improvements mid apr 2025 (#26)

* General improvements and bug fixes.
* Admin dashboard

rps_tracker.go

@@ -0,0 +1,89 @@
+package main
+
+import (
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+// RPSTracker tracks requests per second using periodic sampling
+type RPSTracker struct {
+	lastCount      atomic.Int64
+	lastSampleTime atomic.Int64 // Unix nano
+	currentRPS     uint64       // stored as uint64, accessed with atomic operations
+	mu             sync.RWMutex // for currentRPS updates
+}
+
+// NewRPSTracker creates a new RPS tracker
+func NewRPSTracker() *RPSTracker {
+	tracker := &RPSTracker{}
+	tracker.lastSampleTime.Store(time.Now().UnixNano())
+	go tracker.updateLoop()
+	return tracker
+}
+
+// RecordRequest increments the request counter
+func (r *RPSTracker) RecordRequest() {
+	// Just increment the counter, sampling happens in background
+	r.lastCount.Add(1)
+}
+
+// updateLoop periodically calculates current RPS
+func (r *RPSTracker) updateLoop() {
+	ticker := time.NewTicker(1 * time.Second)
+	defer ticker.Stop()
+
+	for range ticker.C {
+		r.sample()
+	}
+}
+
+// sample calculates RPS since last sample
+func (r *RPSTracker) sample() {
+	now := time.Now()
+	nowNano := now.UnixNano()
+
+	currentCount := r.lastCount.Load()
+	lastSampleNano := r.lastSampleTime.Load()
+
+	if lastSampleNano == 0 {
+		r.lastSampleTime.Store(nowNano)
+		return
+	}
+
+	elapsed := float64(nowNano-lastSampleNano) / float64(time.Second)
+	if elapsed > 0 {
+		rps := float64(currentCount) / elapsed
+		// Store RPS as centirps for precision (multiply by 100)
+		r.mu.Lock()
+		atomic.StoreUint64(&r.currentRPS, uint64(rps*100))
+		r.mu.Unlock()
+	}
+
+	// Reset for next sample
+	r.lastCount.Store(0)
+	r.lastSampleTime.Store(nowNano)
+}
+
+// GetCurrentRPS returns the current requests per second
+func (r *RPSTracker) GetCurrentRPS() float64 {
+	r.mu.RLock()
+	centirps := atomic.LoadUint64(&r.currentRPS)
+	r.mu.RUnlock()
+	return float64(centirps) / 100.0
+}
+
+var globalRPSTracker *RPSTracker
+
+// InitializeRPSTracker initializes the global RPS tracker
+func InitializeRPSTracker() *RPSTracker {
+	if globalRPSTracker == nil {
+		globalRPSTracker = NewRPSTracker()
+	}
+	return globalRPSTracker
+}
+
+// GetRPSTracker returns the global RPS tracker
+func GetRPSTracker() *RPSTracker {
+	return globalRPSTracker
+}