diff --git a/gs_cache/.vpython b/gs_cache/.vpython
index 2855ba9..d6f8482 100644
--- a/gs_cache/.vpython
+++ b/gs_cache/.vpython
@@ -61,6 +61,16 @@
 >
 
 wheel: <
+  name: "infra/python/wheels/pyasn1-py2_py3"
+  version: "version:0.2.3"
+>
+
+wheel: <
+  name: "infra/python/wheels/pyasn1_modules-py2_py3"
+  version: "version:0.0.8"
+>
+
+wheel: <
   name: "infra/python/wheels/pytest-py2_py3"
   version: "version:3.5.0"
 >
@@ -81,6 +91,11 @@
 >
 
 wheel: <
+  name: "infra/python/wheels/rsa-py2_py3"
+  version: "version:3.4.2"
+>
+
+wheel: <
   name: "infra/python/wheels/six-py2_py3"
   version: "version:1.11.0"
 >
diff --git a/gs_cache/nginx_access_log_metrics.py b/gs_cache/nginx_access_log_metrics.py
index 8ec0ce8..098f851 100644
--- a/gs_cache/nginx_access_log_metrics.py
+++ b/gs_cache/nginx_access_log_metrics.py
@@ -110,8 +110,8 @@
             "(use '-' to indicate reading from sys.stdin).")
   )
   parser.add_argument(
-      "-l", "--log-file", required=True,
-      help="Log file of this script."
+      "-l", "--log-file", default=sys.stdout,
+      help="Log file of this script (default is sys.stdout)."
   )
   return parser.parse_args(argv)
 
@@ -121,10 +121,13 @@
   args = parse_args(argv)
 
   logger = logging.getLogger()
-  logger.addHandler(handlers.TimedRotatingFileHandler(
-      args.log_file, when=_LOG_ROTATION_TIME,
-      interval=_LOG_ROTATION_INTERVAL,
-      backupCount=_LOG_ROTATION_BACKUP))
+  if args.log_file is sys.stdout:
+    logger.addHandler(logging.StreamHandler(stream=sys.stdout))
+  else:
+    logger.addHandler(handlers.TimedRotatingFileHandler(
+        args.log_file, when=_LOG_ROTATION_TIME,
+        interval=_LOG_ROTATION_INTERVAL,
+        backupCount=_LOG_ROTATION_BACKUP))
   logger.setLevel(logging.DEBUG)
 
   with ts_mon_config.SetupTsMonGlobalState('gs_cache_nginx_log_metrics',