chore: import upstream snapshot with attribution

cache/redis/redis.go

@@ -0,0 +1,57 @@
+package redis
+
+import (
+	"context"
+	"time"
+
+	rclient "github.com/go-redis/redis/v8"
+	"go-micro.dev/v6/cache"
+)
+
+// NewRedisCache returns a new redis cache.
+func NewRedisCache(opts ...cache.Option) cache.Cache {
+	options := cache.NewOptions(opts...)
+	return &redisCache{
+		opts:   options,
+		client: newUniversalClient(options),
+	}
+}
+
+type redisCache struct {
+	opts   cache.Options
+	client rclient.UniversalClient
+}
+
+func (c *redisCache) Get(ctx context.Context, key string) (interface{}, time.Time, error) {
+	val, err := c.client.Get(ctx, key).Bytes()
+	if err != nil && err == rclient.Nil {
+		return nil, time.Time{}, cache.ErrKeyNotFound
+	} else if err != nil {
+		return nil, time.Time{}, err
+	}
+
+	dur, err := c.client.TTL(ctx, key).Result()
+	if err != nil {
+		return nil, time.Time{}, err
+	}
+	if dur == -1 {
+		return val, time.Unix(1<<63-1, 0), nil
+	}
+	if dur == -2 {
+		return val, time.Time{}, cache.ErrItemExpired
+	}
+
+	return val, time.Now().Add(dur), nil
+}
+
+func (c *redisCache) Put(ctx context.Context, key string, val interface{}, dur time.Duration) error {
+	return c.client.Set(ctx, key, val, dur).Err()
+}
+
+func (c *redisCache) Delete(ctx context.Context, key string) error {
+	return c.client.Del(ctx, key).Err()
+}
+
+func (c *redisCache) String() string {
+	return "redis"
+}