bash-com/launch

#!/bin/bash


# (1) Primary setup
#--------------------------------------------------------#
# (1) Get current ABS directory
ROOT=$(dirname `realpath $0`);

# (2) Check required arguments
test $# -lt 4 && echo -e "ERR: Missing arguments\n\nARGUMENTS:\n\tname\t\tThe name of the machine\n\ttarget_host\tThe hostname (or ip) of the target\n\tout_port\tThe port you want to use to send\n\tin_port\t\tThe port the peer uses to listen\n\ttrigger_port\tOptional param. Used to trigger the peer connection\n" && exit 1;

# (3) Manage optional param #
TRIGGER="";
test $# -ge 5 && TRIGGER="$5";


# (2) Secondary setup
#--------------------------------------------------------#
# (1) Create config dir (if doesn't exist) #
test ! -d $ROOT/config && mkdir $ROOT/config;

# (2) Reset configuration file (if exists)
CONF_FILE=$ROOT/config/$1;
test -f $CONF_FILE && rm $CONF_FILE;

# (3) Create buffer paths
BUF_IN="/tmp/buf_in_$1";
BUF_OUT="/tmp/buf_out_$1";

# (4) Flush buffers
echo -ne "" > $BUF_IN;
echo -ne "" > $BUF_OUT;


# (3) Launch INPUT server
#--------------------------------------------------------#
# (1) Start the script in background
(

	trap "echo 'launch.server.killed'; kill -9 %1 2>/dev/null && echo 'launch.server.nc.killed';" INT KILL;

	infail=0;

	# kill script after 10 failures
	while [ $infail -lt 10 ]; do

		# main command
		echo "(.) started [input]";
		( nc -lp $4 >> $BUF_IN 2> /dev/null && infail=0 || ( infail=`expr $infail + 1`; exit 1 ) || echo "Port $4 already in use" ) &
		wait $!;

		# try to kill proccess that uses port if failed and such proccess exists
		if [ $infail -eq 0 ]; then
			echo "    > END [input]";
		else
			echo "    > FAIL [input]";
			LISTEN_PID=`lsof -n -i4TCP:$4 | grep LISTEN | awk '{print $2}'`;
			test ! -z "$LISTEN_PID" && kill -9 $LISTEN_PID 2>/dev/null;
		fi;

	done;

)&

# (2) Store the background proccess PID #
IN_PID=$!;





################################
# IF SET, SEND TRIGGER TO PEER #
################################
test ! -z "$TRIGGER" && ( echo "(.) sending [trigger:$2:$TRIGGER]"; bash -c "exec 3<>/dev/tcp/$2/$TRIGGER" && echo "    > SENT [trigger:$2:$TRIGGER]" || echo "    > ERR [trigger:$2:$TRIGGER]" )

##################################
# WAIT 2s FOR THE PEER TO LISTEN #
##################################
sleep 2;





# (4) Launch OUTPUT client
#--------------------------------------------------------#
# (1) Start the script in background
(

	trap "echo 'launch.client.killed'; kill -9 %1 2>/dev/null && echo 'launch.client.nc.killed';" INT KILL;

	outfail=0;

	# stop after 5 failed attempts
	while [ $outfail -lt 5 ]; do

		# main command
		echo "(.) started [output]";
		( tail -f $BUF_OUT | nc $2 $3 2>/dev/null && outfail=0 || ( outfail=`expr $outfail + 1`; exit 1 ) || echo "Cannot connect to $2:$3"  ) &
		wait $!;

		test $outfail -eq 0 && echo "    > END [output]" || echo "    > FAIL [output]";

		sleep 1; # can sleep because the buffer is never flushed

	done;

)&

# (2) Store the background proccess PID #
OUT_PID=$!;



# (5) Store the config file for 'write' + 'send' to work properly
#--------------------------------------------------------#
# (1) Store config file in 'config/$NAME'
echo -e "#!/bin/bash\nBUF_IN=\"$BUF_IN\"; BUF_OUT=\"$BUF_OUT\";\nIN_PID=$IN_PID; OUT_PID=$OUT_PID;\n" > $CONF_FILE;

# (2) Notify server started #



# (6) Manage ending proccess
#--------------------------------------------------------#
# (1) Kill subproccesses if Ctrl+C #
on_exit(){
	echo "launch.kill";

	## {1} Kill client ##
	echo 'launch.client.kill';
	kill -9 $OUT_PID 2>/dev/null;

	## {2} Kill server ##
	echo 'launch.server.kill';
	kill -9 $IN_PID  2>/dev/null;

	## {3} Remove config file ##
	echo 'launch.config.delete';
	rm $CONF_FILE  2>/dev/null;

	## {4} Remove buffers ##
	echo 'launch.buffer.in.delete';
	echo 'launch.buffer.out.delete';
	rm $BUF_OUT $BUF_IN 2>/dev/null;

	exit 0;
}

# (2) Setup trap for signals INT + KILL #
trap "on_exit" INT KILL;

# (2) Wait for daemons to stop #
wait $OUT_PID;
wait $IN_PID;

on_exit;