[Contracts][DependencyInjection] Add `ServiceCollectionInterface` #53163

kbond · 2023-12-20T18:28:23Z

Q	A
Branch?	7.1
Bug fix?	no
New feature?	yes
Deprecations?	no
Issues	n/a
License	MIT

I commonly require a service locator which is also an iterator. I noticed during @weaverryan's most recent livestream he could have benefited from this as well. There are currently three ways to achieve:

Decorate a ServiceLocator and use ServiceLocator::getProvidedServices() in the decorator's getIterator()
Decorate a service iterable and add your own ContainerInterface::get() method which iterates over all items until it finds a match (this is what Ryan did in his livestream)
Inject a tagged iterator in addition to your locator.

This PR proposes a new ServiceCollectionInterface which is a countable, iterable, ContainerInterface.

I'm implemented on the current ServiceLocator so any place this is used in your code, you can now type-hint ServiceCollectionInterface:

public function someAction(
    #[TaggedLocator('some.tag')]
    ServiceCollectionInterface $container,
) {
    foreach ($container as $id => $item) {
        // do something with each service/id
    }

    $container->count(); // # of services
    
    $container->get('some.id');
}

src/Symfony/Component/DependencyInjection/ServiceCollectionInterface.php

GromNaN

I commonly require a service locator which is also an iterator.

Could you provide examples where you need the service locator to be iterable. Maybe a link to the video with a point in time where "he could have benefited from this".

src/Symfony/Component/DependencyInjection/ServiceLocator.php

kbond · 2023-12-20T19:24:08Z

Could you provide examples where you need the service locator to be iterable.

Here's a good example: https://github.com/symfony/ux/pull/1347/files#diff-6487ef7c39e106956904930b49958df26d90de6e025cd0c69a1a9a84e31ed064 (the entire class could be replaced with a ServiceLocator). He needs to iterate over a collection of component services for the index page, then, on each component page, he needs to get a specific one.

kbond · 2023-12-20T21:37:31Z

Ok, I've removed the interface and just made ServiceLocator iterable.

derrabus · 2023-12-21T08:55:27Z

There are currently two ways to achieve:

Inject a tagged iterator in addition to your locator.

derrabus · 2023-12-21T09:02:12Z

src/Symfony/Component/DependencyInjection/ServiceLocator.php

+        foreach (array_keys($this->getProvidedServices()) as $id) {
+            yield $id => $this->get($id);
+        }


This basically means that by iterating over the locator you initialize all of its services. To me, this kinda defeats the purpose of a service locator: I could've just injected a tagged iterator and called iterator_to_array() on it.

If we really want to make the locator traversable (not sure if we should yet), maybe we'd rather yield a service closure instead?

but because this is a generator, this still does it kinda lazily so it's OK?

I don't know, this still looks like a pitfall to me. I wouldn't do it.

@kbond WDYT of this concern? I don't feel the need for this extra safety myself but maybe your experience could help best decide?

I don't know, this still looks like a pitfall to me. I wouldn't do it.

Does the new interface alleviate the concern at all?

src/Symfony/Component/DependencyInjection/ServiceLocator.php

nicolas-grekas

The added method is just a helper: userland can do this iteration with any ServiceProviderInterface.

IoC principle would encourage using the interface.

Still worth it?

nicolas-grekas · 2023-12-21T09:47:11Z

symfony/ux#1347 (files) (the entire class could be replaced with a ServiceLocator)

that's quite common needless overhead - we already simplified many components by using a container
this PR is not needed to kill that class :)

kbond · 2023-12-22T01:41:58Z

that's quite common needless overhead - we already simplified many components by using a container
this PR is not needed to kill that class :)

I guess you mean, inject a tagged iterator into the index action and the tagged locator into the show method? Indeed that would work.

The added method is just a helper: userland can do this iteration with any ServiceProviderInterface.

This is true, and in fact what I've been doing, but in userland, ServiceProviderInterface::getProvidedServices() is weird. It's keyed by the service id which, imo, is 95% of the reason to call by end users (the array values aren't important at this stage). It's a bit of a papercut imo as I don't think it's entirely clear this is possible (iterating over all the services).

What about a ServiceProviderInterface::getProvidedServiceIds(): string[] method?

Still worth it?

I do still feel this improves the DX as the need for a service locator/iterator is a common pattern I'm seeing (but let's close if there isn't agreement).

nicolas-grekas · 2023-12-26T15:02:56Z

To make this full "IoC", one can type hint ServiceProviderInteface&Traversable, isn't it? Then LGTM.

kbond · 2023-12-26T16:19:57Z

As discussed with Nicolas on Slack, I've switched back to a ServiceCollectionInterface (in symfony/service-contracts).

nicolas-grekas

Works for me, thanks.
Please update the root composer.json for 3.5 also.

kbond · 2023-12-28T16:10:03Z

Please update the root composer.json for 3.5 also.

