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>
2026-10-14 04:07:46 +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 +1,455 @@
+package backends
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+// Pure-Go Redis client implementation
+// Compatible with Yaegi interpreter (no unsafe package)
+// Implements RESP protocol for basic Redis operations
+
+var (
+	ErrPoolExhausted = errors.New("connection pool exhausted")
+)
+
+// RedisBackend implements a Redis-based cache backend using pure Go
+type RedisBackend struct {
+	config        *Config
+	pool          *ConnectionPool
+	healthMonitor *HealthMonitor
+
+	// Metrics
+	hits   atomic.Int64
+	misses atomic.Int64
+
+	// Lifecycle
+	closed atomic.Bool
+	mu     sync.Mutex
+}
+
+// NewRedisBackend creates a new Redis cache backend with pure-Go implementation
+func NewRedisBackend(config *Config) (*RedisBackend, error) {
+	if config == nil {
+		return nil, fmt.Errorf("config is required")
+	}
+
+	if config.RedisAddr == "" {
+		return nil, fmt.Errorf("redis address is required")
+	}
+
+	// Create connection pool with health checks enabled
+	poolConfig := &PoolConfig{
+		Address:           config.RedisAddr,
+		Password:          config.RedisPassword,
+		DB:                config.RedisDB,
+		MaxConnections:    config.PoolSize,
+		ConnectTimeout:    5 * time.Second,
+		ReadTimeout:       3 * time.Second,
+		WriteTimeout:      3 * time.Second,
+		EnableHealthCheck: true,
+		MaxRetries:        3,
+		RetryDelay:        100 * time.Millisecond,
+	}
+
+	pool, err := NewConnectionPool(poolConfig)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create connection pool: %w", err)
+	}
+
+	// Create health monitor
+	healthConfig := DefaultHealthMonitorConfig()
+	healthMonitor := NewHealthMonitor(pool, healthConfig)
+
+	backend := &RedisBackend{
+		config:        config,
+		pool:          pool,
+		healthMonitor: healthMonitor,
+	}
+
+	// Test connectivity
+	if err := backend.Ping(context.Background()); err != nil {
+		pool.Close()
+		return nil, fmt.Errorf("failed to ping Redis: %w", err)
+	}
+
+	// Start health monitoring
+	healthMonitor.Start()
+
+	return backend, nil
+}
+
+// Set stores a value in Redis with TTL
+func (r *RedisBackend) Set(ctx context.Context, key string, value []byte, ttl time.Duration) error {
+	if r.closed.Load() {
+		return ErrBackendClosed
+	}
+
+	prefixedKey := r.prefixKey(key)
+
+	// Execute with retry logic
+	return r.executeWithRetry(ctx, func(conn *RedisConn) error {
+		var err error
+
+		// Use PSETEX for millisecond precision, SETEX for second precision
+		if ttl > 0 {
+			ttlMillis := ttl.Milliseconds()
+			if ttlMillis < 1000 {
+				// Use PSETEX for sub-second TTLs (millisecond precision)
+				_, err = conn.Do("PSETEX", prefixedKey, fmt.Sprintf("%d", ttlMillis), string(value))
+			} else {
+				// Use SETEX for larger TTLs (second precision)
+				ttlSeconds := int(ttl.Seconds())
+				_, err = conn.Do("SETEX", prefixedKey, fmt.Sprintf("%d", ttlSeconds), string(value))
+			}
+		} else {
+			_, err = conn.Do("SET", prefixedKey, string(value))
+		}
+
+		return err
+	})
+}
+
+// Get retrieves a value from Redis
+func (r *RedisBackend) Get(ctx context.Context, key string) ([]byte, time.Duration, bool, error) {
+	if r.closed.Load() {
+		return nil, 0, false, ErrBackendClosed
+	}
+
+	prefixedKey := r.prefixKey(key)
+	var resultValue []byte
+	var resultTTL time.Duration
+	var resultExists bool
+
+	// Execute with retry logic
+	err := r.executeWithRetry(ctx, func(conn *RedisConn) error {
+		// Get value
+		resp, err := conn.Do("GET", prefixedKey)
