refactor(config): replace nonstream-keepalive with nonstream-keepalive-interval

- Updated `SDKConfig` to use `nonstream-keepalive-interval` (seconds) instead of the boolean `nonstream-keepalive`.
- Refactored handlers and logic to incorporate the new interval-based configuration.
- Updated config diff, tests, and example YAML to reflect the changes.

config.example.yaml

@@ -77,8 +77,8 @@ routing:
 # When true, enable authentication for the WebSocket API (/v1/ws).
 ws-auth: false
 
-# When true, emit blank lines every 5s for non-streaming responses to prevent idle timeouts.
+# When > 0, emit blank lines every N seconds for non-streaming responses to prevent idle timeouts.
-nonstream-keepalive: false
+nonstream-keepalive-interval: 0
 
 # Streaming behavior (SSE keep-alives + safe bootstrap retries).
 # streaming:

internal/config/sdk_config.go

@@ -26,8 +26,9 @@ type SDKConfig struct {
 	// Streaming configures server-side streaming behavior (keep-alives and safe bootstrap retries).
 	Streaming StreamingConfig `yaml:"streaming" json:"streaming"`
 
-	// NonStreamKeepAlive enables emitting blank lines every 5 seconds for non-streaming responses.
+	// NonStreamKeepAliveInterval controls how often blank lines are emitted for non-streaming responses.
-	NonStreamKeepAlive bool `yaml:"nonstream-keepalive" json:"nonstream-keepalive"`
+	// <= 0 disables keep-alives. Value is in seconds.
+	NonStreamKeepAliveInterval int `yaml:"nonstream-keepalive-interval,omitempty" json:"nonstream-keepalive-interval,omitempty"`
 }
 
 // StreamingConfig holds server streaming behavior configuration.

internal/watcher/diff/config_diff.go

@@ -54,8 +54,8 @@ func BuildConfigChangeDetails(oldCfg, newCfg *config.Config) []string {
 	if oldCfg.ForceModelPrefix != newCfg.ForceModelPrefix {
 		changes = append(changes, fmt.Sprintf("force-model-prefix: %t -> %t", oldCfg.ForceModelPrefix, newCfg.ForceModelPrefix))
 	}
-	if oldCfg.NonStreamKeepAlive != newCfg.NonStreamKeepAlive {
+	if oldCfg.NonStreamKeepAliveInterval != newCfg.NonStreamKeepAliveInterval {
-		changes = append(changes, fmt.Sprintf("nonstream-keepalive: %t -> %t", oldCfg.NonStreamKeepAlive, newCfg.NonStreamKeepAlive))
+		changes = append(changes, fmt.Sprintf("nonstream-keepalive-interval: %d -> %d", oldCfg.NonStreamKeepAliveInterval, newCfg.NonStreamKeepAliveInterval))
 	}
 
 	// Quota-exceeded behavior

internal/watcher/diff/config_diff_test.go

@@ -235,7 +235,7 @@ func TestBuildConfigChangeDetails_FlagsAndKeys(t *testing.T) {
 			ProxyURL:                   "http://old-proxy",
 			APIKeys:                    []string{"key-1"},
 			ForceModelPrefix:           false,
-			NonStreamKeepAlive: false,
+			NonStreamKeepAliveInterval: 0,
 		},
 	}
 	newCfg := &config.Config{
@@ -272,7 +272,7 @@ func TestBuildConfigChangeDetails_FlagsAndKeys(t *testing.T) {
 			ProxyURL:                   "http://new-proxy",
 			APIKeys:                    []string{" key-1 ", "key-2"},
 			ForceModelPrefix:           true,
-			NonStreamKeepAlive: true,
+			NonStreamKeepAliveInterval: 5,
 		},
 	}
 
@@ -287,7 +287,7 @@ func TestBuildConfigChangeDetails_FlagsAndKeys(t *testing.T) {
 	expectContains(t, details, "proxy-url: http://old-proxy -> http://new-proxy")
 	expectContains(t, details, "ws-auth: false -> true")
 	expectContains(t, details, "force-model-prefix: false -> true")
-	expectContains(t, details, "nonstream-keepalive: false -> true")
+	expectContains(t, details, "nonstream-keepalive-interval: 0 -> 5")
 	expectContains(t, details, "quota-exceeded.switch-project: false -> true")
 	expectContains(t, details, "quota-exceeded.switch-preview-model: false -> true")
 	expectContains(t, details, "api-keys count: 1 -> 2")

sdk/api/handlers/handlers.go

@@ -49,7 +49,6 @@ const idempotencyKeyMetadataKey = "idempotency_key"
 const (
 	defaultStreamingKeepAliveSeconds = 0
 	defaultStreamingBootstrapRetries = 0
-	nonStreamingKeepAliveInterval    = 5 * time.Second
 )
 
 // BuildErrorResponseBody builds an OpenAI-compatible JSON error response body.
@@ -115,6 +114,19 @@ func StreamingKeepAliveInterval(cfg *config.SDKConfig) time.Duration {
 	return time.Duration(seconds) * time.Second
 }
 
+// NonStreamingKeepAliveInterval returns the keep-alive interval for non-streaming responses.
+// Returning 0 disables keep-alives (default when unset).
+func NonStreamingKeepAliveInterval(cfg *config.SDKConfig) time.Duration {
+	seconds := 0
+	if cfg != nil {
+		seconds = cfg.NonStreamKeepAliveInterval
+	}
+	if seconds <= 0 {
+		return 0
+	}
+	return time.Duration(seconds) * time.Second
+}
+
 // StreamingBootstrapRetries returns how many times a streaming request may be retried before any bytes are sent.
 func StreamingBootstrapRetries(cfg *config.SDKConfig) int {
 	retries := defaultStreamingBootstrapRetries
@@ -298,10 +310,11 @@ func (h *BaseAPIHandler) GetContextWithCancel(handler interfaces.APIHandler, c *
 // StartNonStreamingKeepAlive emits blank lines every 5 seconds while waiting for a non-streaming response.
 // It returns a stop function that must be called before writing the final response.
 func (h *BaseAPIHandler) StartNonStreamingKeepAlive(c *gin.Context, ctx context.Context) func() {
-	if h == nil || h.Cfg == nil || !h.Cfg.NonStreamKeepAlive {
+	if h == nil || c == nil {
 		return func() {}
 	}
-	if c == nil {
+	interval := NonStreamingKeepAliveInterval(h.Cfg)
+	if interval <= 0 {
 		return func() {}
 	}
 	flusher, ok := c.Writer.(http.Flusher)
@@ -318,7 +331,7 @@ func (h *BaseAPIHandler) StartNonStreamingKeepAlive(c *gin.Context, ctx context.
 	wg.Add(1)
 	go func() {
 		defer wg.Done()
-		ticker := time.NewTicker(nonStreamingKeepAliveInterval)
+		ticker := time.NewTicker(interval)
 		defer ticker.Stop()
 		for {
 			select {