Packages

final class TaskSemaphore extends Serializable

The TaskSemaphore is an asynchronous semaphore implementation that limits the parallelism on task execution.

The following example instantiates a semaphore with a maximum parallelism of 10:

val semaphore = TaskSemaphore(maxParallelism = 10)

def makeRequest(r: HttpRequest): Task[HttpResponse] = ???

// For such a task no more than 10 requests
// are allowed to be executed in parallel.
val task = semaphore.greenLight(makeRequest(???))
Source
TaskSemaphore.scala
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Serializable, Serializable, AnyRef, Any
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Value Members

  1. val acquire: Task[Unit]

    Triggers a permit acquisition, returning a task that upon evaluation will only complete after a permit has been acquired.

  2. def activeCount: Coeval[Int]

    Returns the number of active tasks that are holding on to the available permits.

  3. val awaitAllReleased: Task[Unit]

    Returns a task, that upon evaluation will be complete when all the currently acquired permits are released, or in other words when the activeCount is zero.

    Returns a task, that upon evaluation will be complete when all the currently acquired permits are released, or in other words when the activeCount is zero.

    This also means that we are going to wait for the acquisition and release of all enqueued promises as well.

  4. def greenLight[A](fa: Task[A]): Task[A]

    Creates a new task ensuring that the given source acquires an available permit from the semaphore before it is being executed.

    Creates a new task ensuring that the given source acquires an available permit from the semaphore before it is being executed.

    The returned task also takes care of resource handling, releasing its permit after being complete.

  5. val release: Task[Unit]

    Returns a task that upon evaluation will release a permit, returning it to the pool.

    Returns a task that upon evaluation will release a permit, returning it to the pool.

    If there are consumers waiting on permits being available, then the first in the queue will be selected and given a permit immediately.