Done, but please confirm it's updated correctly.

src/Symfony/Component/DependencyInjection/ServiceLocator.php

chalasr · 2024-01-02T14:18:05Z

Thank you @kbond.

carsonbot added Status: Needs Review DependencyInjection Feature labels Dec 20, 2023

carsonbot added this to the 7.1 milestone Dec 20, 2023

kbond force-pushed the feat/service-collection-interface branch from b801081 to 18cf8fe Compare December 20, 2023 18:30

stof reviewed Dec 20, 2023

View reviewed changes

src/Symfony/Component/DependencyInjection/ServiceCollectionInterface.php Outdated Show resolved Hide resolved

kbond force-pushed the feat/service-collection-interface branch from 18cf8fe to 6e48c4c Compare December 20, 2023 18:38

ro0NL reviewed Dec 20, 2023

View reviewed changes

src/Symfony/Component/DependencyInjection/ServiceCollectionInterface.php Outdated Show resolved Hide resolved

GromNaN reviewed Dec 20, 2023

View reviewed changes

src/Symfony/Component/DependencyInjection/ServiceLocator.php Outdated Show resolved Hide resolved

kbond force-pushed the feat/service-collection-interface branch from 6e48c4c to ca47fd0 Compare December 20, 2023 21:35

kbond changed the title ~~[DependencyInjection] Introduce ServiceCollectionInterface~~ [DependencyInjection] Make ServiceLocator iterable Dec 20, 2023

kbond force-pushed the feat/service-collection-interface branch from ca47fd0 to 8db521a Compare December 20, 2023 21:43

yceruto approved these changes Dec 21, 2023

View reviewed changes

carsonbot added Status: Reviewed and removed Status: Needs Review labels Dec 21, 2023

derrabus reviewed Dec 21, 2023

View reviewed changes

nicolas-grekas reviewed Dec 21, 2023

View reviewed changes

src/Symfony/Component/DependencyInjection/ServiceLocator.php Outdated Show resolved Hide resolved

nicolas-grekas reviewed Dec 21, 2023

View reviewed changes

kbond force-pushed the feat/service-collection-interface branch from 8db521a to 33d14d0 Compare December 26, 2023 16:09

kbond changed the title ~~[DependencyInjection] Make ServiceLocator iterable~~ [DependencyInjection] Add ServiceCollectionInterface Dec 26, 2023

kbond added the Contracts label Dec 26, 2023

carsonbot changed the title ~~[DependencyInjection] Add ServiceCollectionInterface~~ [Contracts][DependencyInjection] Add ServiceCollectionInterface Dec 26, 2023

nicolas-grekas approved these changes Dec 27, 2023

View reviewed changes

kbond force-pushed the feat/service-collection-interface branch from 33d14d0 to a47e84f Compare December 28, 2023 16:09

kbond force-pushed the feat/service-collection-interface branch from a47e84f to 578a99a Compare December 28, 2023 16:34

nicolas-grekas approved these changes Dec 28, 2023

View reviewed changes

chalasr approved these changes Dec 29, 2023

View reviewed changes

xabbuh reviewed Jan 1, 2024

View reviewed changes

src/Symfony/Component/DependencyInjection/ServiceLocator.php Outdated Show resolved Hide resolved

[DependencyInjection] Add ServiceCollectionInterface

4a9e874

kbond force-pushed the feat/service-collection-interface branch from 578a99a to 4a9e874 Compare January 2, 2024 14:07

chalasr merged commit 82e0eff into symfony:7.1 Jan 2, 2024

chalasr mentioned this pull request Jan 2, 2024

[Contracts][DependencyInjection] Add ServiceCollectionInterface symfony/symfony-docs#19368

Closed

fabpot mentioned this pull request May 2, 2024

Release v7.1.0-BETA1 #54820

Merged

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

[Contracts][DependencyInjection] Add `ServiceCollectionInterface` #53163

[Contracts][DependencyInjection] Add `ServiceCollectionInterface` #53163

kbond commented Dec 20, 2023 •

edited

Loading

GromNaN left a comment

kbond commented Dec 20, 2023 •

edited

Loading

kbond commented Dec 20, 2023

derrabus commented Dec 21, 2023

derrabus Dec 21, 2023

nicolas-grekas Dec 21, 2023

derrabus Dec 21, 2023

nicolas-grekas Dec 26, 2023

kbond Dec 26, 2023

nicolas-grekas left a comment

nicolas-grekas commented Dec 21, 2023

kbond commented Dec 22, 2023 •

edited

Loading

nicolas-grekas commented Dec 26, 2023

kbond commented Dec 26, 2023

nicolas-grekas left a comment

kbond commented Dec 28, 2023

chalasr commented Jan 2, 2024

[Contracts][DependencyInjection] Add ServiceCollectionInterface #53163

[Contracts][DependencyInjection] Add ServiceCollectionInterface #53163

Conversation

kbond commented Dec 20, 2023 • edited Loading

GromNaN left a comment

Choose a reason for hiding this comment

kbond commented Dec 20, 2023 • edited Loading

kbond commented Dec 20, 2023

derrabus commented Dec 21, 2023

derrabus Dec 21, 2023

Choose a reason for hiding this comment

nicolas-grekas Dec 21, 2023

Choose a reason for hiding this comment

derrabus Dec 21, 2023

Choose a reason for hiding this comment

nicolas-grekas Dec 26, 2023

Choose a reason for hiding this comment

kbond Dec 26, 2023

Choose a reason for hiding this comment

nicolas-grekas left a comment

Choose a reason for hiding this comment

nicolas-grekas commented Dec 21, 2023

kbond commented Dec 22, 2023 • edited Loading

nicolas-grekas commented Dec 26, 2023

kbond commented Dec 26, 2023

nicolas-grekas left a comment

Choose a reason for hiding this comment

kbond commented Dec 28, 2023

chalasr commented Jan 2, 2024

[Contracts][DependencyInjection] Add `ServiceCollectionInterface` #53163

[Contracts][DependencyInjection] Add `ServiceCollectionInterface` #53163

kbond commented Dec 20, 2023 •

edited

Loading

kbond commented Dec 20, 2023 •

edited

Loading

kbond commented Dec 22, 2023 •

edited

Loading