fix(migrations): skip non-directory entries under keyspaces/

[sureshkrishnan-ai]

TL;DR

migrations/cassandra/keyspaces/ holds README.md alongside the four keyspace directories, and execute_sqls.sh iterated over every entry, so README.md was treated as a keyspace and aborted the migration run. This guards both loops with [ -d ] so only directories are treated as keyspaces.

Additional Details

README.md was passed to migrate as x-migrations-table=README.md. The golang-migrate Cassandra driver reads the dot in that value as keyspace.table, so it tried to open a keyspace named README, which Cassandra lowercases:

Successfully initialized the db
SQL files pre-processed successfully
error: failed to open database: Keyspace 'readme' doesn't exist
Migration failed for /tmp/keyspaces/README.md

execute_sqls.sh then exits 1, which fails the cassandra-helm-nvcf-cassandra-migrations Helm hook job and leaves the cassandra release in a failed state.

The first loop also creates an empty /tmp/keyspaces/README.md directory on the way through, which is why the guard is applied to both loops rather than only the one that calls migrate. The [ -d ] form was chosen over a .dockerignore for *.md because it also covers any other non-directory file added to keyspaces/ later.

The four real keyspaces (api_keys_api, ess_api, nvcf_api, sis_api) are unaffected.

For the Reviewer

Single file, six lines, no behaviour change for directories.

This fixes defect 2 of #190 only. Defect 1 in that issue (the FROM bitnami/cassandra:5.0.6 base no longer resolving, since Bitnami withdrew their public catalog in Aug 2025) is deliberately not addressed here, because the right replacement looks like a maintainer decision rather than something to presume: bitnamilegacy/cassandra:5.0.5-debian-12-r7 builds and runs, but it is a version downgrade, and an internal mirror may be preferred. Happy to follow up with a PR once you indicate a direction.

For QA

Verified against the fixed image built with README.md present in keyspaces/:

--- loop with the [ -d ] guard (this PR):
  SKIP (not a dir): README.md
  keyspace: api_keys_api
  keyspace: ess_api
  keyspace: nvcf_api
  keyspace: sis_api
--- same loop without the guard (current main):
  keyspace: README.md          <- the bug
  keyspace: api_keys_api
  ...

End to end, against Cassandra 5.0.x running in a local k3d cluster: with README.md present in the build context the migrations hook job fails as quoted above; with the same image built from a context where README.md is removed, the job completes and the schema applies. This change makes the README.md-present case behave like the README.md-absent case.

bash -n migrations/cassandra/execute_sqls.sh is clean.

QA needed: no, beyond a normal migrations run.

Issues:

• Fixes migrations/cassandra cannot be built from a clean checkout: withdrawn base image, and keyspaces/README.md breaks the migration run #190

Checklist

• I am familiar with the Contributing Guidelines.
• I have signed off my commits for Developer Certificate of Origin (DCO) compliance.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

On tests: there is no existing test harness for the shell scripts under migrations/ (no BUILD target, no bats or shell test suite, and no migrations entry in tools/ci/subproject-validations.yaml), so there was no natural place to add one for a six-line guard. Happy to add coverage if you want a harness introduced, or to fold it into whatever you would prefer here.