reugn / async

Synchronization and asynchronous computation package for Go

Async is a synchronization and asynchronous computation package for Go.

Overview

• ConcurrentMap - Implements the generic async.Map interface in a thread-safe manner by delegating load/store operations to the underlying sync.Map.
• ShardedMap - Implements the generic async.Map interface in a thread-safe manner, delegating load/store operations to one of the underlying async.SynchronizedMaps (shards), using a key hash to calculate the shard number.
• Future - A placeholder object for a value that may not yet exist.
• Promise - While futures are defined as a type of read-only placeholder object created for a result which doesn’t yet exist, a promise can be thought of as a writable, single-assignment container, which completes a future.
• Task - A data type for controlling possibly lazy and asynchronous computations.
• Once - An object similar to sync.Once having the Do method taking f func() (T, error) and returning (T, error).
• Value - An object similar to atomic.Value, but without the consistent type constraint.
• WaitGroupContext - A WaitGroup with the context.Context support for graceful unblocking.
• ReentrantLock - A mutex that allows goroutines to enter into the lock on a resource more than once.
• PriorityLock - A non-reentrant mutex that allows for the specification of lock acquisition priority.

Examples

Can be found in the examples directory/tests.

License

Licensed under the MIT License.

async's Issues

Get with timeout cause goroutine leak

If I use the Get method with a 2s timeout, then a goroutine leak will occur from the call to comple after 2s.

package main

import (
	"fmt"
	"runtime"
	"sync"
	"time"

	"github.com/reugn/async"
)

func main() {
	var wg sync.WaitGroup

	fmt.Println(runtime.NumGoroutine()) // 101

	for i := 0; i < 100; i++ {
		promise := async.NewPromise[string]()
		go func() {
			wg.Add(1)
			defer wg.Done()
			time.Sleep(time.Second * 4)
			promise.Success("OK")
		}()
		go func() {
			wg.Add(1)
			defer wg.Done()
			fut := promise.Future()
			_, _ = fut.Get(time.Second * 2)
			time.Sleep(time.Second * 4)
			_, _ = fut.Join()
		}()
	}

	wg.Wait()
	fmt.Println(runtime.NumGoroutine()) // 101
}