TaskGroup::any

Create a Future that resolves with the result of the first successful task.

TaskGroup::any ​

(PHP 8.6+, True Async 1.0)

php
public TaskGroup::any(): Async\Future

Returns a Future that resolves with the result of the first successfully completed task. Tasks that failed with an error are skipped. The remaining tasks continue running.

If all tasks fail with errors, the Future rejects with CompositeException.

The returned Future supports a cancellation token via await(?Completable $cancellation).

Return Value ​

Async\Future --- a future result of the first successful task. Call ->await() to get the value.

Errors ​

  • Throws Async\AsyncException if the group is empty.
  • The Future rejects with Async\CompositeException if all tasks fail with errors.

Examples ​

Example #1 First successful ​

php
<?php

use Async\TaskGroup;

spawn(function() {
    $group = new TaskGroup();

    $group->spawn(fn() => throw new \RuntimeException("fail 1"));
    $group->spawn(fn() => throw new \RuntimeException("fail 2"));
    $group->spawn(fn() => "success!");

    $result = $group->any()->await();
    echo $result . "\n"; // "success!"

    // Errors from failed tasks must be explicitly suppressed
    $group->suppressErrors();
});

Example #2 All failed ​

php
<?php

use Async\TaskGroup;

spawn(function() {
    $group = new TaskGroup();

    $group->spawn(fn() => throw new \RuntimeException("err 1"));
    $group->spawn(fn() => throw new \RuntimeException("err 2"));

    $group->seal();

    try {
        $group->any()->await();
    } catch (\Async\CompositeException $e) {
        echo count($e->getExceptions()) . " errors\n"; // "2 errors"
    }
});

Example #3 Resilient search with timeout ​

php
<?php

use Async\TaskGroup;

spawn(function() {
    $group = new TaskGroup();

    $group->spawn(fn() => searchGoogle($query));
    $group->spawn(fn() => searchBing($query));
    $group->spawn(fn() => searchDuckDuckGo($query));

    $timeout = Async\timeout(3.0);

    try {
        $result = $group->any()->await($timeout);
    } catch (Async\TimeoutException) {
        echo "No provider responded within 3 seconds\n";
    }

    $group->suppressErrors();
});

See Also ​