add check for stale PID file or old processes to gracefully handle hard container stop/starts, discussed in #144

config/root/etc/services.d/gunicorn/run

@@ -5,5 +5,20 @@ umask "$UMASK_SET"
 
 cd /app || exit
 
+PIDFILE=/run/app/gunicorn.pid
+
+if [ -f "${PIDFILE}" ]
+then
+    PID=$(cat $PIDFILE)
+    echo "Unexpected PID file exists at ${PIDFILE} with PID: ${PID}"
+    if kill -0 $PID
+    then
+        echo "Killing old gunicorn process with PID: ${PID}"
+        kill -9 $PID
+    fi
+    echo "Removing stale PID file: ${PIDFILE}"
+    rm ${PIDFILE}
+fi
+
 exec s6-setuidgid app \
     /usr/local/bin/gunicorn -c /app/tubesync/gunicorn.py --capture-output tubesync.wsgi:application