Constrained Network test does not fail fast under fatal conditions.

media/tools/constrained_network_server/cns.py

Index: media/tools/constrained_network_server/cns.py
diff --git a/media/tools/constrained_network_server/cns.py b/media/tools/constrained_network_server/cns.py
index 4f0198d922d47c8a243465b31053abcea44fed71..db66c5ad253b3a8838cbf69e0fac2eccbbb25a77 100755
--- a/media/tools/constrained_network_server/cns.py
+++ b/media/tools/constrained_network_server/cns.py
@@ -12,6 +12,7 @@ TODO(dalecurtis): Add some more docs here.
 
 """
 
+import logging
 import mimetypes
 import optparse
 import os
@@ -31,6 +32,9 @@ except ImportError:
 # Add webm file types to mimetypes map since cherrypy's default type is text.
 mimetypes.types_map['.webm'] = 'video/webm'
 
+# Default logging is ERROR. Use --verbose to enable DEBUG logging.
+_DEFAULT_LOG_LEVEL = logging.ERROR
+
 # Default port to serve the CNS on.
 _DEFAULT_SERVING_PORT = 9000
 
@@ -287,6 +291,8 @@ def ParseArgs():
   parser.add_option('--www-root', default=os.getcwd(),
                     help=('Directory root to serve files from. Defaults to the '
                           'current directory: %default'))
+  parser.add_option('-v', '--verbose', action='store_true', dest='verbose',
+                    default=False, help='Turn on verbose output.')
 
   options = parser.parse_args()[0]
 
@@ -300,12 +306,32 @@ def ParseArgs():
   # Convert the path to an absolute to remove any . or ..
   options.www_root = os.path.abspath(options.www_root)
 
+  # Required so that cherrypy logs do not get propagated to root logger causing
+  # the logs to be printed twice.
+  cherrypy.log.error_log.propagate = False
+
+  _SetLogger(options.verbose)
+
   return options
 
 
+def _SetLogger(verbose):
+  # Logging is used for traffic_control debug statements.
+  log_level = _DEFAULT_LOG_LEVEL
+  if verbose:
+    log_level = logging.DEBUG
+  logging.basicConfig(level=log_level, format='%(message)s')

[DaleCurtis, 2012/01/06 23:19:42]

Need a more descriptive message here. One that is more similar to cherrypy.log.
Since multiple requests will be coming in at once, it will be impossible to
differentiate them w/o more detail.

[shadi, 2012/01/07 04:56:19]

cherrypy.log only shows date. I added thread number to the format, the date is
printed automatically.
On 2012/01/06 23:19:42, DaleCurtis wrote:

[DaleCurtis, 2012/01/09 19:21:19]

Ah, I'm thinking of cherrypy.request.log() I think. The logs I've seen show the
request IP and some other information in addition to the timestamp.

We should probably be using that instead to make sure logs can be read easily.

+
+
+def _CheckRootAccess():

[DaleCurtis, 2012/01/06 23:19:42]

This is not complete and should instead be in the traffic_control library.

Something like: CheckRequirements() throws an exception if a requirement is
missing.

By not complete I mean you need to check if 'sudo -n [tc|iptables]' passes w/o
input (as mentioned in the ticket).

[shadi, 2012/01/07 04:56:19]

Check http://codereview.chromium.org/9125022/
On 2012/01/06 23:19:42, DaleCurtis wrote:

+  if os.geteuid() != 0:
+    sys.exit('Need root access to run a constrained server.')
+
+
 def Main():
   """Configure and start the ConstrainedNetworkServer."""
   options = ParseArgs()
+  _CheckRootAccess()
 
   cherrypy.config.update(
       {'server.socket_host': '::', 'server.socket_port': options.port})