From 84989a48f20d1bc383a9925b919edc66fc4bccdb Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Thu, 7 Jul 2016 01:06:45 +0000
Subject: update init and add systemd examples

Reduce raciness in the init script and add LSB tags.
However, the systemd examples should be race-free and
safer (if one feels safe using systemd :P)
---
 examples/init.sh | 43 ++++++++++++++++++++++++++++++++++---------
 1 file changed, 34 insertions(+), 9 deletions(-)

(limited to 'examples/init.sh')

diff --git a/examples/init.sh b/examples/init.sh
index 9464220..6fe1ae6 100644
--- a/examples/init.sh
+++ b/examples/init.sh
@@ -2,8 +2,14 @@
 # To the extent possible under law, Eric Wong has waived all copyright and
 # related or neighboring rights to this examples
 set -e
-# Example init script, this can be used with nginx, too,
-# since nginx and yahns accept the same signals
+### BEGIN INIT INFO
+# Provides:          yahns
+# Required-Start:    $local_fs $network
+# Required-Stop:     $local_fs $network
+# Default-Start:     2 3 4 5
+# Default-Stop:      0 1 6
+# Short-Description: Start/stop yahns Ruby app server
+### END INIT INFO
 
 # Feel free to change any of the following variables for your app:
 TIMEOUT=${TIMEOUT-60}
@@ -11,21 +17,22 @@ APP_ROOT=/home/x/my_app/current
 PID=$APP_ROOT/tmp/pids/yahns.pid
 CMD="/usr/bin/yahns -D -c $APP_ROOT/config/yahns.rb"
 INIT_CONF=$APP_ROOT/config/init.conf
+UPGRADE_DELAY=${UPGRADE_DELAY-2}
 action="$1"
 set -u
 
 test -f "$INIT_CONF" && . $INIT_CONF
 
-old_pid="$PID.oldbin"
+OLD="$PID.oldbin"
 
 cd $APP_ROOT || exit 1
 
 sig () {
-	test -s "$PID" && kill -$1 `cat $PID`
+	test -s "$PID" && kill -$1 $(cat $PID)
 }
 
 oldsig () {
-	test -s $old_pid && kill -$1 `cat $old_pid`
+	test -s "$OLD" && kill -$1 $(cat $OLD)
 }
 
 case $action in
@@ -47,18 +54,36 @@ restart|reload)
 	$CMD
 	;;
 upgrade)
-	if sig USR2 && sleep 2 && sig 0 && oldsig QUIT
+	if oldsig 0
+	then
+		echo >&2 "Old upgraded process still running with $OLD"
+		exit 1
+	fi
+
+	cur_pid=
+	if test -s "$PID"
+	then
+		cur_pid=$(cat $PID)
+	fi
+
+	if test -n "$cur_pid" &&
+			kill -USR2 "$cur_pid" &&
+			sleep $UPGRADE_DELAY &&
+			new_pid=$(cat $PID) &&
+			test x"$new_pid" != x"$cur_pid" &&
+			kill -0 "$new_pid" &&
+			kill -QUIT "$cur_pid"
 	then
 		n=$TIMEOUT
-		while test -s $old_pid && test $n -ge 0
+		while kill -0 "$cur_pid" 2>/dev/null && test $n -ge 0
 		do
 			printf '.' && sleep 1 && n=$(( $n - 1 ))
 		done
 		echo
 
-		if test $n -lt 0 && test -s $old_pid
+		if test $n -lt 0 && kill -0 "$cur_pid" 2>/dev/null
 		then
-			echo >&2 "$old_pid still exists after $TIMEOUT seconds"
+			echo >&2 "$cur_pid still running after $TIMEOUT seconds"
 			exit 1
 		fi
 		exit 0
-- 
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