sema

README

Sema

Sema is a simple semaphore implementation for Go (golang) to control concurrent access to shared resources. (Go still lacks a user accessible semaphore implementation in the standard library)

Example

Install

go get github.com/brunotm/sema

Usage

package main
import (
	"time"
	"github.com/brunotm/sema"
)

func main() {
	max := 100
	s := sema.New(max)

	s.Acquire()
	defer s.Release()
	// DO WORK...

	// OR
	if s.TryAcquire() {
		defer s.Release()
		// DO WORK...
	}

	// OR
	if s.AcquireWithin(5 * time.Millisecond) {
		defer s.Release()
		// DO WORK...
	}

}

Written by Bruno Moura brunotm@gmail.com

Documentation

Index

• type Sema
  • func New(cap int) (s *Sema, err error)
  • func (s *Sema) Acquire()
  • func (s *Sema) AcquireWithin(timeout time.Duration) bool
  • func (s *Sema) Cap() int
  • func (s *Sema) Holders() int
  • func (s *Sema) Release()
  • func (s *Sema) TryAcquire() bool

Types

type Sema

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

Sema provides a simple semaphore implementation

func New

func New(cap int) (s *Sema, err error)

New creates a new semaphore with the given maximum capacity for concurrent access.

func (*Sema) Acquire

func (s *Sema) Acquire()

Acquire the semaphore, will block if semaphore is full until any other holder release it.

func (*Sema) AcquireWithin

func (s *Sema) AcquireWithin(timeout time.Duration) bool

AcquireWithin the given timeout return true on success and false on failure

func (*Sema) Cap

func (s *Sema) Cap() int

Cap return semaphore capacity

func (*Sema) Holders

func (s *Sema) Holders() int

Holders return the current holders count

func (*Sema) Release

func (s *Sema) Release()

Release the semaphore allowing waking waiters if any to acquire.

func (*Sema) TryAcquire

func (s *Sema) TryAcquire() bool

TryAcquire the semaphore without blocking return true on success and false on failure.