Add redis support for distributed caching (#83)

* Add redis support for distributed caching * Move towards the self-provided Redis connection pool and RESP protocol implementation. Official redis client library won't work with yaegi. * fixup! Move towards the self-provided Redis connection pool and RESP protocol implementation. Official redis client library won't work with yaegi. * fixup! fixup! Move towards the self-provided Redis connection pool and RESP protocol implementation. Official redis client library won't work with yaegi. * fixup! fixup! fixup! Move towards the self-provided Redis connection pool and RESP protocol implementation. Official redis client library won't work with yaegi. * fixup! fixup! fixup! fixup! Move towards the self-provided Redis connection pool and RESP protocol implementation. Official redis client library won't work with yaegi. * fixup! fixup! fixup! fixup! fixup! Move towards the self-provided Redis connection pool and RESP protocol implementation. Official redis client library won't work with yaegi. * ... and another all nighter. * fixup! ... and another all nighter. * fixup! fixup! ... and another all nighter. * fixup! fixup! fixup! ... and another all nighter. * Resolve issue #85 by adding ability to set custom claims in JWT tokens * Remove redundant validation in auth middleware ( issue #89 ) * Add ability to set cookie prefix for session cookies ( #87 ) * fixup! Add ability to set cookie prefix for session cookies ( #87 ) * Add ability to set cookie max age - issue #91 * Potential fix for code scanning alert no. 10: Size computation for allocation may overflow Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com> * fixup! Merge main into 0.8.0-redis: resolve conflicts --------- Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>
2026-10-19 04:47:48 +00:00 · 2025-11-30 02:18:46 +00:00
parent 5fcbd54955
commit e64fc7f730
318 changed files with 100989 additions and 948 deletions
@@ -0,0 +1,375 @@
+// Package resilience provides resilience patterns for cache backends.
+package resilience
+
+import (
+	"context"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+// HealthStatus represents the health status of a backend
+type HealthStatus int32
+
+const (
+	// HealthUnknown indicates unknown health status
+	HealthUnknown HealthStatus = iota
+
+	// HealthHealthy indicates the backend is healthy
+	HealthHealthy
+
+	// HealthDegraded indicates the backend is degraded but operational
+	HealthDegraded
+
+	// HealthUnhealthy indicates the backend is unhealthy
+	HealthUnhealthy
+)
+
+// String returns the string representation of the health status
+func (h HealthStatus) String() string {
+	switch h {
+	case HealthHealthy:
+		return "healthy"
+	case HealthDegraded:
+		return "degraded"
+	case HealthUnhealthy:
+		return "unhealthy"
+	default:
+		return "unknown"
+	}
+}
+
+// HealthCheckConfig holds configuration for the health checker
+type HealthCheckConfig struct {
+	// CheckInterval is how often to check health
+	CheckInterval time.Duration
+
+	// Timeout is the timeout for each health check
+	Timeout time.Duration
+
+	// HealthyThreshold is the number of consecutive successes to become healthy
+	HealthyThreshold int
+
+	// UnhealthyThreshold is the number of consecutive failures to become unhealthy
+	UnhealthyThreshold int
+
+	// DegradedThreshold is the latency threshold in ms to mark as degraded
+	DegradedThreshold time.Duration
+
+	// OnStatusChange is called when health status changes
+	OnStatusChange func(from, to HealthStatus)
+
+	// CheckFunc is the function to check health
+	CheckFunc func(ctx context.Context) error
+}
+
+// DefaultHealthCheckConfig returns default configuration
+func DefaultHealthCheckConfig() *HealthCheckConfig {
+	return &HealthCheckConfig{
+		CheckInterval:      30 * time.Second,
+		Timeout:            5 * time.Second,
