p.haul-ssh

#!/bin/bash

set -e

# This script is a p.haul wrapper that allows to migrate process
# using ssh tunnel for transferring data and without having to
# start p.haul-service in advance. Script use p.haul-wrap helper script
# to establish required connections and specify these connections via
# command line arguments.
#
# This script performs folowing actions:
# 1) Launch p.haul-service on the remote and bind it to localhost:REM_PORT
# 2) Parse cmdline options to extract ssh* opts and change
#	 p.haul opts appropriately, so p.haul will connect to
#	 localhost:LOC_PORT, that will be followed to the remote
#	 through the ssh tunnel.
# 3) Establish ssh tunnel localhost:LOC_PORT->SSH->localhost:REM_PORT.
# 4) Launch p.haul to start migration.

TUNNEL_FLAGS="-o ExitOnForwardFailure=yes -fN "
SERVER_FLAGS="-ttfM "
LOC_PORT=54321
REM_PORT=12345
PORT=22
USER="$(whoami)"
REMOTE=""
LOG="/tmp/phs.log"

PH_EXEC="p.haul"
PH_WRAP_EXEC="p.haul-wrap"
PH_WRAP_OPTS=()

PHS_EXEC="p.haul-service"
PHS_WRAP_EXEC="p.haul-wrap"
PHS_WRAP_OPTS=()

usage=\
"SSH wrapper for p.haul\n\
Usage: p.haul-ssh [SSH_OPTIONS] [PHAUL_WRAP_OPTIONS]
\n\
SSH options:\n\
  --ssh-compression	  Use compression in ssh tunnel\n\
  --ssh-username	  Remote username (current user by default)\n\
  --ssh-loc-port	  Local port to use for forwarding (${LOC_PORT} by default)\n\
  --ssh-port		  SSH port (${PORT} by default)\n\
  --ssh-log			  Logfile for service log\n\
  --ssh-ph-exec		  Path to p.haul executable\n\
  --ssh-ph-wrap-exec  Path to p.haul-wrap executable\n\
  --ssh-phs-exec	  Path to p.haul-service executable on the remote machine\n\
  --ssh-phs-wrap-exec Path to p.haul-wrap executable on the remote machine\n\
  --help			  Print this messange\n\
\n\
See p.haul-wrap --help and p.haul --help for PHAUL_WRAP_OPTIONS\n"

while [ "$1" != "" ]; do
	case $1 in
	"--ssh-compression")
		SERVER_FLAGS="${SERVER_FLAGS} -C"
		TUNNEL_FLAGS="${TUNNEL_FLAGS} -C"
		;;
	"--ssh-username")
		shift
		USER=$1
		;;
	"--ssh-loc-port")
		shift
		LOC_PORT=$1
		;;
	"--port")
		# Extract --port option(if present).
		# --port LOC_PORT is added below.
		shift
		REM_PORT=$1
		;;
	"--ssh-ph-exec")
		shift
		PH_EXEC=$1
		;;
	"--ssh-ph-wrap-exec")
		shift
		PH_WRAP_EXEC=$1
		;;
	"--ssh-phs-exec")
		shift
		PHS_EXEC=$1
		;;
	"--ssh-phs-wrap-exec")
		shift
		PHS_WRAP_EXEC=$1
		;;
	"--ssh-port")
		shift
		PORT=$1
		;;
	"--ssh-log")
		shift
		LOG=$1
		;;
	"--help")
		printf "${usage}"
		exit 0
		;;
	*)
		PH_WRAP_OPTS+=($1)
		;;
	esac
	shift
done

# Replace p.haul positional "to" option with 127.0.0.1
REMOTE=${PH_WRAP_OPTS[0]}
PH_WRAP_OPTS[0]="127.0.0.1"

# Tell p.haul to connect to the local port
PH_WRAP_OPTS+=("--port ${LOC_PORT}")

# Specify path to p.haul executable
PH_WRAP_OPTS+=("--path ${PH_EXEC}")

# Tell p.haul-service to bind on localhost, so it is not directly accesible
# from the outer web.
PHS_OPTS+=("--bind-port ${REM_PORT}")
PHS_OPTS+=("--bind-addr \"127.0.0.1\"")

# Specify path to p.haul-service executable
PHS_WRAP_OPTS+=("--path ${PHS_EXEC}")

# Use ssh multiplexing to speedup establishing additional ssh sessions and
# to get control over all of them.
CTL_SK="~/ph_ssh_${USER}_${REMOTE}_${PORT}"
SSH_BASE="ssh -p ${PORT} ${USER}@${REMOTE} -S ${CTL_SK}"

# Trap EXIT to stop ssh connection(i.e. all ssh sessions) on both normal
# and error(see "set -e" above) exits.
trap '${SSH_BASE} -S ${CTL_SK} -O exit &> /dev/null' EXIT

echo "Start p.haul-service"
${SSH_BASE} ${SERVER_FLAGS} ${PHS_WRAP_EXEC} service ${PHS_WRAP_OPTS[@]} &> ${LOG} < /dev/null
echo "Done"

echo "Checking that p.haul-service is started"
${SSH_BASE} "while netstat -lnt | awk '\$4 ~ /:${REM_PORT}$/ {exit 1}'; do echo 'Waiting...'; sleep 1; done"

echo "Start ssh tunnel"
${SSH_BASE} ${TUNNEL_FLAGS} -L 127.0.0.1:${LOC_PORT}:127.0.0.1:${REM_PORT}
echo "Done"

echo "Launch p.haul"
${PH_WRAP_EXEC} client ${PH_WRAP_OPTS[@]}
echo "Done"