Autowire ServiceLocator with iterable of tagged services #39924

zmitic · 2021-01-21T17:17:39Z

Description

Use attributes to have autowiring between ServiceLocator and tagged services, by key that can be either FQCN (default) or allow users to define it. Upgrade of implementation: #29203

Example of FQCN index, along with psalm annotation use:

class MyService
{
    public function __construct(
        #[Tagged(name: 'form.type')] private ServiceLocator $tagged
    ) {}
    
    /**
    * @param class-string<FormTypeInterface> $className
    */
    public function get(string $className): FormTypeInterface
    {
        return $this->tagged->get($className);
    }
}

$formType = $myService->get(EntityType::class);

If users want different index (like #29203), optional parameter would be the name of static method used:

interface ExporterInterface
{
    public static function getName(): string;
}

class CSVExporter implements ExporterInterface
{   
    public static function getName(): string
    {
        return 'csv_exporter';
    }
}

class MyService
{
    public function __construct(
        #[Tagged(name: 'app.exporter', indexMethod: 'getName')] private ServiceLocator $tagged
    ) {}
    
    public function get(string $name): ExporterInterface
    {
        return $this->tagged->get($name);
    }
}

$exporter = $myService->get('csv_exporter'); // this would be instance of CSVExporter

If of any relevance, stub for ServiceLocator can be this:

/** 
 * @template T
 */
class ServiceLocator
{
    /** @return T */
    public function get($id){}
}

zmitic · 2021-01-21T17:51:58Z

Best case would be to allow interface usage instead of string-based tag names:

class MyService
{
    public function __construct(
        #[TaggedInterface(FormTypeInterface::class)] private ServiceLocator $tagged
    ) {}
    
    /**
    * @param class-string<FormTypeInterface> $className
    */
    public function get(string $className): FormTypeInterface
    {
        return $this->tagged->get($className);
    }
}

$formType = $myService->get(EntityType::class);

A feature like this could be useful for a day we get generics; tools like rector might provide automigration:

public function __construct(private ServiceLocator<FormTypeInterface> $tagged)

nicolas-grekas · 2021-01-21T17:59:29Z

#[Tagged(name: 'form.type')]

This looks like just one step after #39897 - could happen in 5.3 :)

#[TaggedInterface(FormTypeInterface::class)]

I would clearly advise against this. It's a shortcut that forgets that tags are absolutely required as intermediaries to create collections of services in a decoupled way.

But fortunately, together with #39804, you might end up being able to provide a very similar DX.

zmitic · 2021-01-21T18:12:15Z

I would clearly advise against this.

That is OK. My tagged services have same name as interface i.e.

$container->registerForAutoconfiguration(ExporterInterface::class)->addTag(ExporterInterface::class);

so I thought to maybe even remove this one line. But yes, it might be too much, sorry.

nicolas-grekas · 2021-06-21T14:22:25Z

PR welcome @zmitic

zmitic · 2021-06-21T14:46:30Z

@nicolas-grekas For #[TaggedInterface]?

If so; would I be allowed to create another class instead of ServiceLocator, and add stubs like in the first comment?

nicolas-grekas · 2021-06-21T14:54:43Z

For #[Tagged(name: 'form.type')] (see above about #[TaggedInterface])

derrabus added DependencyInjection Feature labels Jan 21, 2021

symfony / symfony

Autowire ServiceLocator with iterable of tagged services #39924

Autowire ServiceLocator with iterable of tagged services #39924

zmitic commented Jan 21, 2021 •

edited

zmitic commented Jan 21, 2021

nicolas-grekas commented Jan 21, 2021 •

edited

zmitic commented Jan 21, 2021

nicolas-grekas commented Jun 21, 2021

zmitic commented Jun 21, 2021

nicolas-grekas commented Jun 21, 2021

symfony / symfony

Sponsor symfony/symfony

Autowire ServiceLocator with iterable of tagged services #39924

Autowire ServiceLocator with iterable of tagged services #39924

Comments

zmitic commented Jan 21, 2021 • edited

zmitic commented Jan 21, 2021

nicolas-grekas commented Jan 21, 2021 • edited

zmitic commented Jan 21, 2021

nicolas-grekas commented Jun 21, 2021

zmitic commented Jun 21, 2021

nicolas-grekas commented Jun 21, 2021

zmitic commented Jan 21, 2021 •

edited

nicolas-grekas commented Jan 21, 2021 •

edited