initial commit 2

infra/cache/cache.go

@@ -0,0 +1,144 @@
+package cache
+
+import (
+	"encoding/json"
+	"fmt"
+
+	redis "gopkg.in/redis.v5"
+
+	"time"
+
+	"sync"
+
+	"bitbucket.org/nemt/nemt-portal-api/domain"
+	"bitbucket.org/nemt/nemt-portal-api/domain/contract"
+	"bitbucket.org/nemt/nemt-portal-api/infra/config"
+	"bitbucket.org/nemt/nemt-portal-api/infra/errors"
+)
+
+var (
+	instance *RedisCache
+	once     sync.Once
+)
+
+// RedisCache implements the CacheManager interface
+type RedisCache struct {
+	cfg   *config.Config
+	redis *redis.Client
+}
+
+// Instance returns a CacheManager instance
+func Instance(cfg *config.Config) contract.CacheManager {
+	once.Do(func() {
+		client := redis.NewFailoverClient(&redis.FailoverOptions{
+			MasterName:    "master01",
+			SentinelAddrs: []string{fmt.Sprintf("%s:%v", cfg.Cache.Server, cfg.Cache.Port)},
+			Password:      cfg.Cache.Pass,
+			DB:            cfg.Cache.DB,
+		})
+
+		instance = &RedisCache{cfg, client}
+	})
+
+	return instance
+}
+
+func (r *RedisCache) buildKey(key string) string {
+	return fmt.Sprintf("%s-%s", r.cfg.Cache.Prefix, key)
+}
+
+// GetItem returns an Item from cache
+func (r *RedisCache) GetItem(key string) (data []byte, err error) {
+	val, err := r.redis.Get(r.buildKey(key)).Bytes()
+	if err == redis.Nil {
+		return val, domain.ErrCacheMiss
+	} else if err != nil {
+		return val, errors.Wrap(err)
+	}
+
+	return val, nil
+}
+
+// SetItem sets an item in cache
+func (r *RedisCache) SetItem(key string, data []byte) error {
+	err := r.redis.Set(r.buildKey(key), data, r.cfg.Cache.DefaultExpiration).Err()
+	if err != nil {
+		return errors.Wrap(err)
+	}
+
+	return nil
+}
+
+// GetString returns an string from cache
+func (r *RedisCache) GetString(key string) (data string, err error) {
+	val, err := r.GetItem(key)
+	if err == domain.ErrCacheMiss {
+		return data, domain.ErrCacheMiss
+	} else if err != nil {
+		return data, errors.Wrap(err)
+	}
+
+	return string(val), nil
+}
+
+// SetString sets an item in cache
+func (r *RedisCache) SetString(key string, data string) error {
+	err := r.SetItem(key, []byte(data))
+	if err != nil {
+		return errors.Wrap(err)
+	}
+
+	return nil
+}
+
+// GetStruct returns an struct from cache
+func (r *RedisCache) GetStruct(key string, data interface{}) (err error) {
+	val, err := r.GetItem(key)
+	if err == domain.ErrCacheMiss {
+		return domain.ErrCacheMiss
+	} else if err != nil {
+		return errors.Wrap(err)
+	}
+
+	err = json.Unmarshal(val, &data)
+	if err != nil {
+		return errors.Wrap(err)
+	}
+
+	return nil
+}
+
+// SetStruct sets an item in cache
+func (r *RedisCache) SetStruct(key string, data interface{}) error {
+	dataString, err := json.Marshal(data)
+	if err != nil {
+		return errors.Wrap(err)
+	}
+
+	err = r.SetItem(key, dataString)
+	if err != nil {
+		return errors.Wrap(err)
+	}
+
+	return nil
+}
+
+// GetExpiration returns the expiration time for a key
+func (r *RedisCache) GetExpiration(key string) (expiration time.Duration, err error) {
+	expiration, err = r.redis.TTL(r.buildKey(key)).Result()
+	if err != nil {
+		return expiration, errors.Wrap(err)
+	}
+
+	return expiration, nil
+}
+
+// SetExpiration sets the expiration time for a key
+func (r *RedisCache) SetExpiration(key string, expiration time.Duration) (err error) {
+	err = r.redis.Expire(r.buildKey(key), expiration).Err()
+	if err != nil {
+		return errors.Wrap(err)
+	}
+
+	return nil
+}