Checking for the database to be ready

[jogobeny]

Sometimes I get this error:

(txmatching) [jogobeny@archlinux txmatching]$ make setup-small-non-empty-db
make setup-empty-db
make[1]: Entering directory '/home/jogobeny/Documents/txmatching'
docker-compose stop db || true
[+] Running 1/0
 ⠿ Container txmatching-db-1  Stopped                                                                                                                                                                    0.0s
docker-compose rm -f db || true
Going to remove txmatching-db-1
[+] Running 1/0
 ⠿ Container txmatching-db-1  Removed                                                                                                                                                                    0.0s
docker volume rm txmatching_txmatching-postgres || true
txmatching_txmatching-postgres
docker-compose up -d db
[+] Running 2/2
 ⠿ Volume "txmatching_txmatching-postgres"  Created                                                                                                                                                      0.0s
 ⠿ Container txmatching-db-1                Started                                                                                                                                                      1.0s
sleep 2
make migrate-db
make[2]: Entering directory '/home/jogobeny/Documents/txmatching'
cd txmatching && PYTHONPATH=${PYTHONPATH:-..} POSTGRES_USER=super-cool-txmatching POSTGRES_PASSWORD=super-secret-pwd POSTGRES_DB=txmatching POSTGRES_URL=localhost:5432 python database/migrate_db.py
Traceback (most recent call last):
  File "/home/jogobeny/Documents/txmatching/txmatching/database/migrate_db.py", line 60, in <module>
    migrate_db()
  File "/home/jogobeny/Documents/txmatching/txmatching/database/migrate_db.py", line 43, in migrate_db
    backend = get_backend(acceptable_db_uri)
  File "/home/jogobeny/.conda/envs/txmatching/lib/python3.10/site-packages/yoyo/connections.py", line 99, in get_backend
    backend = backend_class(parsed, migration_table)
  File "/home/jogobeny/.conda/envs/txmatching/lib/python3.10/site-packages/yoyo/backends.py", line 165, in __init__
    self._connection = self.connect(dburi)
  File "/home/jogobeny/.conda/envs/txmatching/lib/python3.10/site-packages/yoyo/backends.py", line 706, in connect
    return self.driver.connect(**kwargs)
  File "/home/jogobeny/.conda/envs/txmatching/lib/python3.10/site-packages/psycopg2/__init__.py", line 122, in connect
    conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
psycopg2.OperationalError: connection to server at "localhost" (::1), port 5432 failed: FATAL:  the database system is starting up

Maybe we can add checking for the database to be ready?

https://stackoverflow.com/questions/62904304/psycopg2-operationalerror-fatal-the-database-system-is-starting-up-docker

https://www.postgresql.org/docs/current/app-pg-isready.html