start-postgres-db.sh

#!/bin/bash 

# usage: file_env VAR [DEFAULT]
#    ie: file_env 'XYZ_DB_PASSWORD' 'example'
# (will allow for "$XYZ_DB_PASSWORD_FILE" to fill in the value of
#  "$XYZ_DB_PASSWORD" from a file, especially for Docker's secrets feature)
file_env() {
	local var="$1"
	local fileVar="${var}_FILE"
	local def="${2:-}"
	if [ "${!var:-}" ] && [ "${!fileVar:-}" ]; then
		echo >&2 "error: both $var and $fileVar are set (but are exclusive)"
		exit 1
	fi
	local val="$def"
	if [ "${!var:-}" ]; then
		val="${!var}"
	elif [ "${!fileVar:-}" ]; then
		val="$(< "${!fileVar}")"
	fi
	export "$var"="$val"
	unset "$fileVar"
}


mkdir -p "$PGDATA"
chown -R "$(id -u)" "$PGDATA" 2>/dev/null || :
chmod 700 "$PGDATA" 2>/dev/null || :

# look specifically for PG_VERSION, as it is expected in the DB dir
if [ ! -s "$PGDATA/PG_VERSION" ]; then
	file_env 'POSTGRES_INITDB_ARGS'
	if [ "$POSTGRES_INITDB_WALDIR" ]; then
		export POSTGRES_INITDB_ARGS="$POSTGRES_INITDB_ARGS --waldir $POSTGRES_INITDB_WALDIR"
	fi
	eval "initdb --username=postgres $POSTGRES_INITDB_ARGS"

	# check password first so we can output the warning before postgres
	# messes it up
	file_env 'POSTGRES_PASSWORD'
	if [ "$POSTGRES_PASSWORD" ]; then
		pass="PASSWORD '$POSTGRES_PASSWORD'"
		authMethod=md5
	else
		# The - option suppresses leading tabs but *not* spaces. :)
		cat >&2 <<-'EOWARN'
			****************************************************
			WARNING: No password has been set for the database.
			         This will allow anyone with access to the
			         Postgres port to access your database. In
			         Docker's default configuration, this is
			         effectively any other container on the same
			         system.

			         Use "-e POSTGRES_PASSWORD=password" to set
			         it in "docker run".
			****************************************************
		EOWARN

		pass=
		authMethod=trust
	fi

	{
		echo
		echo "host all all all $authMethod"
	} >> "$PGDATA/pg_hba.conf"

	# internal start of server in order to allow set-up using psql-client
	# does not listen on external TCP/IP and waits until start finishes
	PGUSER="${PGUSER:-postgres}" \
	pg_ctl -D "$PGDATA" \
		-o "-c listen_addresses='localhost'" \
		-w start

	file_env 'POSTGRES_USER' 'postgres'
	file_env 'POSTGRES_DB' "$POSTGRES_USER"

	psql=( psql -v ON_ERROR_STOP=1 )

	if [ "$POSTGRES_DB" != 'postgres' ]; then
		"${psql[@]}" --username postgres <<-EOSQL
			CREATE DATABASE "$POSTGRES_DB" ;
		EOSQL
		echo
	fi

	if [ "$POSTGRES_USER" = 'postgres' ]; then
		op='ALTER'
	else
		op='CREATE'
	fi
	"${psql[@]}" --username postgres <<-EOSQL
		$op USER "$POSTGRES_USER" WITH SUPERUSER $pass ;
	EOSQL
	echo

  echo "${psql[@]}" 
	psql+=( --username "$POSTGRES_USER" --dbname "$POSTGRES_DB" )

	echo
	for f in /scripts/prebuild/*; do
		case "$f" in
			*.sh)     echo "$0: running $f"; . "$f" ;;
			*.sql)    echo "$0: running $f"; "${psql[@]}" -f "$f"; echo ;;
			*.sql.gz) echo "$0: running $f"; gunzip -c "$f" | "${psql[@]}"; echo ;;
			*)        echo "$0: ignoring $f" ;;
		esac
		echo
	done

  # Do NOT shut down here as in the 'master branch.'
  # PGUSER="${PGUSER:-postgres}" \
  # pg_ctl -D "$PGDATA" -m fast -w stop

	echo
	echo 'PostgreSQL database is running and available for queries by root.'
	echo
fi