async

package module
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Published: Jul 29, 2023 License: MIT Imports: 7 Imported by: 20

README


Async is a synchronization and asynchronous computation package for Go.

Overview

  • 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.
  • WaitGroupContext - A WaitGroup with the context.Context support for graceful unblocking.
  • Reentrant Lock - Mutex that allows goroutines to enter into the lock on a resource more than once.
  • Optimistic Lock - Mutex that allows optimistic reading. Could be retried or switched to RLock in case of failure. Significantly improves performance in case of frequent reads and short writes. See benchmarks.

Examples

Can be found in the examples directory/tests.

License

Licensed under the MIT License.

Documentation

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func GoroutineID

func GoroutineID() (uint, error)

GoroutineID returns the current goroutine id.

Types

type Future

type Future[T any] interface {

	// Map creates a new Future by applying a function to the successful result of this Future.
	Map(func(T) (T, error)) Future[T]

	// FlatMap creates a new Future by applying a function to the successful result of
	// this Future.
	FlatMap(func(T) (Future[T], error)) Future[T]

	// Join blocks until the Future is completed and returns either a result or an error.
	Join() (T, error)

	// Get blocks for at most the given time duration for this Future to complete
	// and returns either a result or an error.
	Get(time.Duration) (T, error)

	// Recover handles any error that this Future might contain using a resolver function.
	Recover(func() (T, error)) Future[T]

	// RecoverWith handles any error that this Future might contain using another Future.
	RecoverWith(Future[T]) Future[T]
	// contains filtered or unexported methods
}

Future represents a value which may or may not currently be available, but will be available at some point, or an error if that value could not be made available.

func FutureFirstCompletedOf

func FutureFirstCompletedOf[T any](futures ...Future[T]) Future[T]

FutureFirstCompletedOf asynchronously returns a new Future to the result of the first Future in the list that is completed. This means no matter if it is completed as a success or as a failure.

func FutureSeq

func FutureSeq[T any](futures []Future[T]) Future[[]interface{}]

FutureSeq reduces many Futures into a single Future.

func FutureTimer

func FutureTimer[T any](d time.Duration) Future[T]

FutureTimer returns Future that will have been resolved after given duration; useful for FutureFirstCompletedOf for timeout purposes.

func NewFuture

func NewFuture[T any]() Future[T]

NewFuture returns a new Future.

type FutureImpl

type FutureImpl[T any] struct {
	// contains filtered or unexported fields
}

FutureImpl implements the Future interface.

func (*FutureImpl[T]) FlatMap

func (fut *FutureImpl[T]) FlatMap(f func(T) (Future[T], error)) Future[T]

FlatMap creates a new Future by applying a function to the successful result of this Future and returns the result of the function as a new Future.

func (*FutureImpl[T]) Get

func (fut *FutureImpl[T]) Get(timeout time.Duration) (T, error)

Get blocks for at most the given time duration for this Future to complete and returns either a result or an error.

func (*FutureImpl[T]) Join added in v0.5.0

func (fut *FutureImpl[T]) Join() (T, error)

Join blocks until the Future is completed and returns either a result or an error.

func (*FutureImpl[T]) Map

func (fut *FutureImpl[T]) Map(f func(T) (T, error)) Future[T]

Map creates a new Future by applying a function to the successful result of this Future and returns the result of the function as a new Future.

func (*FutureImpl[T]) Recover

func (fut *FutureImpl[T]) Recover(f func() (T, error)) Future[T]

Recover handles any error that this Future might contain using a given resolver function. Returns the result as a new Future.

func (*FutureImpl[T]) RecoverWith

func (fut *FutureImpl[T]) RecoverWith(rf Future[T]) Future[T]

RecoverWith handles any error that this Future might contain using another Future. Returns the result as a new Future.

type OptimisticLock

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

OptimisticLock allows optimistic reading. Implements the Locker interface and is not reentrant.

func NewOptimisticLock

func NewOptimisticLock() *OptimisticLock

NewOptimisticLock returns a new OptimisticLock.