+		HealthyThreshold:   3,
+		UnhealthyThreshold: 3,
+		DegradedThreshold:  100 * time.Millisecond,
+	}
+}
+
+// HealthChecker monitors the health of a backend
+type HealthChecker struct {
+	config *HealthCheckConfig
+
+	// Status tracking
+	status               atomic.Int32
+	consecutiveSuccesses atomic.Int32
+	consecutiveFailures  atomic.Int32
+
+	// Timing
+	lastCheckTime   time.Time
+	lastSuccessTime time.Time
+	lastFailureTime time.Time
+	averageLatency  atomic.Int64
+	timeMu          sync.RWMutex
+
+	// Metrics
+	totalChecks    atomic.Int64
+	totalSuccesses atomic.Int64
+	totalFailures  atomic.Int64
+	statusChanges  atomic.Int64
+
+	// Lifecycle
+	ticker   *time.Ticker
+	stopChan chan struct{}
+	stopped  atomic.Bool
+	wg       sync.WaitGroup
+}
+
+// NewHealthChecker creates a new health checker
+func NewHealthChecker(config *HealthCheckConfig) *HealthChecker {
+	if config == nil {
+		config = DefaultHealthCheckConfig()
+	}
+
+	hc := &HealthChecker{
+		config:   config,
+		stopChan: make(chan struct{}),
+	}
+	hc.status.Store(int32(HealthUnknown))
+
+	return hc
+}
+
+// Start begins health checking
+func (hc *HealthChecker) Start() {
+	if hc.stopped.Load() {
+		return
+	}
+
+	hc.ticker = time.NewTicker(hc.config.CheckInterval)
+	hc.wg.Add(1)
+	go hc.checkLoop()
+}
+
+// Stop stops health checking
+func (hc *HealthChecker) Stop() {
+	if hc.stopped.Swap(true) {
+		return // Already stopped
+	}
+
+	close(hc.stopChan)
+	if hc.ticker != nil {
+		hc.ticker.Stop()
+	}
+	hc.wg.Wait()
+}
+
+// checkLoop runs periodic health checks
+func (hc *HealthChecker) checkLoop() {
+	defer hc.wg.Done()
+
+	// Initial check - log error but continue
+	if err := hc.Check(context.Background()); err != nil {
+		// Error is already tracked in Check() method, no need to log again
+		_ = err
+	}
+
+	for {
+		select {
+		case <-hc.stopChan:
+			return
+		case <-hc.ticker.C:
+			ctx, cancel := context.WithTimeout(context.Background(), hc.config.Timeout)
+			if err := hc.Check(ctx); err != nil {
+				// Error is already tracked in Check() method, no need to log again
+				_ = err
+			}
+			cancel()
+		}
+	}
+}
+
+// Check performs a health check
+func (hc *HealthChecker) Check(ctx context.Context) error {
+	if hc.config.CheckFunc == nil {
+		return nil
+	}
+
+	hc.totalChecks.Add(1)
+	start := time.Now()
+
+	// Create timeout context if not already set
+	if _, hasDeadline := ctx.Deadline(); !hasDeadline {
+		var cancel context.CancelFunc
+		ctx, cancel = context.WithTimeout(ctx, hc.config.Timeout)
+		defer cancel()
+	}
+
+	// Perform health check
+	err := hc.config.CheckFunc(ctx)
+	latency := time.Since(start)
+
+	hc.timeMu.Lock()
+	hc.lastCheckTime = time.Now()
+	hc.timeMu.Unlock()
+
+	// Update average latency
+	hc.updateAverageLatency(latency)
+
+	if err != nil {
+		hc.recordFailure()
+	} else {
+		hc.recordSuccess(latency)
+	}
+
+	return err
+}
+
+// recordSuccess records a successful health check
+func (hc *HealthChecker) recordSuccess(latency time.Duration) {
+	hc.totalSuccesses.Add(1)
+	successes := hc.consecutiveSuccesses.Add(1)
+	hc.consecutiveFailures.Store(0)
+
+	hc.timeMu.Lock()
+	hc.lastSuccessTime = time.Now()
+	hc.timeMu.Unlock()
+
+	currentStatus := hc.GetStatus()
+	newStatus := currentStatus
+
+	// Check if we should become healthy
+	if successes >= int32(hc.config.HealthyThreshold) {
+		if latency > hc.config.DegradedThreshold {
+			newStatus = HealthDegraded
+		} else {
+			newStatus = HealthHealthy
+		}
+	}
+
+	if newStatus != currentStatus {
+		hc.setStatus(newStatus)
+	}
+}
+
+// recordFailure records a failed health check
+func (hc *HealthChecker) recordFailure() {
+	hc.totalFailures.Add(1)
+	failures := hc.consecutiveFailures.Add(1)
+	hc.consecutiveSuccesses.Store(0)
+
+	hc.timeMu.Lock()
+	hc.lastFailureTime = time.Now()
+	hc.timeMu.Unlock()
+
+	// Check if we should become unhealthy
