Rudder

The reason for this is the way the "loading" page is implemented: it is a special page served by Apache in case a 503 error would be returned. The page served then causes a reload to happen every 4 seconds, to see if the application is ready and the 503 has gone away.

But Chrome seems to be "clever" and catch this. We should change something here...

Maybe we should reduce time before reloading the page ? Or should we redirect to a remote URL instead of a local file ?

    "Note that when you specify an ErrorDocument
    that points to a remote URL (ie. anything with a method such as
    http in front of it), Apache will send a redirect to the
    client to tell it where to find the document, even if the
    document ends up being on the same server. This has several
    implications, the most important being that the client will not
    receive the original error status code, but instead will
    receive a redirect status code. This in turn can confuse web
    robots and other clients which try to determine if a URL is
    valid using the status code. In addition, if you use a remote
    URL in an ErrorDocument 401, the client will not
    know to prompt the user for a password since it will not
    receive the 401 status code. Therefore, if you use an
    ErrorDocument 401 directive then it must refer to a local
    document." 

Matthieu, we think this can be worked around with an Apache config to send a 200 return code instead of 503. can you investigate?

Matthieu, could you investigate on this ticket please ?

According to this doc (Chromium): http://www.chromium.org/throttling

We should add a "X-Chrome-Exponential-Throttling: disable" header in the Apache response to prevent this.

Note, on old Chrome version, disabling this behavior server-side is not possible: http://www.chromium.org/throttling/anti-ddos-http-throttling-in-older-versions-of-chrome

And masking the 502 error code from Jetty with a 200 with Apache does not seem to be something normal (very little doc about this).

We can solve this by adding the following entry, requiring mod_headers:

   <LocationMatch "/rudder">
      Header add X-Chrome-Exponential-Throttling "disable" 
   </LocationMatch>

Is this an acceptable solution ?

PR available.

Be careful and commit http://www.rudder-project.org/redmine/issues/3534 first !!!

Applied in changeset 4c876f0add36579150a28c0c36b417ab531c4f4b.