+		if err != nil {
+			if errors.Is(err, ErrNilResponse) {
+				r.misses.Add(1)
+				resultExists = false
+				return nil // Not an error, key just doesn't exist
+			}
+			return err
+		}
+
+		value, err := RESPString(resp)
+		if err != nil {
+			return err
+		}
+
+		// Get TTL
+		ttlResp, err := conn.Do("TTL", prefixedKey)
+		if err != nil {
+			// If TTL fails, still return the value
+			r.hits.Add(1)
+			resultValue = []byte(value)
+			resultTTL = 0
+			resultExists = true
+			return nil
+		}
+
+		ttlSeconds, _ := RESPInt(ttlResp)
+		var ttl time.Duration
+		if ttlSeconds > 0 {
+			ttl = time.Duration(ttlSeconds) * time.Second
+		}
+
+		r.hits.Add(1)
+		resultValue = []byte(value)
+		resultTTL = ttl
+		resultExists = true
+		return nil
+	})
+
+	return resultValue, resultTTL, resultExists, err
+}
+
+// Delete removes a key from Redis
+func (r *RedisBackend) Delete(ctx context.Context, key string) (bool, error) {
+	if r.closed.Load() {
+		return false, ErrBackendClosed
+	}
+
+	conn, err := r.pool.Get(ctx)
+	if err != nil {
+		return false, err
+	}
+	defer r.pool.Put(conn)
+
+	prefixedKey := r.prefixKey(key)
+	resp, err := conn.Do("DEL", prefixedKey)
+	if err != nil {
+		return false, err
+	}
+
+	count, err := RESPInt(resp)
+	if err != nil {
+		return false, err
+	}
+
+	return count > 0, nil
+}
+
+// Exists checks if a key exists in Redis
+func (r *RedisBackend) Exists(ctx context.Context, key string) (bool, error) {
+	if r.closed.Load() {
+		return false, ErrBackendClosed
+	}
+
+	conn, err := r.pool.Get(ctx)
+	if err != nil {
+		return false, err
+	}
+	defer r.pool.Put(conn)
+
+	prefixedKey := r.prefixKey(key)
+	resp, err := conn.Do("EXISTS", prefixedKey)
+	if err != nil {
+		return false, err
+	}
+
+	count, err := RESPInt(resp)
+	if err != nil {
+		return false, err
+	}
+
+	return count > 0, nil
+}
+
+// Clear removes all keys with the configured prefix
+func (r *RedisBackend) Clear(ctx context.Context) error {
+	if r.closed.Load() {
+		return ErrBackendClosed
+	}
+
+	conn, err := r.pool.Get(ctx)
+	if err != nil {
+		return err
+	}
+	defer r.pool.Put(conn)
+
+	// Use FLUSHDB if no prefix (clear entire DB)
+	if r.config.RedisPrefix == "" {
+		_, err := conn.Do("FLUSHDB")
+		return err
+	}
+
+	// With prefix, we need to scan and delete keys
+	// For simplicity in this implementation, we'll use KEYS pattern (not recommended for production at scale)
+	pattern := r.config.RedisPrefix + "*"
+	resp, err := conn.Do("KEYS", pattern)
+	if err != nil {
+		return err
+	}
+
+	// Extract keys from array response
+	keys, ok := resp.([]interface{})
+	if !ok || len(keys) == 0 {
+		return nil
+	}
+
+	// Delete each key
+	for _, keyInterface := range keys {
+		key, err := RESPString(keyInterface)
+		if err != nil {
+			continue
+		}
+		conn.Do("DEL", key) // Best effort, ignore errors
+	}
+
+	return nil
+}
+
+// GetStats returns backend statistics
+func (r *RedisBackend) GetStats() map[string]interface{} {
+	hits := r.hits.Load()
+	misses := r.misses.Load()
+	total := hits + misses
+
+	hitRate := float64(0)
+	if total > 0 {
+		hitRate = float64(hits) / float64(total)
+	}
+
+	stats := map[string]interface{}{
+		"backend":  "redis-pure-go",
+		"address":  r.config.RedisAddr,
+		"hits":     hits,
+		"misses":   misses,
+		"hit_rate": hitRate,
+		"pool":     r.pool.Stats(),
+	}
+
+	// Add health monitor stats if available
+	if r.healthMonitor != nil {
+		stats["health"] = r.healthMonitor.GetStats()
+	}
+
+	return stats
+}
+
+// Ping checks Redis connectivity
+func (r *RedisBackend) Ping(ctx context.Context) error {
