Prerequisites

  • Docker
  • Docker Compose (Optional)

If you didn’t install them already look at these links:

You can check them via:

$ docker -v
Docker version 19.03.13, build 4484c46d9d

$ docker-compose -v
docker-compose version 1.23.2, build 1110ad01

Build Container

Execute below command to create a PostgreSQL container:

$ docker run -d -p 5432:5432 --name localpostgres -e POSTGRES_PASSWORD=secretpassword postgres:11.6

This command will download Postgres 11.6 from Docker Postgre Hub.

If we look in detail:

  • -d : means run in detached mode,
  • --name : we give container a name : localpostgres,
  • -e : environment variable;
  • postgres:11.6 : is our main image that we create the container upon

Info

I use PostgreSQL version 11.6 since I have it already but you can use whatever version you want.

Also if you leave tag blank docker will fetch the latest version.

However I definitely don’t recommend that since it may break your software stack.

Get Into the Container

After creating the container we can access it on our host:

$ docker exec -it localpostgres bash

root@6542951f176a:/# psql -U postgres
psql (11.6 (Debian 11.6-1.pgdg90+1))
Type "help" for help.

postgres=#

Use the Container

Create a Database

We will create a database inside our PostgreSQL container:

root@cb9222b1f718:/# psql -U postgres
psql (11.6 (Debian 11.6-1.pgdg90+1))
Type "help" for help.

postgres=# CREATE DATABASE testdb;
CREATE DATABASE
postgres=#

Create a Table

Let’s create an example table inside our testdb:

postgres=# CREATE TABLE accounts (
 user_id serial PRIMARY KEY,
 username VARCHAR ( 50 ) UNIQUE NOT NULL,
 password VARCHAR ( 50 ) NOT NULL,
 email VARCHAR ( 255 ) UNIQUE NOT NULL,
 created_on TIMESTAMP NOT NULL,
        last_login TIMESTAMP
);
CREATE TABLE

Check Table/Relations

To check your table:

postgres=# \dt
          List of relations
 Schema |   Name   | Type  |  Owner
--------+----------+-------+----------
 public | accounts | table | postgres
(1 row)

postgres=#

Use Docker Compose

Instead of raw docker command we can use docker compose to create and access to our PostgreSQL database.

Create a file named docker-compose.yml with below code:

version: '3.5'

volumes:
  local_postgres_data: {}

services:
  postgres:
    build: ./
    image: postgres:11.6
    container_name: localpostgres
    environment:
      POSTGRES_DB: ${POSTGRES_DB:-testdb}
      POSTGRES_USER: ${POSTGRES_USER:-debug}
      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD:-debug}
      POSTGRES_PORT: ${POSTGRES_PORT:-5432}
      POSTGRES_HOST: ${POSTGRES_HOST:-postgres}
    volumes:
      - local_postgres_data:/var/lib/postgresql/data
    ports:
      - "127.0.0.1:5432:5432"

Spin up our container:

$ docker-compose up -d

Creating localpostgres ... done

This command builds, (re)creates, starts, and attaches to containers for a service.

Now we can directly connect the database -testdb, with the user -debug:

$ docker exec it localpostgres psql -U debug -d testdb

psql (11.6 (Debian 11.6-1.pgdg90+1))
Type "help" for help.

testdb=#

All done!