bash-com/master

#!/bin/bash


# (1) Init.
#--------------------------------------------------------#
# (1) Get current absolute dir
ROOT=$(dirname `realpath $0`);

# (2) Check argc
test $# -lt 2 && echo -e "error: too few arguments\n\n\e[1mUSAGE\e[0m\n\tmaster <key> <host> <port> <dir>\n\n\e[1mARGUMENTS\e[0m\n\t<key>\tThe key of the pool\n\t<host>\tThe host where the pool is hosted\n\t<port>\tTo port where the pool is bound\n\t<dir>\tThe folder containing ONLY the logger daemons\n" && exit 1;

# (3) Check @PORT range #
MIN_PORT=1024;
MAX_PORT=49151;
test "$3" -gt "$MAX_PORT" -o "$3" -lt "$MIN_PORT" && echo "error: <port> must be between $MIN_PORT and $MAX_PORT" && exit 1;

# (4) Set argument explicit names #
POOL_KEY="$1";
POOL_HOST="$2";
POOL_PORT="$3";
LOGGER_DIR="`realpath $4`";

# (5) Check @LOGGER_DIR #
test ! -d "$LOGGER_DIR" && echo "error: <dir> is not a valid folder." && exit 1;

# (6) init logger variables #
declare -A OUTPUT_PID; # will contain each bind-output PIDs
declare -A LOGGER_PID; # will contain each logger PIDs

# (7) get logger list #
LOGGERS=(`ls $LOGGER_DIR`);

# (8) If no logger -> exit #
test "${#LOGGERS[@]}" -eq 0 && echo "error: no logger found in <dir>." && exit 1;

# (9) Get local IP address #
LOCAL_IP="`ip addr | grep 'state UP' -A2 | tail -n1 | awk '{print $2}' | cut -f1  -d'/'`";

test -z "$LOCAL_IP" && echo "error: cannot get local IP address." && exit 1;

# (10) Create a temporary file #
TMPFILE="/dev/shm/master_pid";



# (2) Set exit management
#--------------------------------------------------------#
# (1) On-Exit routine #
on_exit(){

	echo "- killing ${#OUTPUT_PID[@]} output";
	for logger_name in "${!OUTPUT_PID[@]}"; do

		# kill each logger OUTPUT
		echo "  - killing $logger_name (${OUTPUT_PID[$logger_name]})";
		kill -INT ${OUTPUT_PID[$logger_name]} 2>/dev/null;

	done;

	echo "- killing ${#LOGGER_PID[@]} loggers";
	for logger_name in "${!LOGGER_PID[@]}"; do

		# kill each logger OUTPUT
		echo "  - killing $logger_name (${LOGGER_PID[$logger_name]})";
		kill -INT ${LOGGER_PID[$logger_name]} 2>/dev/null;

	done;

	echo "- killing main output";
	kill -INT $MASTER_PID 2>/dev/null;

	echo "- killing loop";
	# kill -INT $LOOP_PID 2>/dev/null;

	# delete tmp file
	echo "- deleting tmp file";
	rm $TMPFILE 2>/dev/null;

}

trap "on_exit;" HUP INT KILL TERM;





# (3) Connect to pool
#--------------------------------------------------------#
# (1) Bind-output #
echo -e "\e[32m+\e[0m connect to $POOL_HOST:$POOL_PORT";
$ROOT/bind-output master $POOL_HOST $POOL_PORT > $TMPFILE;
MASTER_PID="`cat $TMPFILE`";

echo "  + flush connection before using it";
# $ROOT/write master "";

# (4) Launch master manager
#--------------------------------------------------------#
# (1) For each logger
for logger_name in "${LOGGERS[@]}"; do

	echo "  + logger '$logger_name'";

	# Find an available port
	PORT="$MIN_PORT";
	while true; do

		# if port not in use -> use it
		ss -tl4 "( sport = :$PORT )" | grep "$PORT" >/dev/null 2>&1 || break;

		# else try next port (+1)
		PORT="`expr $PORT + 1`";

	done;

	# listen for pool response (port number)
	echo -e "    \e[32m+\e[0m listen $PORT";
	$ROOT/bind-input freeport $PORT > $TMPFILE;
	FREEPORT_PID="`cat $TMPFILE`";

	sleep 1;

	# send port request
	echo "    + sending port request";
	$ROOT/write master "$POOL_KEY:$logger_name:$LOCAL_IP:$PORT";

	echo "      + waiting for response";
	RESP="";
	timeout=8; # 4sec = 8 x .5sec
	while [ "$timeout" -gt "0" ]; do

		RESP="`$ROOT/read freeport`";

		# if empty answer, try again in .5 sec
		if [ -z "$RESP" ]; then
			# echo "        + empty response (remaining $timeout)";
			timeout="`expr $timeout - 1`";
			sleep .5;
			continue;

		# else -> stop reading
		else
			# echo "        + got response '$RESP'";
			break;
		fi

	done;

	# closing listen socket
	echo -e "      + received '\e[33m$RESP\e[0m'";
	echo -e "    \e[31m+\e[0m stop listening on $PORT";
	kill -INT $FREEPORT_PID 2>/dev/null;

	# empty response -> ignore
	test -z "$RESP" && echo "      + no answer" && continue;

	# not a number -> ignore
	echo -n "$RESP" | grep -P '^\d+$' >/dev/null || ( echo "      + invalid format"; exit 1 ) || continue;

	# Create output bound
	echo "    + connecting to $POOL_HOST:$RESP";
	$ROOT/bind-output $logger_name $POOL_HOST $RESP > $TMPFILE;
	OUTPUT_PID[$logger_name]="`cat $TMPFILE`";

	echo "    + logger launched in background";
	# launch logger bound to output
	( $LOGGER_DIR/$logger_name | cat > /tmp/outbuf_$logger_name )&
	LOGGER_PID[$logger_name]=$!;

done;


# When all loggers are bound, destroy pool connection

# 1. Send END msg to pool (but wait for it to manage last logger)
sleep 2;
$ROOT/write master "END${POOL_KEY}END";

# 2. Close pool connection
echo -e "\e[31m+\e[0m close connection to $POOL_HOST:$POOL_PORT ";
kill -INT $MASTER_PID 2>/dev/null;

echo "  + ${#LOGGER_PID[@]} loggers running in background";
for logger_name in "${!LOGGER_PID[@]}"; do

	wait ${LOGGER_PID[$logger_name]};

done;

on_exit;