FEAT: Added Redis Caching

discovery/internal/services/cache.go

@@ -0,0 +1,58 @@
+package services
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log"
+	"time"
+
+	"github.com/redis/go-redis/v9"
+)
+
+var CacheClient Cache
+
+var ErrCacheMiss = errors.New("cache: miss")
+
+type Cache interface {
+	Get(ctx context.Context, key string) ([]byte, error)
+	Set(ctx context.Context, key string, value []byte, ttl time.Duration) error
+}
+
+type RedisConcrete struct {
+	Redis *redis.Client
+}
+
+const cacheOperationTimeout = 100 * time.Millisecond
+
+func (svc RedisConcrete) Get(ctx context.Context, key string) ([]byte, error) {
+	ctx, cancel := context.WithTimeout(ctx, cacheOperationTimeout)
+	defer cancel()
+
+	value, err := svc.Redis.Get(ctx, key).Bytes()
+	if errors.Is(err, redis.Nil) {
+		return nil, ErrCacheMiss
+	}
+	if err != nil {
+		return nil, err
+	}
+	return value, nil
+}
+
+func (svc RedisConcrete) Set(ctx context.Context, key string, value []byte, ttl time.Duration) error {
+	ctx, cancel := context.WithTimeout(ctx, cacheOperationTimeout)
+	defer cancel()
+
+	return svc.Redis.Set(ctx, key, value, ttl).Err()
+}
+
+func (svc RedisConcrete) Close() error {
+	return svc.Redis.Close()
+}
+
+func (svc RedisConcrete) AssertSuccessfulConnection(ctx context.Context) {
+	if err := svc.Redis.Ping(ctx).Err(); err != nil {
+		log.Printf("WARNING: %s", fmt.Errorf("redis: cannot reach cache at %q, searches will be served from the database: %w",
+			svc.Redis.Options().Addr, err))
+	}
+}