Use label explicitly for identifing container.

Author: usualoma

mt/common.yml

@@ -17,6 +17,8 @@ services:
       - "support:/var/www/cgi-bin/mt/mt-static/support"
       # override entrypoint
       - "./docker-entrypoint.sh:/usr/local/bin/docker-entrypoint.sh"
+    labels:
+      mt-dev.service: "mt"
 
   httpd:
     image: ${DOCKER_HTTPD_IMAGE:-movabletype/test:php-7.3}

mt/mt-watcher.pl

@@ -31,7 +31,8 @@
             return unless @paths;
 
             print( join( "\n", @paths ) . "\n" );
-            system('docker kill -s HUP mt_mt_1');
+            my $mt_container_id = `docker ps -q --filter label=mt-dev.service=mt`;
+            system("docker kill -s HUP $mt_container_id");
 
             # throttling
             sleep(1);