Fix two follow-on issues reported when starting the dev stack with
docker-compose-mysql.yml:
1. ``superset-init`` step 4 (load-examples) fails with
``MySQLdb.OperationalError: (2002, "Can't connect to server on 'db'")``
because the analytics-examples DB connection inherits ``EXAMPLES_PORT=5432``
(Postgres port) from ``docker/.env``. The override flipped
``DATABASE_DIALECT`` to ``mysql+mysqldb`` but left the EXAMPLES_*
group on Postgres defaults, so the URI became
``mysql+mysqldb://examples:examples@db:5432/examples`` — MySQL
container has no listener on 5432.
Fix: add ``EXAMPLES_HOST/PORT/DB/USER/PASSWORD`` and a complete
``SUPERSET__SQLALCHEMY_EXAMPLES_URI`` to the ``mysql-env`` anchor.
2. The Postgres init scripts under
``docker/docker-entrypoint-initdb.d/`` (``cypress-init.sh``,
``examples-init.sh``) get mounted on the MySQL container too —
compose merges volume lists. They invoke ``psql`` which doesn't
exist in the MySQL image, abort with ``psql: command not found``,
and prevent the ``examples`` DB from being created.
Fix: add a MySQL-specific init script
``docker/mysql-init/examples-init.sql`` that creates the
``examples`` database and user, and mount it at
``/docker-entrypoint-initdb.d`` in the override. Compose's
later-takes-precedence rule on duplicate volume targets displaces
the Postgres init dir, so the MySQL container only sees the
MySQL-compatible script.
(Used a plain duplicate-target mount rather than the ``!override``
tag because pre-commit's ``check-yaml`` doesn't recognize Compose's
custom YAML tags.)
Recovery for an existing failed MySQL stack: ``docker compose -f
docker-compose.yml -f docker-compose-mysql.yml down``, then
``docker volume rm superset_db_home_mysql`` (so the new init script
runs on the next fresh boot), then ``up`` again.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
