Run Postgres using "docker-compose"

Create a local directory called "postgres"

$ mkdir postgres
$ cd ./postgres

Create a "pgdata" directory inside "postgres" directory

$ cd ./postgres
$ mkdir ./pgdata

👉 As a docker container is "stateless" we must create the directory "pgdata" to keep the data when the container is shut down.

Create a file called "docker-compose.yml" in "postgres" directory

$ touch ./docker-compose.yml

📄 docker-compose.yml file

version: "3.8"
services:
  db:
    image: "postgres:13"
    ports:
      - "5432:5432"
    volumes:
      - ./pgdata:/var/lib/postgresql/data
    environment:
      - POSTGRES_USER=dbuser
      - POSTGRES_PASSWORD=admin2021
      - POSTGRES_DB=todoapp

• This file creates a host called "db" from a Postgres version 13 image. The TCP port 5432 (postgres) of the host "db" is exposed externally as TCP port 5432.

• The local directory "./pgdata" is mapped as "/var/lib/postprogressql/data" inside the "db" host

• The username, password and database name are exposed as an environment variable

Run the container in detached mode

$ docker-compose up -d

List of running docker containers

$ docker-compose ps

Run command inside the container

$ docker-compose run db bash

Connect postgres inside the host

$ psql  --host=db --username=dbuser --dbname=todoapp

Connect to "postgres" from outside

$ psql --host=localhost --username=dbuser --dbname=todoapp

stop container

$ docker-compose down

Et voilà 🎉 !