Re: URGENT main url path: "/", not serving.. but getting 200 response

[Matthew Blain]

Typically a 204 with nothing run is simply a signal that your content
has been cached elsewhere in Google's network. If you responded with
cache-control: public with a max-age of something, it may be cached
until that expires.
Without futher info (such as an appid or the domain), it's hard to
tell what's going on.

On Apr 27, 11:34 am, Gregory Nicholas <faction.greg...@gmail.com>
wrote:
> really need help.. i'm at a place where i can't really fix this on my own..
> it's 11:00am.. been trouble shooting this since 9pm last night (thank god
> for adderall)
>
> *Preface (kinda):*
>
>    - we've been working with appengine for a couple years now (haven't seen
>    everything, but been through a lot of troubleshooting)
>    - python 2.7, webapp 2.3, django 1.2, HRD
>    - absolutely NO issues with local dev environ, production issue only
>
> *Issue / Symptoms:*
>
>    - only the main url path: "/" for my app domain is not serving the
>    request to my app
>    - essentially breaks down to only the home page not working on
>    http://www.<domainname>.com
>    - the main url path for the appspot
>    domain: http://<domainname>.appspot.com serves
>       - request is routed properly from the app.yaml to my request handler
>    - on http://<domainname>.com, any request to a subpath STILL WORKS!
>       - ex: http://< domainname >.com/user/login serves, works
>    - the request IS hitting my application:
>       - attached is a screen shot of my app logs, where the main path serves
>          - not hitting my app.yaml file, and not routed to any request
>          handlers
>          - appears as though my code is never being executed for the request
>
> *What I've tried:*
>
>    - i telnet'ed and tracerouted the domain name to rule out it being a DNS
>    issue
>       - see attached terminal screenshot
>    - i've redeployed my app several times
>    - i reverted the default version to a previous version
>    - i've shutdown any instances several times
>    - i switched from automatic instance allocation to manual, switching
>    from F1 to F2 classes
>
> PLEASE HELP!!!
>
>  Screen Shot 2012-04-27 at 11.14.15 AM.png
> 193KViewDownload
>
>  Screen Shot 2012-04-27 at 11.31.23 AM.png
> 156KViewDownload

[Joshua Smith]

You could test this theory by hitting /?foo

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[Gregory Nicholas]

yep.. bingo.. what are my options from here?

[Gregory Nicholas]

by bingo i meant that was the request with the /? worked indeed..

dare i ask on options to cache bust?

[Joshua Smith]

Let's review:

Google has cached a blank version of your / page.

The blank page is only about 12 hours old. The max-age is set to 1 year. So this problem will go away on its own in a year.

It really sucks to be you right now. :(

You should try really, really hard to figure out how this happened. I've never heard of anything like this on these lists, so it's likely that it's a bug in your code someplace that can yield blank page with a 1 year timeout.

If you repeat that telnet session, you can probably figure out more exactly when the page was cached, then you can look at your logs to figure out what caused it. Maybe.

Getting the problem cleared would require some manual intervention from google. They'd have to manually invalidate that cache entry. I'd bet money that the Google App Engine team has no ability whatever to cause that to happen. Upgrade to a $500/month enterprise account perhaps?

I've been trying to think of a way to fix this using DNS, but I'm coming up empty, short of changing your domain name.

-Joshua

[Barry Hunter]

Because its apparent there has been a blank version of the page cached
in edge-cache.

Can you perhaps hardcode your domain to go though a different
edge-cache? (ie put the www. as a A record to a different IP at the
DNS level.)

There are apprently a few of them
http://just-ping.com/index.php?vh=ghs.google.com&c=&s=ping%21


... because you havent revealed your domain name, we can't help you
find an edge-cache that has a valid copy.


(alternativly put the domain though some other CDN. Ie bypass Google
Apps and the Google Edge Cache altogether. It can proxy your appspot
URL - which is working ok)

[alex]

I think you can actually do it without manual intervention from Google internally:

Let's say your app (with cached blank page) is currently accessible as www.example.org

1. make sure you remove "cache-control: public ..." headers from the response

2. add a mapping that will make your app accessible as app.example.org

3. like Joshua suggested, change www CNAME into www A DNS record pointing somewhere else, where you do a simple (maybe even permanent) redirect to app.example.org

Even though it seems like your blank page is cached for a long time now, www DNS record will expire sooner (normally 24 ours if you haven't changed TTL)

Hope that helps.

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[alex]

Oops. Sorry, it was Barry suggesting DNS change.

[Richard Watson]

What if Gregory put (e.g.) Cloudflare in front of the app and used it to fetch "app" requests and serve them as "www" (I assume that's possible).  This way, people continue to see www and can add www links.  Can try it as a short-term solution while you tinker with the setup and/or wait for the edge cache to sort itself out.

It's quite possible that Google's edge cache caches for a maximum period shorter than a year due to demand/bandwidth priorities, so maybe this'll be solved in a week or month.

On Saturday, April 28, 2012 10:13:26 AM UTC+2, alex wrote:

[Gregory Nicholas]

Richard Watson's post was money.. ackkk.. someone unwittingly let the cache-control header slip into a base request handler.. thnx everyone..

[Joshua Smith]

Another thought: Perhaps if you just redirect your DNS to a "Down for Maintenance" page (not served by google) for a while, the cached page will be evicted sooner because nobody is hitting it...