lock

Documentation

Index

• Constants
• Variables
• type EtcdLockClient
  • func NewEtcdLockClient(keyapi KeysAPI, group string) (*EtcdLockClient, error)
  • func (c *EtcdLockClient) Get() (*Semaphore, error)
  • func (c *EtcdLockClient) Init() error
  • func (c *EtcdLockClient) Set(sem *Semaphore) error
• type KeysAPI
• type Lock
  • func New(id string, client LockClient) (lock *Lock)
  • func (l *Lock) Get() (sem *Semaphore, err error)
  • func (l *Lock) Lock() (err error)
  • func (l *Lock) SetMax(max int) (sem *Semaphore, oldMax int, err error)
  • func (l *Lock) Unlock() error
• type LockClient
• type Semaphore
  • func (s *Semaphore) Lock(h string) error
  • func (s *Semaphore) SetMax(max int) error
  • func (s *Semaphore) String() string
  • func (s *Semaphore) Unlock(h string) error

Constants

const (
	SemaphorePrefix = keyPrefix + "/" + semaphoreBranch
)

Variables

var (
	ErrExist    = errors.New("holder exists")
	ErrNotExist = errors.New("holder does not exist")
)

Types

type EtcdLockClient

type EtcdLockClient struct {
	// contains filtered or unexported fields
}

EtcdLockClient is a wrapper around the etcd client that provides simple primitives to operate on the internal semaphore and holders structs through etcd.

func NewEtcdLockClient

func NewEtcdLockClient(keyapi KeysAPI, group string) (*EtcdLockClient, error)

NewEtcdLockClient creates a new EtcdLockClient. The group parameter defines the etcd key path in which the client will manipulate the semaphore. If the group is the empty string, the default semaphore will be used.

func (*EtcdLockClient) Get

func (c *EtcdLockClient) Get() (*Semaphore, error)

Get fetches the Semaphore from etcd.

func (*EtcdLockClient) Init

func (c *EtcdLockClient) Init() error

Init sets an initial copy of the semaphore if it doesn't exist yet.

func (*EtcdLockClient) Set

func (c *EtcdLockClient) Set(sem *Semaphore) error

Set sets a Semaphore in etcd.

type KeysAPI

type KeysAPI interface {
	Get(ctx context.Context, key string, opts *client.GetOptions) (*client.Response, error)
	Set(ctx context.Context, key, value string, opts *client.SetOptions) (*client.Response, error)
	Create(ctx context.Context, key, value string) (*client.Response, error)
}

KeysAPI is the minimum etcd client.KeysAPI interface EtcdLockClient needs to do its job.

type Lock

type Lock struct {
	// contains filtered or unexported fields
}

func New

func New(id string, client LockClient) (lock *Lock)

func (*Lock) Get

func (l *Lock) Get() (sem *Semaphore, err error)

func (*Lock) Lock

func (l *Lock) Lock() (err error)

func (*Lock) SetMax

func (l *Lock) SetMax(max int) (sem *Semaphore, oldMax int, err error)

func (*Lock) Unlock

func (l *Lock) Unlock() error

type LockClient

type LockClient interface {
	Init() error
	Get() (*Semaphore, error)
	Set(*Semaphore) error
}

type Semaphore

type Semaphore struct {
	Index     uint64   `json:"-"`
	Semaphore int      `json:"semaphore"`
	Max       int      `json:"max"`
	Holders   []string `json:"holders"`
}

func (*Semaphore) Lock

func (s *Semaphore) Lock(h string) error

func (*Semaphore) SetMax

func (s *Semaphore) SetMax(max int) error

func (*Semaphore) String

func (s *Semaphore) String() string

func (*Semaphore) Unlock

func (s *Semaphore) Unlock(h string) error