backend: Add migration down support

[yolossn]

No description provided.

[yolossn]

The migrate-down flag should be used to remove the last migrations before reverting to an old version of Nebraska. One question still remains, how will the admin know how many migrations should be reverted ? Should we start adding the migrations introduced along with the releases going on ? @joaquimrocha thoughts ?

[joaquimrocha]

The migrate-down command should be used to remove the last migrations before reverting to an old version of Nebraska. One question still remains, how will the admin know how many migrations should be reverted ? Should we start adding the migrations introduced along with the releases going on ? @joaquimrocha thoughts ?

I think maybe we can an argument support to migrate-down, so users can do: --migrate-down=004 (exclusive, i.e. down to 004 which will be the last migration applied applied).

Users can use git to get the last migration for a past version:
git show 2.4.0:./backend/pkg/api/db/migrations | tail -n1

Alternatively we could add a command called db-migrate with the following options:
nebraska db-migrate --down-to=004: this migrations down till a migration starting with 004 (this one is not migrated down, i.e. it's exclusive)
nebraska db-migrate --show: this lists the current migrations for the current version.

(but this command would only be available in new versions, so maybe it's not so useful when users have git)

WDYT?

[yolossn]

Makes sense to use the migration id for migrate down, I will add the documentation for the same.

[yolossn]

Added docs for migrating to an older version of Nebraska.

[illume]

A test for verifying migrations down work would be useful.

[yolossn]

Added test 👍🏽

[illume]

Added test 👍🏽

Awesome. Thanks!

[joaquimrocha]

Found an issue in the docs.
BTW, --migrate-down-to sounds a bit complicated and is unrelated to DBs. Should we rename it as --migrate-db-to and support migrating up as well? (maybe in the beginning we can just support migrating down, but it's important that the command name makes sense)

[joaquimrocha]

I think this article is a bit confusing. The command associated with this phrase doesn't necessarily show the newly added files in this folder for this tag, it just lists the contents of that dir, for that tag (so it is the same result for 2.4.1).

It should instead say that if users want to migrate to a version, like 2.4.0, they should run the command you wrote (gets them the last migration considered in 2.4.0) and run the --migrate-down-to 0013.

[yolossn]

--migrate-down-to sounds a bit complicated and is unrelated to DBs.

Does rollback-db-to make sense ?

Sorry I misunderstood the git show part from your previous comment, Ill update the docs accordingly.

[joaquimrocha]

Left a comment about the command's name. Also, I don't think the docs were updated.