feat: add healthcheck

Author: arturmon

cache.go

@@ -3,6 +3,7 @@ package multi_tier_caching
 import (
 	"context"
 	"errors"
+	"fmt"
 	"time"
 )
 
@@ -133,3 +134,21 @@ func containsLayer(layers []CacheLayer, target CacheLayer) bool {
 	}
 	return false
 }
+
+func (c *MultiTierCache) HealthCheck(ctx context.Context) error {
+	// Checking all cache layers
+	for _, layer := range c.layers {
+		if err := layer.CheckHealth(ctx); err != nil {
+			return fmt.Errorf("cache layer error: %w", err)
+		}
+	}
+
+	// Database check
+	if db, ok := c.db.(HealthChecker); ok {
+		if err := db.CheckHealth(ctx); err != nil {
+			return fmt.Errorf("database error: %w", err)
+		}
+	}
+
+	return nil
+}

database.go

@@ -41,3 +41,7 @@ func (d *DatabaseCache) Delete(ctx context.Context, key string) {
 		return
 	}
 }
+
+func (d *DatabaseCache) CheckHealth(ctx context.Context) error {
+	return d.storage.CheckHealth(ctx)
+}

memory_cache.go

@@ -48,3 +48,7 @@ func (m *MemoryCache) Set(ctx context.Context, key string, value string, ttl tim
 func (m *MemoryCache) Delete(ctx context.Context, key string) {
 	m.storage.Delete(ctx, key)
 }
+
+func (r *MemoryCache) CheckHealth(ctx context.Context) error {
+	return r.storage.CheckHealth(ctx)
+}

memory_cache_test.go

@@ -34,3 +34,7 @@ func (r *RedisCache) Set(ctx context.Context, key string, value string, ttl time
 func (r *RedisCache) Delete(ctx context.Context, key string) {
 	r.storage.Delete(ctx, key)
 }
+
+func (r *RedisCache) CheckHealth(ctx context.Context) error {
+	return r.storage.CheckHealth(ctx)
+}

redis.go

@@ -10,10 +10,15 @@ type CacheLayer interface {
 	Get(ctx context.Context, key string) (string, error)
 	Set(ctx context.Context, key string, value string, ttl time.Duration) error
 	Delete(ctx context.Context, key string)
+	HealthChecker
 }
 
 // Database — interface for working with the database
 type Database interface {
 	Get(ctx context.Context, key string) (string, error)
 	Set(ctx context.Context, key, value string, ttl time.Duration) error
 }
+
+type HealthChecker interface {
+	CheckHealth(ctx context.Context) error
+}

repository.go

@@ -102,3 +102,12 @@ func (d *DatabaseStorage) DeleteCache(ctx context.Context, key string) error {
 func (d *DatabaseStorage) Close() {
 	d.pool.Close()
 }
+
+func (d *DatabaseStorage) CheckHealth(ctx context.Context) error {
+	conn, err := d.pool.Acquire(ctx)
+	if err != nil {
+		return fmt.Errorf("database connection error: %w", err)
+	}
+	defer conn.Release()
+	return conn.Ping(ctx)
+}

storage/database.go

@@ -41,3 +41,7 @@ func (r *RedisStorage) Set(ctx context.Context, key string, value interface{}, t
 func (r *RedisStorage) Delete(ctx context.Context, key string) {
 	r.client.Del(ctx, key)
 }
+
+func (r *RedisStorage) CheckHealth(ctx context.Context) error {
+	return r.client.Ping(ctx).Err()
+}

storage/redis.go

@@ -51,3 +51,11 @@ func (r *RistrettoCache) Set(ctx context.Context, key string, value string, ttl
 func (r *RistrettoCache) Delete(ctx context.Context, key string) {
 	r.client.Del(key)
 }
+
+func (r *RistrettoCache) CheckHealth(ctx context.Context) error {
+	// Ristretto has no connection state, we only check for initialization
+	if r.client == nil {
+		return errors.New("ristretto cache is not initialized")
+	}
+	return nil
+}