Helpers for working with postgres
This script allows you to run any command with a fresh, ephemeral/single-use postgres database available. When the script starts a Dockerized postgres container starts-up, and when the script completes that container is removed.
The environment variable DB_POSTGRES_URL will be set with a connection string that can be used to connect to the database. The PG* environment variables that are recognized by libpq (i.e. used by the psql client) are also set.
Example
$ ./with-test-db.sh psql -c 'select 1;'
[+] Running 1/1
⠿ Container pg-db_test-1 Healthy 1.8s
?column?
----------
1
(1 row)
[+] Running 1/1
⠿ Container pg-db_test-1 Stopped 0.1s
Going to remove pg-db_test-1
[+] Running 1/0
⠿ Container pg-db_test-1 Removed
The Docker compose file can be used to run containerized versions of postgres either for single use (as is used by with-test-db.sh), or for longer-term use. These are setup as separate services named db_test and db respectively. In both cases the database is available on the host machine's localhost and credentials are:
- Username: pg
- Password: password
However, each service uses a different port, documented below, to avoid conflicts.
The single-use db_test service does not have any persistent storage. When the container is removed, data in the database disappears with it.
This service runs on port 5433.
$ docker compose up db_test # start container
$ docker compose stop db_test # stop container
$ docker compose rm db_test # remove container
The db service has persistent storage on the host machine managed by Docker under a volume named pg_atp_db. When the container is removed, data in the database will remain on the host machine. In order to start fresh, you would need to remove the volume.
This service runs on port 5432.
$ docker compose up db -d # start container
$ docker compose stop db # stop container
$ docker compose rm db # remove container
$ docker volume rm pg_atp_db # remove volume