Merge remote-tracking branch 'origin/jr/init'

* origin/jr/init:
  examples/init.sh: update to reduce upgrade raciness

examples/init.sh

@@ -1,29 +1,39 @@
 #!/bin/sh
 set -e
+### BEGIN INIT INFO
+# Provides:          unicorn
+# 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 unicorn Rack app server
+### END INIT INFO
+
 # Example init script, this can be used with nginx, too,
-# since nginx and unicorn accept the same signals
+# since nginx and unicorn accept the same signals.
 
 # Feel free to change any of the following variables for your app:
 TIMEOUT=${TIMEOUT-60}
 APP_ROOT=/home/x/my_app/current
 PID=$APP_ROOT/tmp/pids/unicorn.pid
 CMD="/usr/bin/unicorn -D -c $APP_ROOT/config/unicorn.rb"
 INIT_CONF=$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
@@ -45,18 +55,36 @@ 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