func (*OptimisticLock) Lock

func (o *OptimisticLock) Lock()

Lock locks the resource for write.

func (*OptimisticLock) OptLock

func (o *OptimisticLock) OptLock() int64

OptLock returns the stamp to be verified on OptUnlock.

func (*OptimisticLock) OptUnlock

func (o *OptimisticLock) OptUnlock(stamp int64) bool

OptUnlock returns true if the lock has not been acquired in write mode since obtaining a given stamp. Retry or switch to RLock in case of failure.

func (*OptimisticLock) RLock

func (o *OptimisticLock) RLock()

RLock locks the resource for read.

func (*OptimisticLock) RUnlock

func (o *OptimisticLock) RUnlock()

RUnlock unlocks the resource after read.

func (*OptimisticLock) Unlock

func (o *OptimisticLock) Unlock()

Unlock unlocks the resource after write.

type Promise

type Promise[T any] interface {

	// Success completes the underlying Future with a value.
	Success(T)

	// Failure fails the underlying Future with an error.
	Failure(error)

	// Future returns the underlying Future.
	Future() Future[T]
}

Promise represents a writable, single-assignment container, which completes a Future.

func NewPromise

func NewPromise[T any]() Promise[T]

NewPromise returns a new PromiseImpl.

type PromiseImpl

type PromiseImpl[T any] struct {
	sync.Mutex
	// contains filtered or unexported fields
}

PromiseImpl implements the Promise interface.

func (*PromiseImpl[T]) Failure

func (p *PromiseImpl[T]) Failure(err error)

Failure fails the underlying Future with a given error.

func (*PromiseImpl[T]) Future

func (p *PromiseImpl[T]) Future() Future[T]

Future returns the underlying Future.

func (*PromiseImpl[T]) Success

func (p *PromiseImpl[T]) Success(value T)

Success completes the underlying Future with a given value.

type ReentrantLock

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

ReentrantLock allows goroutines to enter the lock more than once.

func NewReentrantLock

func NewReentrantLock() *ReentrantLock

NewReentrantLock returns a new ReentrantLock.

func (*ReentrantLock) Lock

func (r *ReentrantLock) Lock()

Lock locks the resource. Panics if the GoroutineID call returns an error.

func (*ReentrantLock) Unlock

func (r *ReentrantLock) Unlock()

Unlock unlocks the resource. Panics on trying to unlock the unlocked lock.

type Task added in v0.4.0

type Task[T any] struct {
	// contains filtered or unexported fields
}

Task is a data type for controlling possibly lazy & asynchronous computations.

func NewTask added in v0.4.0

func NewTask[T any](taskFunc func() (T, error)) *Task[T]

NewTask returns a new Task.

func (*Task[T]) Call added in v0.4.0

func (task *Task[T]) Call() Future[T]

Call executes the Task and returns a Future.

type WaitGroupContext added in v0.5.0

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

A WaitGroupContext waits for a collection of goroutines to finish. The main goroutine calls Add to set the number of goroutines to wait for. Then each of the goroutines runs and calls Done when finished. At the same time, Wait can be used to block until all goroutines have finished or the given context is done.

func NewWaitGroupContext added in v0.5.0

func NewWaitGroupContext(ctx context.Context) *WaitGroupContext

NewWaitGroupContext returns a new WaitGroupContext with Context ctx.

func (*WaitGroupContext) Add added in v0.5.0

func (wgc *WaitGroupContext) Add(delta int)

Add adds delta, which may be negative, to the WaitGroupContext counter. If the counter becomes zero, all goroutines blocked on Wait are released. If the counter goes negative, Add panics.

func (*WaitGroupContext) Done added in v0.5.0

func (wgc *WaitGroupContext) Done()

Done decrements the WaitGroupContext counter by one.

func (*WaitGroupContext) Wait added in v0.5.0

func (wgc *WaitGroupContext) Wait()

Wait blocks until the wait group counter is zero or ctx is done.

Directories

Path Synopsis
examples
future command
goroutine command

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