Crash when one of the multiple databases is the same as the user

[Hugo Duroux]

Snippet of my config :

    postgres:
        image: postgres:10-alpine
        container_name: postgres
        ports:
            - 5432:5432
        volumes:
            - "./.data/postgresql:/var/lib/postgresql/data"
            - ./utils/postgres:/docker-entrypoint-initdb.d
        environment:
            POSTGRES_MULTIPLE_DATABASES: "service_database, service_database_test"
            POSTGRES_PASSWORD: "password"
            POSTGRES_USER: "service_database"

In this case, the postgres image will create a database named "service_database" by default, then the multi db script will try to create "service_database" and "service_database_test" but will fail on "service_database" because the database already exists.

The workaround is easy: remove "service_database" from POSTGRES_MULTIPLE_DATABASES and eventually using POSTGRES_DB but it seems hacky to have to use multiple variables.

[Mart Sõmermaa]

Thanks for reporting this!

Let it simmer a bit as a reasonable workaround exists - adding logic for checking if DB name matches user name can be added to the script, but I think we can postpone the effort a bit until more people vote for this.

[Mart Sõmermaa]

I think this is actually another documentation issue like #5 - would you like to provide a README update like #7 for "fixing" #5 ?

[Marc Jovaní González]

This script works fine for me @Amoki. <3

#!/bin/bash

set -e
set -u

function user_exists() {
		local user=$1

		result=$(psql -U "$POSTGRES_USER" -tAc "SELECT 1 FROM pg_roles WHERE rolname = '${user}'" 'postgres')

		if [ -z "$result" ]; then
				return 1
		else
				return 0
		fi
}

function database_exists() {
		local database=$1

		result=$(psql -U "$POSTGRES_USER" -tAc "SELECT 1 FROM pg_database WHERE datname = '${database}'" postgres)

		if [ -z "$result" ]; then
				return 1
		else
				return 0
		fi
}

function create_user_and_database() {
		local database=$1

		echo ""
		echo "Creating '$database' database"
		echo ""

		if user_exists "$database"; then
				echo "Role '$database' already exists. Skipping..."
		else
				echo "Role '${database}' does not exist"

				psql -v ON_ERROR_STOP=1 -U "$POSTGRES_USER" <<-EOSQL
					CREATE USER $database WITH PASSWORD '$POSTGRES_PASSWORD';
				EOSQL
		fi

		if database_exists "$database"; then
				echo "Database '$database' already exists. Skipping..."
		else
				echo "Database '${database}' does not exist"

				psql -v ON_ERROR_STOP=1 -U "$POSTGRES_USER" <<-EOSQL
						CREATE DATABASE $database;
				EOSQL
		fi

		psql -v ON_ERROR_STOP=1 -U "$POSTGRES_USER" <<-EOSQL
			GRANT SET ON PARAMETER session_replication_role TO $database;
			ALTER DATABASE $database OWNER TO $database;
		EOSQL

		echo "Successful database creation '$database'"
		echo ""
}

if [ -n "$POSTGRES_MULTIPLE_DATABASES" ]; then
	echo "Multiple database creation requested: $POSTGRES_MULTIPLE_DATABASES"
	for db in $(echo $POSTGRES_MULTIPLE_DATABASES | tr ',' ' '); do
		create_user_and_database $db
	done
	echo "Multiple databases created"
fi

[Girish Bhutiya]

@drackp2m script works fine at my end but original script give me error.