configure

#!/bin/sh

set -eu

DOCKER='docker'
DOCKER_GOLANG_IMG='golang:latest'
GO='go'
M4='m4'
USE_DOCKER='TEST'
USE_DOCKER_GO='TEST'

HELP_MSG="./configure [ OPTIONS ]

Available options:

	-h, --help
		Print this message.

	--with-m4=CMD
		Explicitly specify m4 command.
		Default: ${M4}

	--with-docker[=CMD]
		Explicitly specify use of Docker. Optionally specify base
		docker command to use (not including mount option, image name,
		or go command).
		Default: ${DOCKER} (if present)

	--without-docker
		Explicitly specify not to use Docker.
		Default: use if present

	--with-docker-golang[=IMG]
		Explicitly specify the use of Docker-based golang instead of
		the host golang binary (which will be used by default if it
		exists). Optionally specify the image name to use.
		Default: ${DOCKER_GOLANG_IMG} (if no local go binary)

	--with-go=CMD
		Explicitly specify golang command.
		Default: ${GO} (if present)
"

while [ $# -ne 0 ]; do
	case $1 in
	--with-m4=*)
		M4="`echo -n ${1} | sed 's/^--with-m4=\(.*\)$/\1/'`"
		;;
	--with-docker=*)
		DOCKER="`echo -n ${1} | sed 's/^--with-docker=\(.*\)$/\1/'`"
		USE_DOCKER='TRUE'
		;;
	--with-docker)
		USE_DOCKER='TRUE'
		;;
	--without-docker)
		USE_DOCKER='FALSE'
		;;
	--with-docker-golang=*)
		DOCKER_GOLANG_IMG="`echo -n ${1} \
			| sed 's/^--with-docker-golang=\(.*\)$/\1/'`"
		USE_DOCKER='TRUE'
		USE_DOCKER_GO='TRUE'
		;;
	--with-docker-golang)
		USE_DOCKER='TRUE'
		USE_DOCKER_GO='TRUE'
		;;
	--with-go=*)
		GO="`echo -n ${1} | sed 's/^--with-go=\(.*\)$/\1/'`"
		;;
	--help|-h)
		echo "${HELP_MSG}"
		exit 0
		;;
	*)
		echo "${HELP_MSG}" >&2
		exit 1
		;;
	esac
	shift
done

if [ "x${USE_DOCKER}" = 'xTEST' ]; then
	echo -n 'checking for docker... '
	if command -V docker; then
		USE_DOCKER='TRUE'
	else
		USE_DOCKER='FALSE'
	fi
fi

if [ "x${USE_DOCKER_GO}" = 'xTEST' ]; then
	echo -n 'checking for go... '
	if command -V go; then
		USE_DOCKER_GO='FALSE'
	else
		USE_DOCKER_GO='TRUE'
		echo 'no local go binary, dockerized golang required'
	fi
fi

if [ "x${USE_DOCKER_GO}" = 'xTRUE' ]; then
	if [ "x${USE_DOCKER}" = 'xFALSE' ]; then
		echo 'docker required for dockerized golang, aborting' >&2
		exit 1
	fi
fi

if [ "x${USE_DOCKER}" = 'xTRUE' ]; then
	USE_DOCKER_FLAG='-D _USE_DOCKER_'
else
	USE_DOCKER_FLAG='-U _USE_DOCKER_'
fi
if [ "x${USE_DOCKER_GO}" = 'xTRUE' ]; then
	USE_DOCKER_GO_FLAG='-D _USE_DOCKER_GO_'
else
	USE_DOCKER_GO_FLAG='-U _USE_DOCKER_GO_'
fi

echo -n "\nwriting out Makefile... "
${M4} \
	-D _GO_CMD_="${GO}" \
	-D _DOCKER_CMD_="${DOCKER}" \
	-D _DOCKER_GOLANG_IMG_="${DOCKER_GOLANG_IMG}" \
	${USE_DOCKER_FLAG} ${USE_DOCKER_GO_FLAG} \
	< Makefile.in > Makefile
echo 'done'