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Copy pathenforcer_cached.go
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220 lines (193 loc) · 5.69 KB
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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
package casbin
import (
"strconv"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/casbin/casbin/v3/persist/cache"
)
// CachedEnforcer wraps Enforcer and provides decision cache.
type CachedEnforcer struct {
*Enforcer
cacheVersion uint64
expireTime time.Duration
cache cache.Cache
enableCache int32
locker *sync.RWMutex
}
type CacheableParam interface {
GetCacheKey() string
}
// NewCachedEnforcer creates a cached enforcer via file or DB.
func NewCachedEnforcer(params ...interface{}) (*CachedEnforcer, error) {
e := &CachedEnforcer{}
var err error
e.Enforcer, err = NewEnforcer(params...)
if err != nil {
return nil, err
}
e.enableCache = 1
e.cache, _ = cache.NewDefaultCache()
e.locker = new(sync.RWMutex)
e.cacheVersion = e.getPolicyVersion()
return e, nil
}
// EnableCache determines whether to enable cache on Enforce(). When enableCache is enabled, cached result (true | false) will be returned for previous decisions.
func (e *CachedEnforcer) EnableCache(enableCache bool) {
var enabled int32
if enableCache {
enabled = 1
}
atomic.StoreInt32(&e.enableCache, enabled)
}
// Enforce decides whether a "subject" can access a "object" with the operation "action", input parameters are usually: (sub, obj, act).
// if rvals is not string , ignore the cache.
func (e *CachedEnforcer) Enforce(rvals ...interface{}) (bool, error) {
if atomic.LoadInt32(&e.enableCache) == 0 {
return e.Enforcer.Enforce(rvals...)
}
key, ok := e.getKey(rvals...)
if !ok {
return e.Enforcer.Enforce(rvals...)
}
version := e.getPolicyVersion()
if err := e.syncCacheVersion(version); err != nil {
return false, err
}
if res, err := e.getCachedResult(key); err == nil {
return res, nil
} else if err != cache.ErrNoSuchKey {
return res, err
}
res, err := e.Enforcer.Enforce(rvals...)
if err != nil {
return false, err
}
err = e.setCachedResult(version, key, res, e.expireTime)
return res, err
}
func (e *CachedEnforcer) LoadPolicy() error {
if atomic.LoadInt32(&e.enableCache) != 0 {
if err := e.cache.Clear(); err != nil {
return err
}
}
return e.Enforcer.LoadPolicy()
}
func (e *CachedEnforcer) RemovePolicy(params ...interface{}) (bool, error) {
if atomic.LoadInt32(&e.enableCache) != 0 {
key, ok := e.getKey(params...)
if ok {
if err := e.cache.Delete(key); err != nil && err != cache.ErrNoSuchKey {
return false, err
}
}
}
return e.Enforcer.RemovePolicy(params...)
}
func (e *CachedEnforcer) RemovePolicies(rules [][]string) (bool, error) {
if len(rules) != 0 {
if atomic.LoadInt32(&e.enableCache) != 0 {
for _, rule := range rules {
irule := make([]interface{}, len(rule))
for i, param := range rule {
irule[i] = param
}
key, _ := e.getKey(irule...)
if err := e.cache.Delete(key); err != nil && err != cache.ErrNoSuchKey {
return false, err
}
}
}
}
return e.Enforcer.RemovePolicies(rules)
}
func (e *CachedEnforcer) getCachedResult(key string) (res bool, err error) {
e.locker.Lock()
defer e.locker.Unlock()
return e.cache.Get(key)
}
func (e *CachedEnforcer) SetExpireTime(expireTime time.Duration) {
e.expireTime = expireTime
}
func (e *CachedEnforcer) SetCache(c cache.Cache) {
e.cache = c
}
func (e *CachedEnforcer) getKey(params ...interface{}) (string, bool) {
return GetCacheKey(params...)
}
// InvalidateCache deletes all the existing cached decisions.
func (e *CachedEnforcer) InvalidateCache() error {
e.locker.Lock()
defer e.locker.Unlock()
return e.cache.Clear()
}
func GetCacheKey(params ...interface{}) (string, bool) {
key := strings.Builder{}
for _, param := range params {
switch typedParam := param.(type) {
case string:
writeCacheKeyPart(&key, 's', typedParam)
case CacheableParam:
writeCacheKeyPart(&key, 'c', typedParam.GetCacheKey())
default:
return "", false
}
}
return key.String(), true
}
// writeCacheKeyPart length-prefixes each part so that different requests never share a key.
func writeCacheKeyPart(key *strings.Builder, kind byte, part string) {
key.WriteByte(kind)
key.WriteString(strconv.Itoa(len(part)))
key.WriteByte(':')
key.WriteString(part)
}
// ClearPolicy clears all policy.
func (e *CachedEnforcer) ClearPolicy() {
if atomic.LoadInt32(&e.enableCache) != 0 {
if err := e.cache.Clear(); err != nil {
// Logger has been removed - error is ignored
return
}
}
e.Enforcer.ClearPolicy()
}
// syncCacheVersion drops all cached decisions when the policy has changed since they were cached.
func (e *CachedEnforcer) syncCacheVersion(version uint64) error {
e.locker.Lock()
defer e.locker.Unlock()
if version <= e.cacheVersion {
return nil
}
if err := e.cache.Clear(); err != nil {
return err
}
e.cacheVersion = version
return nil
}
func (e *CachedEnforcer) setCachedResult(version uint64, key string, res bool, extra ...interface{}) error {
e.locker.Lock()
defer e.locker.Unlock()
if version != e.cacheVersion {
return nil
}
return e.cache.Set(key, res, extra...)
}