What is previous_release?

[Schrank]

I'm currently working on shopware/symfony deployment. In which I want to restart the message queue workers once the symlink is changed. previous_release sounds like the correct variable, but it ignores rollbacks and aborted releases.

Is this intended behaviour or a bug? If it is the last, I'm happy to fix it.

[LeandroCustodio2002]

Doesn’t look like a bug to me. Looking at recipe/deploy/release.php, previous_release is just releases_list[1], which is the release created before the current one. It doesn’t check where current points or the BAD_RELEASE/DIRTY_RELEASE markers, so after a rollback or a failed deploy it can point to a release that wasn’t actually live.

If you need the release that was actually live, capture current before the symlink switch:

before('deploy:symlink', function () {
    if (test('[ -L {{current_path}} ]')) {
        set('live_release_before', run('readlink -f {{current_path}}'));
    }
});

after('deploy:symlink', function () {
    // restart workers / compare with get('live_release_before') here
    run('{{bin/php}} {{release_or_current_path}}/bin/console messenger:stop-workers');
});

For restarting Messenger workers specifically you don’t even need the previous path: messenger:stop-workers after deploy:symlink is enough, and your supervisor will restart them from the new current.

[Schrank]

If this was thought through, when it was implemented, what is the intended behaviour? Because I can't imagine a case, where I want the previous_release instead of the "one which was last live".

Beside that, I learned from AI, that stopping workers works through setting a cache key... which only works if I write it to the correct cache directory, aka the old one?

https://github.com/symfony/messenger/blob/v7.4.18/EventListener/StopWorkerOnRestartSignalListener.php#L25-L37

So I'm currently not convinced, it is intended behaviour instead of "accidentally implemented like this without thinking it through" 🙈

[antonmedv]

I think the release_or_current_path is a corrent path for this kind of worker restart.

[Schrank]

I want to restart the worker after switching the symlink. But I interpret it, that we don't want to change previous_release to be as I expect it - which is no problem at all :-)
Then I'll implement something which reads the release list, to make sure it works not only during deployment, but always.

Thanks @antonmedv and @LeandroCustodio2002 <3