/
redis.go
246 lines (218 loc) · 5.72 KB
/
redis.go
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/**
* Author: Tony.Shao
* Email: xiocode@gmail.com
* Github: github.com/xiocode
* File: redis.go
* Description: fork revel's cache
**/
package cache
import (
"time"
"github.com/garyburd/redigo/redis"
)
// Wraps the Redis client to meet the Cache interface.
type RedisCache struct {
pool *redis.Pool
defaultExpiration time.Duration
}
// until redigo supports sharding/clustering, only one host will be in hostList
func NewRedisCache(host string, password string, defaultExpiration time.Duration) RedisCache {
var pool = &redis.Pool{
MaxIdle: 5,
IdleTimeout: 120 * time.Second,
Dial: func() (redis.Conn, error) {
protocol := "tcp"
c, err := redis.DialTimeout(protocol, host, 1*time.Second, 1*time.Second, 1*time.Second)
if err != nil {
return nil, err
}
// check with PING
if _, err := c.Do("PING"); err != nil {
c.Close()
return nil, err
}
return c, err
},
// custom connection test method
TestOnBorrow: func(c redis.Conn, t time.Time) error {
if _, err := c.Do("PING"); err != nil {
return err
}
return nil
},
}
return RedisCache{pool, defaultExpiration}
}
func (c RedisCache) Set(key string, value interface{}, expires time.Duration) error {
conn := c.pool.Get()
defer conn.Close()
return c.invoke(conn.Do, key, value, expires)
}
func (c RedisCache) Add(key string, value interface{}, expires time.Duration) error {
conn := c.pool.Get()
defer conn.Close()
existed, err := exists(conn, key)
if err != nil {
return err
} else if existed {
return ErrNotStored
}
return c.invoke(conn.Do, key, value, expires)
}
func (c RedisCache) Replace(key string, value interface{}, expires time.Duration) error {
conn := c.pool.Get()
defer conn.Close()
existed, err := exists(conn, key)
if err != nil {
return err
} else if !existed {
return ErrNotStored
}
err = c.invoke(conn.Do, key, value, expires)
if value == nil {
return ErrNotStored
} else {
return err
}
}
func (c RedisCache) Get(key string, ptrValue interface{}) error {
conn := c.pool.Get()
defer conn.Close()
raw, err := conn.Do("GET", key)
if err != nil {
return err
} else if raw == nil {
return ErrCacheMiss
}
item, err := redis.Bytes(raw, err)
if err != nil {
return err
}
return Deserialize(item, ptrValue)
}
func generalizeStringSlice(strs []string) []interface{} {
ret := make([]interface{}, len(strs))
for i, str := range strs {
ret[i] = str
}
return ret
}
func (c RedisCache) GetMulti(keys ...string) (Getter, error) {
conn := c.pool.Get()
defer conn.Close()
items, err := redis.Values(conn.Do("MGET", generalizeStringSlice(keys)...))
if err != nil {
return nil, err
} else if items == nil {
return nil, ErrCacheMiss
}
m := make(map[string][]byte)
for i, key := range keys {
m[key] = nil
if i < len(items) && items[i] != nil {
s, ok := items[i].([]byte)
if ok {
m[key] = s
}
}
}
return RedisItemMapGetter(m), nil
}
func exists(conn redis.Conn, key string) (bool, error) {
return redis.Bool(conn.Do("EXISTS", key))
}
func (c RedisCache) Exists(key string) (bool, error) {
conn := c.pool.Get()
defer conn.Close()
return exists(conn, key)
}
func (c RedisCache) Delete(key string) error {
conn := c.pool.Get()
defer conn.Close()
existed, err := redis.Bool(conn.Do("DEL", key))
if err == nil && !existed {
err = ErrCacheMiss
}
return err
}
func (c RedisCache) Increment(key string, delta uint64) (uint64, error) {
conn := c.pool.Get()
defer conn.Close()
// Check for existance *before* increment as per the cache contract.
// redis will auto create the key, and we don't want that. Since we need to do increment
// ourselves instead of natively via INCRBY (redis doesn't support wrapping), we get the value
// and do the exists check this way to minimize calls to Redis
existed, err := exists(conn, key)
if err != nil {
return 0, err
} else if !existed {
return 0, ErrCacheMiss
}
val, err := redis.Int64(conn.Do("INCRBY", key, delta))
if err != nil {
return 0, err
}
return uint64(val), nil
}
func (c RedisCache) Decrement(key string, delta uint64) (newValue uint64, err error) {
conn := c.pool.Get()
defer conn.Close()
// Check for existance *before* increment as per the cache contract.
// redis will auto create the key, and we don't want that, hence the exists call
existed, err := exists(conn, key)
if err != nil {
return 0, err
} else if !existed {
return 0, ErrCacheMiss
}
// Decrement contract says you can only go to 0
// so we go fetch the value and if the delta is greater than the amount,
// 0 out the value
currentVal, err := redis.Int64(conn.Do("GET", key))
if err != nil {
return 0, err
}
if delta > uint64(currentVal) {
tempint, err := redis.Int64(conn.Do("DECRBY", key, currentVal))
return uint64(tempint), err
}
tempint, err := redis.Int64(conn.Do("DECRBY", key, delta))
return uint64(tempint), err
}
func (c RedisCache) Flush() error {
conn := c.pool.Get()
defer conn.Close()
_, err := conn.Do("FLUSHALL")
return err
}
func (c RedisCache) invoke(f func(string, ...interface{}) (interface{}, error),
key string, value interface{}, expires time.Duration) error {
switch expires {
case DEFAULT:
expires = c.defaultExpiration
case FOREVER:
expires = time.Duration(0)
}
b, err := Serialize(value)
if err != nil {
return err
}
conn := c.pool.Get()
defer conn.Close()
if expires > 0 {
_, err := f("SETEX", key, int32(expires/time.Second), b)
return err
} else {
_, err := f("SET", key, b)
return err
}
}
// Implement a Getter on top of the returned item map.
type RedisItemMapGetter map[string][]byte
func (g RedisItemMapGetter) Get(key string, ptrValue interface{}) error {
item, ok := g[key]
if !ok {
return ErrCacheMiss
}
return Deserialize(item, ptrValue)
}