chore: sync local updates

mengyamonitor-backend-server/internal/hub/hub.go

@@ -0,0 +1,108 @@
+package hub
+
+import (
+	"encoding/json"
+	"sync"
+	"time"
+
+	"github.com/gorilla/websocket"
+)
+
+// WSMessage is sent to browsers (matches frontend ServerStatus shape).
+type WSMessage struct {
+	Type string                       `json:"type"`
+	Data map[string]json.RawMessage `json:"data"`
+}
+
+type Hub struct {
+	mu sync.RWMutex
+	// serverId -> latest metrics JSON object (not wrapped)
+	metrics map[string]json.RawMessage
+
+	subsMu sync.Mutex
+	// subscribers for broadcast
+	conns map[*websocket.Conn]struct{}
+}
+
+func New() *Hub {
+	return &Hub{
+		metrics: make(map[string]json.RawMessage),
+		conns:   make(map[*websocket.Conn]struct{}),
+	}
+}
+
+func (h *Hub) SetMetrics(serverID string, metricsJSON []byte) {
+	h.mu.Lock()
+	if len(metricsJSON) == 0 {
+		delete(h.metrics, serverID)
+	} else {
+		h.metrics[serverID] = json.RawMessage(append([]byte(nil), metricsJSON...))
+	}
+	h.mu.Unlock()
+}
+
+func (h *Hub) snapshotData() map[string]json.RawMessage {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	out := make(map[string]json.RawMessage, len(h.metrics))
+	now := time.Now().UnixMilli()
+	for id, raw := range h.metrics {
+		// Wrap as ServerStatus for frontend compatibility
+		wrap := map[string]any{
+			"serverId":   id,
+			"online":     true,
+			"metrics":    json.RawMessage(raw),
+			"lastUpdate": now,
+		}
+		b, err := json.Marshal(wrap)
+		if err != nil {
+			continue
+		}
+		out[id] = b
+	}
+	return out
+}
+
+func (h *Hub) BuildSnapshotMessage() ([]byte, error) {
+	msg := WSMessage{
+		Type: "snapshot",
+		Data: h.snapshotData(),
+	}
+	return json.Marshal(msg)
+}
+
+// AddSubscriber registers for broadcast fan-out (call after sending the initial snapshot).
+func (h *Hub) AddSubscriber(c *websocket.Conn) {
+	h.subsMu.Lock()
+	h.conns[c] = struct{}{}
+	h.subsMu.Unlock()
+}
+
+func (h *Hub) Unregister(c *websocket.Conn) {
+	h.subsMu.Lock()
+	delete(h.conns, c)
+	h.subsMu.Unlock()
+}
+
+// BroadcastSnapshot pushes full snapshot to all subscribers.
+func (h *Hub) BroadcastSnapshot() {
+	body, err := h.BuildSnapshotMessage()
+	if err != nil {
+		return
+	}
+	h.subsMu.Lock()
+	defer h.subsMu.Unlock()
+	for c := range h.conns {
+		_ = c.SetWriteDeadline(time.Now().Add(10 * time.Second))
+		if err := c.WriteMessage(websocket.TextMessage, body); err != nil {
+			_ = c.Close()
+			delete(h.conns, c)
+		}
+	}
+}
+
+// NotifyMetricsUpdate should be called after SetMetrics to push to browsers.
+func (h *Hub) NotifyMetricsUpdate(serverID string, metricsJSON []byte) {
+	h.SetMetrics(serverID, metricsJSON)
+	h.BroadcastSnapshot()
+}