Convert ErrorExit() calls back into an HTTPError exception so it can be properly handled.

Occasionally, AppEngine throws HTTP 500. In practice it's not a big deal but
upload.py converts them into sys.exit() call which is problematic. This breaks
the commit queue since this behaviors forces the CQ to quit.

R=dpranke@chromium.org
BUG=
TEST=


Review URL: http://codereview.chromium.org/9480005

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@123775 0039d316-1c4b-4281-b951-d872f2087c98

rietveld.py

@@ -311,13 +311,27 @@ class Rietveld(object):
 
   def _send(self, request_path, **kwargs):
     """Sends a POST/GET to Rietveld.  Returns the response body."""
+    try:
+      # Sadly, upload.py calls ErrorExit() which does a sys.exit(1) on HTTP
+      # 500 in AbstractRpcServer.Send().
+      old_error_exit = upload.ErrorExit
+      def trap_http_500(msg):
+        """Converts an incorrect ErrorExit() call into a HTTPError exception."""
+        m = re.search(r'(50\d) Server Error', msg)
+        if m:
+          # Fake an HTTPError exception. Cheezy. :(
+          raise urllib2.HTTPError(
+              request_path, m.group(1), e.args[0], None, None)
+        old_error_exit(msg)
+      upload.ErrorExit = trap_http_500
+
       maxtries = 5
       for retry in xrange(maxtries):
         try:
           logging.debug('%s' % request_path)
           result = self.rpc_server.Send(request_path, **kwargs)
-        # Sometimes GAE returns a HTTP 200 but with HTTP 500 as the content. How
+          # Sometimes GAE returns a HTTP 200 but with HTTP 500 as the content.
-        # nice.
+          # How nice.
           return result
         except urllib2.HTTPError, e:
           if retry >= (maxtries - 1):
@@ -332,6 +346,8 @@ class Rietveld(object):
             raise
         # If reaching this line, loop again. Uses a small backoff.
         time.sleep(1+maxtries*2)
+    finally:
+      upload.ErrorExit = old_error_exit
 
   # DEPRECATED.
   Send = get