#!/usr/bin/env bash

 #
 # This script installs the bundle to Docker Machine instances, for the purpose
 # of testing the latest Docker with Swarm mode enabled.
 # Do not use in production.
 #
 # Requirements (on host to run this script)
 #  - bash is installed
 #  - Docker Machine is installed
 #  - GNU tar is installed
 #
 # Requirements (on Docker machine instances)
 #  - Docker can be managed via one of  `systemctl`, `service`, or `/etc/init.d/docker`
 #
 set -e
 set -o pipefail
 
 errexit() {
     echo "$1"
     exit 1
 }
 
 BUNDLE="bundles/$(cat VERSION)"
 
 bundle_files(){
     # prefer dynbinary if exists
     for f in dockerd docker-proxy; do
 	if [ -d $BUNDLE/dynbinary-daemon ]; then
 	    echo $BUNDLE/dynbinary-daemon/$f
 	else
 	    echo $BUNDLE/binary-daemon/$f
 	fi
     done

     for f in containerd ctr containerd-shim docker-init runc; do

 	echo $BUNDLE/binary-daemon/$f
     done
     if [ -d $BUNDLE/dynbinary-client ]; then
 	echo $BUNDLE/dynbinary-client/docker
     else
 	echo $BUNDLE/binary-client/docker
     fi
 }
 
 control_docker(){
     m=$1; op=$2
     # NOTE: `docker-machine ssh $m sh -c "foo bar"` does not work
     #       (but `docker-machine ssh $m sh -c "foo\ bar"` works)
     #       Anyway we avoid using `sh -c` here for avoiding confusion
     cat <<EOF | docker-machine ssh $m sudo sh
 if command -v systemctl > /dev/null; then
   systemctl $op docker
 elif command -v service > /dev/null; then
   service docker $op
 elif [ -x /etc/init.d/docker ]; then
   /etc/init.d/docker $op
 else
   echo "not sure how to control the docker daemon"
   exit 1
 fi
 EOF
 }
 
 detect_prefix(){
     m=$1
     script='dirname $(dirname $(which dockerd))'
     echo $script | docker-machine ssh $m sh
 }
 
 install_to(){
     m=$1; shift; files=$@
     echo "$m: detecting docker"
     prefix=$(detect_prefix $m)
     echo "$m: detected docker on $prefix"
     echo "$m: stopping docker"
     control_docker $m stop
     echo "$m: installing docker"
     # NOTE: GNU tar is required because we use --transform here
     # TODO: compression (should not be default)
     tar ch --transform 's/.*\///' $files | docker-machine ssh $m sudo tar Cx $prefix/bin
     echo "$m: starting docker"
     control_docker $m start
     echo "$m: done"
 }
 
 check_prereq(){
     command -v docker-machine > /dev/null || errexit "docker-machine not installed"
     ( tar --version | grep GNU > /dev/null ) || errexit "GNU tar not installed"
 }
 
 case "$1" in
     "install")
 	shift; machines=$@
 	check_prereq
 	files=$(bundle_files)
 	echo "Files to be installed:"
 	for f in $files; do echo $f; done
 	pids=()
 	for m in $machines; do
 	    install_to $m $files &
 	    pids+=($!)
 	done
 	status=0
 	for pid in ${pids[@]}; do
 	    wait $pid || { status=$?; echo "background process $pid failed with exit status $status"; }
 	done
 	exit $status
 	;;
     *)
 	errexit "Usage: $0 install MACHINES"
 	;;
 esac