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memcache.go
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memcache.go
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package store
import (
"errors"
"fmt"
"strings"
time "time"
"github.com/bradfitz/gomemcache/memcache"
)
// MemcacheClientInterface represents a bradfitz/gomemcache client
type MemcacheClientInterface interface {
Get(key string) (item *memcache.Item, err error)
Set(item *memcache.Item) error
Delete(item string) error
FlushAll() error
}
const (
// MemcacheType represents the storage type as a string value
MemcacheType = "memcache"
// MemcacheTagPattern represents the tag pattern to be used as a key in specified storage
MemcacheTagPattern = "gocache_tag_%s"
)
// MemcacheStore is a store for Memcache
type MemcacheStore struct {
client MemcacheClientInterface
options *Options
}
// NewMemcache creates a new store to Memcache instance(s)
func NewMemcache(client MemcacheClientInterface, options *Options) *MemcacheStore {
if options == nil {
options = &Options{}
}
return &MemcacheStore{
client: client,
options: options,
}
}
// Get returns data stored from a given key
func (s *MemcacheStore) Get(key interface{}) (interface{}, error) {
item, err := s.client.Get(key.(string))
if err != nil {
return nil, err
}
if item == nil {
return nil, errors.New("Unable to retrieve data from memcache")
}
return item.Value, err
}
// GetWithTTL returns data stored from a given key and its corresponding TTL
func (s *MemcacheStore) GetWithTTL(key interface{}) (interface{}, time.Duration, error) {
item, err := s.client.Get(key.(string))
if err != nil {
return nil, 0, err
}
if item == nil {
return nil, 0, errors.New("Unable to retrieve data from memcache")
}
return item.Value, time.Duration(item.Expiration) * time.Second, err
}
// Set defines data in Memcache for given key identifier
func (s *MemcacheStore) Set(key interface{}, value interface{}, options *Options) error {
if options == nil {
options = s.options
}
item := &memcache.Item{
Key: key.(string),
Value: value.([]byte),
Expiration: int32(options.ExpirationValue().Seconds()),
}
err := s.client.Set(item)
if err != nil {
return err
}
if tags := options.TagsValue(); len(tags) > 0 {
s.setTags(key, tags)
}
return nil
}
func (s *MemcacheStore) setTags(key interface{}, tags []string) {
for _, tag := range tags {
var tagKey = fmt.Sprintf(MemcacheTagPattern, tag)
var cacheKeys = []string{}
if result, err := s.Get(tagKey); err == nil {
if bytes, ok := result.([]byte); ok {
cacheKeys = strings.Split(string(bytes), ",")
}
}
var alreadyInserted = false
for _, cacheKey := range cacheKeys {
if cacheKey == key.(string) {
alreadyInserted = true
break
}
}
if !alreadyInserted {
cacheKeys = append(cacheKeys, key.(string))
}
s.Set(tagKey, []byte(strings.Join(cacheKeys, ",")), &Options{
Expiration: 720 * time.Hour,
})
}
}
// Delete removes data from Memcache for given key identifier
func (s *MemcacheStore) Delete(key interface{}) error {
return s.client.Delete(key.(string))
}
// Invalidate invalidates some cache data in Redis for given options
func (s *MemcacheStore) Invalidate(options InvalidateOptions) error {
if tags := options.TagsValue(); len(tags) > 0 {
for _, tag := range tags {
var tagKey = fmt.Sprintf(MemcacheTagPattern, tag)
result, err := s.Get(tagKey)
if err != nil {
return nil
}
var cacheKeys = []string{}
if bytes, ok := result.([]byte); ok {
cacheKeys = strings.Split(string(bytes), ",")
}
for _, cacheKey := range cacheKeys {
s.Delete(cacheKey)
}
}
}
return nil
}
// Clear resets all data in the store
func (s *MemcacheStore) Clear() error {
return s.client.FlushAll()
}
// GetType returns the store type
func (s *MemcacheStore) GetType() string {
return MemcacheType
}