🛢️ docker-postgres

supposed Docker is installed

PostgreSQL Docker Setup

A lightweight and official PostgreSQL container (Alpine) with automatic initialization, correct permissions handling, and ready-to-use configuration

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🔑 Magic Key Explanation

In the docker-compose.yml, this crucial line is :

entrypoint: ["/bin/sh", "-c", "chown -R postgres:postgres /var/lib/postgresql/data && exec docker-entrypoint.sh postgres"]

➡️ This line executes before startup :

chown -R postgres:postgres /var/lib/postgresql/data

→ Give the correct permissions to the postgres user on the volume (even if it was created as root)

exec docker-entrypoint.sh postgres

→ then run the real official initialization script.

✅ Résult :

No need for user : no manual chmod.

The image remains official and light (Alpine).

Works immediately on the first launch.

CLI

Run container :

docker-compose up -d

Check postgresql database docker image and the inserted data :

docker exec -i postgres_container psql -U postgres_user -d postgres_db < upsert_users.sql

docker exec -it postgres_container psql -U postgres_user -d postgres_db -c "SELECT * FROM users;"

In terminal, result like this:

id |  name  |        email         
----+--------+---------------------
  1 | Alice  | alice@example.com
  2 | Bob    | bob@example.com
  3 | Franck | franck@example.com
  4 | Diana  | diana@example.com
(4 rows)

Connection from a local client

Example (Adminer, DBeaver, psql…) :

• Host : localhost
• Port : 5432 (by default, not exposed, accessible by the Docker network)
• Database : postgres_db
• User : postgres_user
• Password : password

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If needed to start from scratch the database, run this command before the docker-compose up (this, will delete volume) :

docker-compose down -v