker.C
+				}
+				// Return nil channel that never fires when disabled
+				return make(chan time.Time)
+			}():
 				if err := s.writeToStream(w, ":keepalive"); err != nil {
 					s.logger.Warn("Failed to write keepalive",
 						zap.String("device_id", deviceID),