+	if failures >= int32(hc.config.UnhealthyThreshold) {
+		hc.setStatus(HealthUnhealthy)
+	}
+}
+
+// updateAverageLatency updates the rolling average latency
+func (hc *HealthChecker) updateAverageLatency(latency time.Duration) {
+	// Simple exponential moving average
+	currentAvg := time.Duration(hc.averageLatency.Load())
+	if currentAvg == 0 {
+		hc.averageLatency.Store(int64(latency))
+	} else {
+		// Weight: 0.2 for new value, 0.8 for old average
+		newAvg := (currentAvg*4 + latency) / 5
+		hc.averageLatency.Store(int64(newAvg))
+	}
+}
+
+// GetStatus returns the current health status
+func (hc *HealthChecker) GetStatus() HealthStatus {
+	return HealthStatus(hc.status.Load())
+}
+
+// setStatus changes the health status
+func (hc *HealthChecker) setStatus(newStatus HealthStatus) {
+	oldStatus := HealthStatus(hc.status.Swap(int32(newStatus)))
+
+	if oldStatus != newStatus {
+		hc.statusChanges.Add(1)
+		if hc.config.OnStatusChange != nil {
+			hc.config.OnStatusChange(oldStatus, newStatus)
+		}
+	}
+}
+
+// IsHealthy returns true if the backend is healthy or degraded
+func (hc *HealthChecker) IsHealthy() bool {
+	status := hc.GetStatus()
+	return status == HealthHealthy || status == HealthDegraded
+}
+
+// LastCheckTime returns the time of the last health check
+func (hc *HealthChecker) LastCheckTime() time.Time {
+	hc.timeMu.RLock()
+	defer hc.timeMu.RUnlock()
+	return hc.lastCheckTime
+}
+
+// HealthScore returns a health score between 0.0 (unhealthy) and 1.0 (healthy)
+func (hc *HealthChecker) HealthScore() float64 {
+	status := hc.GetStatus()
+	switch status {
+	case HealthHealthy:
+		return 1.0
+	case HealthDegraded:
+		return 0.7
+	case HealthUnhealthy:
+		return 0.0
+	default:
+		return 0.5
+	}
+}
+
+// Stats returns health checker statistics
+func (hc *HealthChecker) Stats() HealthCheckerStats {
+	hc.timeMu.RLock()
+	lastCheck := hc.lastCheckTime
+	lastSuccess := hc.lastSuccessTime
+	lastFailure := hc.lastFailureTime
+	hc.timeMu.RUnlock()
+
+	totalChecks := hc.totalChecks.Load()
+	totalSuccesses := hc.totalSuccesses.Load()
+	totalFailures := hc.totalFailures.Load()
+
+	successRate := float64(0)
+	if totalChecks > 0 {
+		successRate = float64(totalSuccesses) / float64(totalChecks)
+	}
+
+	return HealthCheckerStats{
+		Status:               hc.GetStatus(),
+		ConsecutiveSuccesses: hc.consecutiveSuccesses.Load(),
+		ConsecutiveFailures:  hc.consecutiveFailures.Load(),
+		TotalChecks:          totalChecks,
+		TotalSuccesses:       totalSuccesses,
+		TotalFailures:        totalFailures,
+		SuccessRate:          successRate,
+		AverageLatency:       time.Duration(hc.averageLatency.Load()),
+		StatusChanges:        hc.statusChanges.Load(),
+		LastCheckTime:        lastCheck,
+		LastSuccessTime:      lastSuccess,
+		LastFailureTime:      lastFailure,
+		HealthScore:          hc.HealthScore(),
+	}
+}
+
+// HealthCheckerStats holds statistics for the health checker
+type HealthCheckerStats struct {
+	Status               HealthStatus
+	ConsecutiveSuccesses int32
+	ConsecutiveFailures  int32
+	TotalChecks          int64
+	TotalSuccesses       int64
+	TotalFailures        int64
+	SuccessRate          float64
+	AverageLatency       time.Duration
+	StatusChanges        int64
+	LastCheckTime        time.Time
+	LastSuccessTime      time.Time
+	LastFailureTime      time.Time
+	HealthScore          float64
+}
+
+// Reset resets the health checker statistics
+func (hc *HealthChecker) Reset() {
+	hc.status.Store(int32(HealthUnknown))
+	hc.consecutiveSuccesses.Store(0)
+	hc.consecutiveFailures.Store(0)
+	hc.totalChecks.Store(0)
+	hc.totalSuccesses.Store(0)
+	hc.totalFailures.Store(0)
+	hc.statusChanges.Store(0)
+	hc.averageLatency.Store(0)
+
+	now := time.Now()
+	hc.timeMu.Lock()
+	hc.lastCheckTime = now
+	hc.lastSuccessTime = now
+	hc.lastFailureTime = now
+	hc.timeMu.Unlock()
+}