web_server: Suppress warnings that static directories don't exist

When JSXC is not installed, currently we get warnings that jsxc directories are
not found when we start the web server.

Suppress warning that some of the static directories don't exist. Since there is
no way to add/remove those tree mounts at will, we need to add them all before
hand even if they don't exist now. If the directories becomes available later,
CherryPy serves them just fine.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: Veiko Aasa <veiko17@disroot.org>

plinth/web_server.py

@@ -5,6 +5,7 @@ Setup CherryPy web server.
 
 import logging
 import os
+import warnings
 
 import cherrypy
 
@@ -73,7 +74,16 @@ def init():
 
 def run(on_web_server_stop):
     """Start the web server and block it until exit."""
-    cherrypy.engine.start()
+    with warnings.catch_warnings():
+        # Suppress warning that some of the static directories don't exist.
+        # Since there is no way to add/remove those tree mounts at will, we
+        # need to add them all before hand even if they don't exist now. If the
+        # directories becomes available later, CherryPy serves them just fine.
+        warnings.filterwarnings(
+            'ignore', '(.|\n)*is not an existing filesystem path(.|\n)*',
+            UserWarning)
+        cherrypy.engine.start()
+
     cherrypy.engine.subscribe('stop', on_web_server_stop)
     cherrypy.engine.block()