Add priority field to processor tags

[HypeMC]

Q	A
Branch?	3.x
Bug fix?	no
New feature?	yes
Deprecations?	no
Issues	-
License	MIT

Continuation of #455.

Foo\Bar\Log\Processors\FirstProcessor:
    tags:
        - { name: monolog.processor, channel: http }

Foo\Bar\Log\Processors\SecondProcessor:
    tags:
        - { name: monolog.processor, channel: http, priority: -10 } # last

Foo\Bar\Log\Processors\ThirdProcessor:
    tags:
        - { name: monolog.processor, channel: http, priority: -20 } # very last

#[AsMonologProcessor(priority: -10)]
class SecondProcessor {}

#[AsMonologProcessor(priority: -20)]
class ThirdProcessor {}

Probably better to review with whitespace changes ignored.

[alexndlm]

@stof @derrabus Can we have this merged and released? This is an extremely needed feature.

[derrabus]

@alexndlm Did you review and test the change in your projects? I agree that we should try to get it merged.

[alexndlm]

Of course not, I have unlimited trust in Symfony 😎 But I will do this soon to double-check.

[derrabus]

But I will do this soon to double-check.

Thank you! I personally don't need this feature at the moment. So getting feedback from someone who'd actually use it is more than valuable to us.

[nicolas-grekas]

Looks like PR is needed for symfony/symfony#54445?

[stof]

@nicolas-grekas no. this PR does not affect the Symfony PR (see my comment on the Symfony PR)

[alexndlm]

@derrabus I have tested it, and it works perfectly

[alexndlm]

@derrabus, my bad, it does not work; I have found one issue.

When we add some processor only for channel app with the lowest priority, it will always be first. This is because in \Symfony\Bundle\MonologBundle\DependencyInjection\Compiler\AddProcessorsPass for the app channel, we use monolog.logger, and when there is no channel, we use monolog.logger_prototype.

And in symfony/monolog-bundle/Resources/config/monolog.xml the monolog.logger has parent monolog.logger_prototype.

So, when DI create monolog.logger service, it first calls push pushProcessor for monolog.logger_prototype and then calls for monolog.logger.

The same issue should be for any channel.

[alexndlm]

@HypeMC, do you have time to fix this?

[HypeMC]

When we add some processor only for channel app with the lowest priority, it will always be first. This is because in \Symfony\Bundle\MonologBundle\DependencyInjection\Compiler\AddProcessorsPass for the app channel, we use monolog.logger, and when there is no channel, we use monolog.logger_prototype.

And in symfony/monolog-bundle/Resources/config/monolog.xml the monolog.logger has parent monolog.logger_prototype.

So, when DI create monolog.logger service, it first calls push pushProcessor for monolog.logger_prototype and then calls for monolog.logger.

The same issue should be for any channel.

@alexndlm Sorry for the late reply, I missed your feedback. The issue should be fixed with 1ad6fc7.

[GromNaN]

LGTM, with some improvement that can be done later.

[GromNaN]

The compiler passes should be stateless. We can add a tag to the logger definitions so that we can retrieve them with $container->findTaggedServiceIds('monolog.channel_logger')

[GromNaN]

Nit: you can combine else and if into elseif