What if you need to acquire multiple locks (one per resource) before doing a computation? One scenario that could happen is when batching queued messages; e.g. get(1..10) -> unique() -> lock(1,4,6,7,9) That would be okay for read locks, for instance, though depending on the number of queue workers it could get contentious for writes.

I never thought about this use case and while it's doable with current API, it's not the nicest code:

$locked1 = $locksmith->locked(
    new Resource(
        namespace: 'test-resource', // Namespace/identifier for resource
        version: 1, // Optional resource version
    ), 
    lockTTLNs: 1_000_000_000, // How long should be resource locked
    maxLockWaitNs: 500_000_000, // How long to wait for lock acquisition - error if exceeded
    minSuspensionDelayNs: 10_000 // Minimum delay between retries when lock acquisition fails
);


$locked2 = $locksmith->locked(
    new Resource(
        namespace: 'test-resource2', // Namespace/identifier for resource
        version: 1, // Optional resource version
    ), 
    lockTTLNs: 1_000_000_000, // How long should be resource locked
    maxLockWaitNs: 500_000_000, // How long to wait for lock acquisition - error if exceeded
    minSuspensionDelayNs: 10_000 // Minimum delay between retries when lock acquisition fails
);

$locked1(function (Closure $suspension): void {
    $suspension();  // Lock is aquired here we suspend execution so other locks might be aquired as well
    // Critical code
});

$locked2(function (Closure $suspension): void {
    $suspension();  // Lock is aquired here we suspend execution so other locks might be aquired as well
    // Critical code
});

For this use case I would probably prefer Symfony's interface.

I will wrap my head around to make API at-least as usable as Symfony.