infra-role-postgres-ha/tasks/databases.yml

---
- name: 'Create user: {{ db.get("user", db.name) }}'
  command: >
    docker exec {{ postgres_ha_cont_name }}
      psql
        --username={{ postgres_ha_admin_user }}
        --port={{ postgres_ha_cont_port }}
        --command
      "DO $$
      BEGIN
        CREATE USER \"{{ db.get("user", db.name) }}\" PASSWORD '{{ db.pass | mandatory }}';
        EXCEPTION WHEN DUPLICATE_OBJECT THEN
        RAISE NOTICE 'not creating role {{ db.get("user", db.name) }} -- it already exists';
      END
      $$;"

- name: 'Create database: {{ db.name | mandatory }}'
  shell: >
    echo "SELECT
        'CREATE DATABASE \"{{ db.name }}\" WITH OWNER \"{{ db.get("user", db.name) }}\";'
        WHERE NOT EXISTS (SELECT FROM pg_database WHERE datname = '{{ db.name }}')\\\gexec" |
    docker exec -i {{ postgres_ha_cont_name }} \
      psql \
        --username={{ postgres_ha_admin_user }} \
        --port={{ postgres_ha_cont_port }}