83 lines
2.3 KiB
Go
83 lines
2.3 KiB
Go
/*
|
|
Copyright 2015 The Kubernetes Authors.
|
|
|
|
Licensed 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 keymutex
|
|
|
|
import (
|
|
"fmt"
|
|
"sync"
|
|
|
|
"github.com/golang/glog"
|
|
)
|
|
|
|
// KeyMutex is a thread-safe interface for acquiring locks on arbitrary strings.
|
|
type KeyMutex interface {
|
|
// Acquires a lock associated with the specified ID, creates the lock if one doesn't already exist.
|
|
LockKey(id string)
|
|
|
|
// Releases the lock associated with the specified ID.
|
|
// Returns an error if the specified ID doesn't exist.
|
|
UnlockKey(id string) error
|
|
}
|
|
|
|
// Returns a new instance of a key mutex.
|
|
func NewKeyMutex() KeyMutex {
|
|
return &keyMutex{
|
|
mutexMap: make(map[string]*sync.Mutex),
|
|
}
|
|
}
|
|
|
|
type keyMutex struct {
|
|
sync.RWMutex
|
|
mutexMap map[string]*sync.Mutex
|
|
}
|
|
|
|
// Acquires a lock associated with the specified ID (creates the lock if one doesn't already exist).
|
|
func (km *keyMutex) LockKey(id string) {
|
|
glog.V(5).Infof("LockKey(...) called for id %q\r\n", id)
|
|
mutex := km.getOrCreateLock(id)
|
|
mutex.Lock()
|
|
glog.V(5).Infof("LockKey(...) for id %q completed.\r\n", id)
|
|
}
|
|
|
|
// Releases the lock associated with the specified ID.
|
|
// Returns an error if the specified ID doesn't exist.
|
|
func (km *keyMutex) UnlockKey(id string) error {
|
|
glog.V(5).Infof("UnlockKey(...) called for id %q\r\n", id)
|
|
km.RLock()
|
|
defer km.RUnlock()
|
|
mutex, exists := km.mutexMap[id]
|
|
if !exists {
|
|
return fmt.Errorf("id %q not found", id)
|
|
}
|
|
glog.V(5).Infof("UnlockKey(...) for id. Mutex found, trying to unlock it. %q\r\n", id)
|
|
|
|
mutex.Unlock()
|
|
glog.V(5).Infof("UnlockKey(...) for id %q completed.\r\n", id)
|
|
return nil
|
|
}
|
|
|
|
// Returns lock associated with the specified ID, or creates the lock if one doesn't already exist.
|
|
func (km *keyMutex) getOrCreateLock(id string) *sync.Mutex {
|
|
km.Lock()
|
|
defer km.Unlock()
|
|
|
|
if _, exists := km.mutexMap[id]; !exists {
|
|
km.mutexMap[id] = &sync.Mutex{}
|
|
}
|
|
|
|
return km.mutexMap[id]
|
|
}
|