README
¶
go-dlm
This package provides an abstraction library for multiple Distributed Lock Manager backends.
As the moment, go-dlm only supports Redis and an in-memory implementation intended to be used during development.
Usage
// Create a DLM
dlm, err := NewRedisLock("localhost:6379")
if err != nil {
panic(err)
}
// Create a lock
lock, err := dlm.NewLock("resource", nil)
if err != nil {
panic(err)
}
// Acquire the lock
if err := lock.Lock(); err != nil {
panic(err)
}
// Release the lock
if err := lock.Unlock(); err != nil {
panic(err)
}
Copyright and license
Copyright © 2016 MEDIGO GmbH. go-dlm is licensed under the Apache License, Version 2.0. See LICENSE for the full license text.
Documentation
¶
Overview ¶
Package dlm provides an abstraction library for multiple Distributed Lock Manager backends.
Index ¶
Constants ¶
const ( // DefaultTTL is the TTL of the lock after wich it will be automatically released. DefaultTTL = 15 * time.Second // DefaultWaitTime is how long will we wait to acquire a lock. DefaultWaitTime = 15 * time.Second // DefaultRetryTime is how long will we wait after a failed lock adquisition // before attempting to acquire the lock again. DefaultRetryTime = 5 * time.Second )
Variables ¶
var ( // ErrLockHeld is returned if we attempt to acquire a lock that is already held. ErrLockHeld = fmt.Errorf("lock already held") // ErrLockNotHeld is returned if we attempt to release a lock that is not held. ErrLockNotHeld = fmt.Errorf("lock not held") // ErrCannotLock is returned when it's not possible to acquire the lock before // the configured wait time ends. ErrCannotLock = fmt.Errorf("timeout while trying to acquire lock") )
Functions ¶
This section is empty.
Types ¶
type DLM ¶
type DLM interface {
// NewLock creates a lock for the given key. The returned lock is not held
// and must be acquired with a call to .Lock.
NewLock(string, *LockOptions) (Locker, error)
}
DLM describes a Distributed Lock Manager.
type InMemDLM ¶
type InMemDLM struct {
// contains filtered or unexported fields
}
InMemDLM is a local implementation of a DLM that it's intended to be used during development.
type LockOptions ¶
type LockOptions struct {
TTL time.Duration // Optional, defaults to DefaultTTL
WaitTime time.Duration // Optional, defaults to DefaultWaitTime
RetryTime time.Duration // Optional, defaults to DefaultRetryTime
}
LockOptions parameterizes a lock.
func (*LockOptions) WithDefaults ¶
func (lo *LockOptions) WithDefaults() *LockOptions
WithDefaults returns the options with all default values set.
type Locker ¶
type Locker interface {
// Key returns the key to be locked.
Key() string
// Namespace returns the the prefix to be added to the key. If there is not a namespace,
// it returns the empty string.
Namespace() string
// Lock acquires the lock. It fails with error if the lock is already held.
Lock() error
// Unlock releases the lock. It fails with error if the lock is not currently held.
Unlock() error
}
Locker describes a lock that can be locked or unlocked.
type Options ¶
type Options struct {
Namespace string // Optional namespace prefixed to each lock key.
}
Options parameterizes a DLM.
type RedisDLM ¶
type RedisDLM struct {
// contains filtered or unexported fields
}
RedisDLM is a DLM that uses Redis as a backend. The implementation is based in the single node algorithm described here: http://redis.io/topics/distlock
Source Files