Maintenance: Drop zammad.ready file from docker entrypoint.

[mgruner]

Zammad 6.3 will drop the var/ folder, so that no share is needed any more for it. That's a good chance to improve the container waiting in the docker compose context as well.

Rather than placing a file in the var share to signal readiness, we can simply call the rails stack and ask it to fail if migrations are pending. Other parts in the zammad-init container such as Translation.sync can happen later and are not a requirement for services to start. This will also reduce start time / upgrade downtime significantly.

zammad-helm will soon handle it in a similar way (see zammad/zammad-helm#243).

[monotek]

The initial idea behind this whole thing was to reduce logs with error messages during startup in docker-compose.

The helm chart should not use such file at all an do the right thing out of the box (restart the container if it can't reach one of it´s dependencies like postgres).

Maybe we can move to this pattern in docker-compose too?

[mgruner]

The initial idea behind this whole thing was to reduce logs with error messages during startup in docker-compose.

The PR provides such behaviours. The service containers will print a few lines like

waiting for init container to finish install or update...
waiting for init container to finish install or update...
waiting for init container to finish install or update...

Until everything is ready. And then they start up. No error messages! IMHO that is very user friendly behaviour, isn't it?

The helm chart should not use such file at all an do the right thing out of the box (restart the container if it can't reach one of it´s dependencies like postgres).

Maybe we can move to this pattern in docker-compose too?

It might be possible to control the restart policy of the containers somehow, but the current proposal is better IMHO: it uses less resources, and people are perhaps not used to restarting containers in such context than in k8s. It might also conflict with customizations that users made.

So I would suggest to stick with this proposal.

[mgruner]

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