feat: complete 2.0.7.12 platform overhaul

server/unified-management/internal/web/dashboard_cache.go

@@ -0,0 +1,85 @@
+package web
+
+import (
+	"sync"
+	"time"
+)
+
+type dashboardCacheEntry struct {
+	value     map[string]any
+	expiresAt time.Time
+	building  chan struct{}
+}
+
+type dashboardSnapshotCache struct {
+	mu         sync.Mutex
+	ttl        time.Duration
+	generation uint64
+	entries    map[string]*dashboardCacheEntry
+}
+
+func newDashboardSnapshotCache(ttl time.Duration) *dashboardSnapshotCache {
+	if ttl <= 0 {
+		ttl = 5 * time.Second
+	}
+	return &dashboardSnapshotCache{ttl: ttl, entries: map[string]*dashboardCacheEntry{}}
+}
+
+func (c *dashboardSnapshotCache) Get(key string, build func() (map[string]any, error)) (map[string]any, bool, error) {
+	for {
+		now := time.Now()
+		c.mu.Lock()
+		entry := c.entries[key]
+		if entry != nil && entry.value != nil && now.Before(entry.expiresAt) {
+			value := entry.value
+			c.mu.Unlock()
+			return value, true, nil
+		}
+		if entry != nil && entry.building != nil {
+			ready := entry.building
+			c.mu.Unlock()
+			<-ready
+			continue
+		}
+		generation := c.generation
+		ready := make(chan struct{})
+		c.entries[key] = &dashboardCacheEntry{building: ready}
+		c.mu.Unlock()
+
+		value, err := build()
+
+		c.mu.Lock()
+		if generation != c.generation {
+			if current := c.entries[key]; current != nil && current.building == ready {
+				delete(c.entries, key)
+			}
+			close(ready)
+			c.mu.Unlock()
+			if err != nil {
+				return nil, false, err
+			}
+			continue
+		}
+		if err != nil {
+			delete(c.entries, key)
+			close(ready)
+			c.mu.Unlock()
+			return nil, false, err
+		}
+		c.entries[key] = &dashboardCacheEntry{value: value, expiresAt: time.Now().Add(c.ttl)}
+		close(ready)
+		c.mu.Unlock()
+		return value, false, nil
+	}
+}
+
+func (c *dashboardSnapshotCache) Invalidate() {
+	c.mu.Lock()
+	c.generation++
+	for key, entry := range c.entries {
+		if entry.building == nil {
+			delete(c.entries, key)
+		}
+	}
+	c.mu.Unlock()
+}