+	if r.closed.Load() {
+		return ErrBackendClosed
+	}
+
+	conn, err := r.pool.Get(ctx)
+	if err != nil {
+		return err
+	}
+	defer r.pool.Put(conn)
+
+	_, err = conn.Do("PING")
+	return err
+}
+
+// Close closes the Redis backend and all connections
+func (r *RedisBackend) Close() error {
+	if r.closed.Swap(true) {
+		return nil // Already closed
+	}
+
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	// Stop health monitor
+	if r.healthMonitor != nil {
+		r.healthMonitor.Stop()
+	}
+
+	// Close connection pool
+	if r.pool != nil {
+		return r.pool.Close()
+	}
+
+	return nil
+}
+
+// prefixKey adds the configured prefix to a key
+func (r *RedisBackend) prefixKey(key string) string {
+	if r.config.RedisPrefix == "" {
+		return key
+	}
+	return r.config.RedisPrefix + key
+}
+
+// executeWithRetry executes a Redis operation with exponential backoff retry logic
+func (r *RedisBackend) executeWithRetry(ctx context.Context, operation func(*RedisConn) error) error {
+	maxRetries := 3
+	baseDelay := 100 * time.Millisecond
+
+	for attempt := 0; attempt < maxRetries; attempt++ {
+		conn, err := r.pool.Get(ctx)
+		if err != nil {
+			// If we can't get a connection and this is the last attempt, fail
+			if attempt == maxRetries-1 {
+				return fmt.Errorf("failed to get connection after %d attempts: %w", maxRetries, err)
+			}
+
+			// Wait with exponential backoff before retrying
+			delay := baseDelay * time.Duration(1<<uint(attempt))
+			select {
+			case <-ctx.Done():
+				return ctx.Err()
+			case <-time.After(delay):
+				continue
+			}
+		}
+
+		// Execute the operation
+		err = operation(conn)
+		r.pool.Put(conn)
+
+		// If successful, return
+		if err == nil {
+			return nil
+		}
+
+		// If error is not retryable or last attempt, fail
+		if attempt == maxRetries-1 || !isRetryableError(err) {
+			return err
+		}
+
+		// Wait with exponential backoff before retrying
+		delay := baseDelay * time.Duration(1<<uint(attempt))
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case <-time.After(delay):
+			continue
+		}
+	}
+
+	return fmt.Errorf("operation failed after %d attempts", maxRetries)
+}
+
+// isRetryableError determines if an error is worth retrying
+func isRetryableError(err error) bool {
+	if err == nil {
+		return false
+	}
+
+	// Retry on connection errors, timeouts, etc.
+	// Don't retry on application-level errors like wrong type
+	errMsg := err.Error()
+	retryablePatterns := []string{
+		"connection",
+		"timeout",
+		"EOF",
+		"broken pipe",
+		"reset by peer",
+	}
+
+	for _, pattern := range retryablePatterns {
+		if contains(errMsg, pattern) {
+			return true
+		}
+	}
+
+	return false
+}
+
+// SetMany stores multiple values in Redis (batch operation)
+func (r *RedisBackend) SetMany(ctx context.Context, items map[string][]byte, ttl time.Duration) error {
+	if r.closed.Load() {
+		return ErrBackendClosed
+	}
+
+	// For simplicity, execute sequentially (can be optimized with pipelining later)
+	for key, value := range items {
+		if err := r.Set(ctx, key, value, ttl); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// GetMany retrieves multiple values from Redis
+func (r *RedisBackend) GetMany(ctx context.Context, keys []string) (map[string][]byte, error) {
+	if r.closed.Load() {
+		return nil, ErrBackendClosed
+	}
+
+	result := make(map[string][]byte)
+
+	// For simplicity, execute sequentially
+	for _, key := range keys {
+		value, _, exists, err := r.Get(ctx, key)
+		if err != nil {
+			return nil, err
+		}
+		if exists {
+			result[key] = value
+		}
+	}
+
+	return result, nil
+}