docker-entrypoint.sh

#!/bin/bash
set -e

# 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"
}

if [ "${1:0:1}" = '-' ]; then
	set -- postgres "$@"
fi

if [ "$1" = 'postgres' ]; then

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

	    # Uncomment the listen_addresses setting
	    sed -ri "s/^#(listen_addresses\s*=\s*)\S+/\1'*'/" "$PGDATA"/postgresql.conf
		sed -ri "s/^#(listen_addresses\s*=\s*)\S+/\1'*'/" "$PGDATA"/postgresql.conf

	    # Add pg_stats_statements to the config for
	    sed -ri "s/^#(shared_preload_libraries = )''.*/\1 'pg_cron,pg_stat_statements'/" "$PGDATA"/postgresql.conf
	    { echo; echo "pg_stat_statements.max = 10000"; } | tee -a "$PGDATA"/postgresql.conf > /dev/null
	    { echo; echo "pg_stat_statements.track = all"; } | tee -a "$PGDATA"/postgresql.conf > /dev/null
	    { echo; echo "cron.database_name = 'postgres'"; } | tee -a "$PGDATA"/postgresql.conf > /dev/null

		# 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 $authMethod"; } | tee -a "$PGDATA/pg_hba.conf" > /dev/null

		# 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
		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

		psql+=( --username "$POSTGRES_USER" --dbname "$POSTGRES_DB" )

		echo
		for f in /docker-entrypoint-initdb.d/*; 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 ;;
				*.conf)   echo "$0: including custom conf $f"; echo "include '$f'" | tee -a "$PGDATA"/postgresql.conf > /dev/null; echo ;;
				*)        echo "$0: ignoring $f" ;;
			esac
			echo
		done

		pg_ctl -D "$PGDATA" -m fast -w stop

		echo
		echo 'PostgreSQL init process complete; ready for start up.'
		echo
	fi

	exec "$@"
fi

exec "$@"