Make "db/" into a volume inside the Docker container

[AP-Hunt]

What problem does this pull request solve?

Trello card: https://trello.com/c/KoHvaEUA/681-aws-m112-ecs-read-only-root-filesystem-configuration

AWS ECS docs [1] say that a file that exists in a directory that is subsequently marked as a volume will be copied to the host and remounted into the container.

This is necessary for us to do with the "db/" directory because the "db:migrate" Rake task writes to "db/schema.rb"

[1] https://docs.aws.amazon.com/AmazonECS/latest/developerguide/bind-mounts.html

Things to consider when reviewing

• Ensure that you consider the wider context.
• Does it work when run on your machine?
• Is it clear what the code is doing?
• Do the commit messages explain why the changes were made?
• Are there all the unit tests needed?
• Has all relevant documentation been updated?

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[lfdebrux]

This is necessary for us to do with the "db/" directory because the "db:migrate" Rake task writes to "db/schema.rb"

That's surprising, I would have thought that db:migrate would write to db/schema.rb only if there are any changes 🤔

Oh well

[AP-Hunt]

only if there are any changes

That is true. We saw this on forms-runner and it caused an error. We're porting the fix over here to stop that happening.

[lfdebrux]

only if there are any changes

That is true. We saw this on forms-runner and it caused an error. We're porting the fix over here to stop that happening.

Hmm. Ideally there shouldn't be changes to db/schema.rb from running db:migrate, as that indicates a configuration drift. Ideally any changes would have been committed to the main branch before the deploy.

[AP-Hunt]

Hmm. Ideally there shouldn't be changes to db/schema.rb from running db:migrate, as that indicates a configuration drift. Ideally any changes would have been committed to the main branch before the deploy.

That's .. concerning? Probably? We were seeing this in staging, and in review once we began running db:migrate and not just db:setup: govuk-forms/forms-runner@7d943ce

[lfdebrux]

Hmm. Ideally there shouldn't be changes to db/schema.rb from running db:migrate, as that indicates a configuration drift. Ideally any changes would have been committed to the main branch before the deploy.

That's .. concerning? Probably? We were seeing this in staging, and in review once we began running db:migrate and not just db:setup: alphagov/forms-runner@7d943ce

Yeah I saw that. It is concerning, but only slightly? Probably not something that needs to be fixed right this moment.