ETT-44: Use env vars for database config

[aelkiss]

@Ronster2018 Mainly just want to check that this is looking the way you'd expect both in docker-compose.yml and that it matches what you'd expect given https://hathitrust.atlassian.net/wiki/spaces/ETT/pages/3489759233/Database+Credentials+in+Kubernetes

[aelkiss]

@Ronster2018 I'll have a corresponding ht_tanka pull request as well soon.

[coveralls]

coverage: 98.808% (-0.002%) from 98.81%
when pulling f550a54 on ETT-44-database-config
into 76040e9 on main.

[aelkiss]

Tests succeeded; I think the minimal coverage decrease isn't a problem.

[Ronster2018]

Here, we don't need to duplicate the work being brought in from the fragment template above. It looks like the only difference here is the MARIADB_HT_RO_HOST section on line 39 which can be overwritten. I made the following changes locally and here is what I would suggest:

line 19: add &environment anchor
line 37: add <<: *environment alias
line 39: Keep MARIADB_HT_RO_HOST: mariadb-test

to test and check the output in the terminal to make sure things look right, run docker compose -f docker-compose.yml config

  environment: &environment
    REDIS_URL: redis://redis/
    PREVIEW_EMAIL: true
    MARIADB_HT_RO_HOST: mariadb-dev
    MARIADB_HT_RO_USERNAME: datasets
    MARIADB_HT_RO_PASSWORD: datasets
    MARIADB_HT_RO_DATABASE: ht

services:

  test:
    <<: *common-service
    restart: never
    command: bundle exec rspec
    depends_on:
      redis: *healthy
      mariadb-test: *healthy
    environment:
      <<: *environment
      MARIADB_HT_RO_HOST: mariadb-test

[aelkiss]

Thanks, I'll give that a try!

[aelkiss]

This looks like it should work. Once tests pass I'll go ahead and merge.