Disable logging output from cherrypy and websocket by default

In this way, they do not mess up the screen for user prompts.

BUG=chromium:478631
TEST=Run touch_firmware_test and observe that there are no logs
from cherrypy/websocket.

Change-Id: Id574e5c7233bf259f56d22656051313cb78e6151
Reviewed-on: https://chromium-review.googlesource.com/266454
Reviewed-by: Charlie Mooney <charliemooney@chromium.org>
Commit-Queue: Shyh-In Hwang <josephsih@chromium.org>
Tested-by: Shyh-In Hwang <josephsih@chromium.org>
diff --git a/webplot/webplot.py b/webplot/webplot.py
index 52e21f1..79fa339 100755
--- a/webplot/webplot.py
+++ b/webplot/webplot.py
@@ -288,7 +288,8 @@
     webplot.GetAndPlotSnapshots()
   """
 
-  def __init__(self, server_addr, server_port, device, saved_file=SAVED_FILE):
+  def __init__(self, server_addr, server_port, device, saved_file=SAVED_FILE,
+               logging=False):
     self._server_addr = server_addr
     self._server_port = server_port
     self._device = device
@@ -298,6 +299,11 @@
     self.daemon = True
     self._prev_tids = []
 
+    # The logging is turned off by default when imported as a module so that
+    # it does not mess up the screen.
+    if not logging:
+      cherrypy.log.screen = None
+
     # Allow input traffic in iptables.
     EnableDestinationPort(self._server_port)
 
@@ -504,7 +510,7 @@
   """The main function to launch webplot service."""
   _CheckLegalUser()
 
-  configure_logger(level=logging.DEBUG)
+  configure_logger(level=logging.ERROR)
   args = _ParseArguments()
 
   print '\n' + '-' * 70
@@ -546,7 +552,7 @@
 
 
   # Instantiate a webplot server daemon and start it.
-  webplot = Webplot(args.server_addr, args.server_port, device)
+  webplot = Webplot(args.server_addr, args.server_port, device, logging=True)
   webplot.start()
 
   # Get touch snapshots from the touch device and have clients plot them.