Use rake db:migrate:status to check for pending migrations

This is a small rewrite of the database migrations trigger. Instead of comparing the gitlab-rails version we can look for pending database migrations.

The reason I did not do something like this way back when I worked on this code is that starting rake is slow, and now this will happen on every reconfigure.

Maybe it is worth it. I just wanted to point this out.

Maybe it is slow but it will solve issues when for whatever reason a db migration was not done before even if we already are on the same version.

@jacobvosmaer Yup, this was my comment as well so trying to see if we can do this better or if the can live with the slowness. It would be so much easier if we can just connect to the database and look at the schema_migrations table and if it doesn't match the db/schema.rb version trigger a migration...

Actually, there is some room to improve this without loading rake task or going into the db.

I think we could adapt migrate_database definition and pipe the result of the run to a file. On next reconfigure run we can just check if the file has the expected value, if not run the migration again.

Still I think we are looking for a faster solution which will never be so solid as rake db:migrate:status, for the record the command will run for real 0m11.745s.

Or if 11 seconds is really too long we can simple add the commit hash in VERSION as well.

@jnijhof That is correct, we won't find as solid solution as db:migrate:status. The time is highly dependent on the environment, for me this showed real 0m18.063s on a VM, it is safe to assume this varies based on the machine. We have other tasks that we run so we need to be careful to not make the reconfigure run very slow. For this specific case we still have options so lets see if we can use those first :)

mentioned in merge request !700 (merged)

closing in favor of !700 (merged)

Status changed to closed

mentioned in commit 3b42520a