Initial commit: Beszel fork with Domain Locker integration

agent/agent_cache.go

@@ -0,0 +1,55 @@
+package agent
+
+import (
+	"sync"
+	"time"
+
+	"github.com/henrygd/beszel/internal/entities/system"
+)
+
+type systemDataCache struct {
+	sync.RWMutex
+	cache map[uint16]*cacheNode
+}
+
+type cacheNode struct {
+	data       *system.CombinedData
+	lastUpdate time.Time
+}
+
+// NewSystemDataCache creates a cache keyed by the polling interval in milliseconds.
+func NewSystemDataCache() *systemDataCache {
+	return &systemDataCache{
+		cache: make(map[uint16]*cacheNode),
+	}
+}
+
+// Get returns cached combined data when the entry is still considered fresh.
+func (c *systemDataCache) Get(cacheTimeMs uint16) (stats *system.CombinedData, isCached bool) {
+	c.RLock()
+	defer c.RUnlock()
+
+	node, ok := c.cache[cacheTimeMs]
+	if !ok {
+		return &system.CombinedData{}, false
+	}
+	// allowedSkew := time.Second
+	// isFresh := time.Since(node.lastUpdate) < time.Duration(cacheTimeMs)*time.Millisecond-allowedSkew
+	// allow a 50% skew of the cache time
+	isFresh := time.Since(node.lastUpdate) < time.Duration(cacheTimeMs/2)*time.Millisecond
+	return node.data, isFresh
+}
+
+// Set stores the latest combined data snapshot for the given interval.
+func (c *systemDataCache) Set(data *system.CombinedData, cacheTimeMs uint16) {
+	c.Lock()
+	defer c.Unlock()
+
+	node, ok := c.cache[cacheTimeMs]
+	if !ok {
+		node = &cacheNode{}
+		c.cache[cacheTimeMs] = node
+	}
+	node.data = data
+	node.lastUpdate = time.Now()
+}