removes memory as distcache option

if database caching is to expensive if should
not use distcache in the first place.

pkg/infra/distcache/distcache.go

@@ -40,10 +40,6 @@ func createClient(opts *setting.CacheOpts, sqlstore *sqlstore.SqlStore) cacheSto
 		return newMemcacheStorage(opts)
 	}
 
-	if opts.Name == "memory" {
-		return newMemoryStorage()
-	}
-
 	return newDatabaseCache(sqlstore)
 }
 

pkg/infra/distcache/memory_storage.go

-package distcache
-
-import (
-	"time"
-
-	gocache "github.com/patrickmn/go-cache"
-)
-
-type memoryStorage struct {
-	c *gocache.Cache
-}
-
-func newMemoryStorage() *memoryStorage {
-	return &memoryStorage{
-		c: gocache.New(time.Minute*30, time.Minute*30),
-	}
-}
-
-func (s *memoryStorage) Put(key string, val interface{}, expires time.Duration) error {
-	return s.c.Add(key, val, expires)
-}
-
-func (s *memoryStorage) Get(key string) (interface{}, error) {
-	val, exist := s.c.Get(key)
-	if !exist {
-		return nil, ErrCacheItemNotFound
-	}
-
-	return val, nil
-}
-
-func (s *memoryStorage) Delete(key string) error {
-	s.c.Delete(key)
-	return nil
-}

pkg/infra/distcache/memory_storage_test.go

-package distcache
-
-import (
-	"testing"
-
-	"github.com/grafana/grafana/pkg/setting"
-)
-
-func TestMemoryCacheStorage(t *testing.T) {
-	opts := &setting.CacheOpts{Name: "memory"}
-	runTestsForClient(t, createTestClient(t, opts, nil))
-}