Multiple Docker PostgreSQL databases

.env

POSTGRES_USER=db_name_1
POSTGRES_DB=db_name_1
POSTGRES_PASSWORD=pass123
POSTGRES_MULTIPLE_DATABASES=db_name_1,db_name_2
POSTGRES_PASSWORDS=pass123,pass12345

readme.md

1. Create dir contrib/db/docker-entrypoint-initdb.d
2. Place create-multiple-postgresql-databases.sh in docker-entrypoint-initdb.d.

create-multiple-postgresql-databases.sh

#!/bin/bash

set -e
set -u

function create_user_and_database() {
	local database=$1
    local password=$2
	echo "  Creating user and database '$database'"
	psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" <<-EOSQL
	    CREATE USER $database WITH PASSWORD '$password';
	    CREATE DATABASE $database;
	    GRANT ALL PRIVILEGES ON DATABASE $database TO $database;
EOSQL
}

if [ -n "$POSTGRES_MULTIPLE_DATABASES" ] && [ -n "$POSTGRES_PASSWORDS" ]; then
	echo "Multiple database creation requested: $POSTGRES_MULTIPLE_DATABASES"
	IFS=',' read -ra DBS <<< "$POSTGRES_MULTIPLE_DATABASES"
	IFS=',' read -ra PASSWORDS <<< "$POSTGRES_PASSWORDS"
	for i in "${!DBS[@]}"; do
		db=${DBS[$i]}
		password=${PASSWORDS[$i]}
		create_user_and_database $db $password
	done
	echo "Multiple databases created"
fi

docker-compose.yml

version: "3.8"

services:

  db:
    image: postgres:14
    restart: unless-stopped
    env_file:
      .env
    ports:
      - "5432:5432"
    volumes:
      - ./contrib/db/docker-entrypoint-initdb.d:/docker-entrypoint-initdb.d:ro
      - db:/var/lib/postgresql/data

volumes:
  db: