Hi,
My colleague is having the issue outlined below. I thought this list might be
better to give an insight as to what is going on?
Begin forwarded message:
> From: Adam Terrey <a...@pretaweb.com>
> Subject: Fwd: Zope/Plone/Zeo Concurrency Issue
> Date: 28 May 2013 5:23:33 PM AEST
> To: Dylan Jay <d...@pretaweb.com>
>
>
>
>
> -------- Original Message --------
> Subject: Zope/Plone/Zeo Concurrency Issue
> Date: Tue, 28 May 2013 16:04:21 +1000
> From: Adam Terrey <a...@pretaweb.com>
> To: z...@zope.org
>
> Hi,
>
> Can someone offer some insight into what might be going on here and perhaps
> how I can debug the following issue?
>
> In Plone there is a request patten used to create content which looks like...
> (A) GET request to /MySite/createObject?type_name=Document
> Responds with a redirect to a tempory document at a location such as
> /MySite/portal_factory/Document/document.2013-05-28.1878040976/edit
> (B) GET /MySite/portal_factory/Document/document.2013-05-28.1878040976/edit
> Responds with from to set fields in the Document
> (C) POST request to
> /MySite/portal_factory/Document/document.2013-05-28.1878040976/atct_edit
> Responds with a redirect to the final location of the document such as
> /Mysite/my-page
> (D) GET /Mysite/my-page
> Responds with the newly created page
> In one of our production systems we are running multiple Zope/Plone instances
> connecting to a Zeo server. And the above patten works about 95% of the time.
> However, sometimes request (D) will respond with 404 Page Not Found. My
> assumptions is that request (C) and (D) are going to different instances and
> somehow the instance handling request (D) does not yet see the
> transaction with completed the page creation.
> I've checked that the transaction commit happens before response headers are
> emitted for request (C) - suspecting the case that the browser handles the
> redirect before the transaction is completed - but this is clearly not the
> case from what i can see. The transaction is well committed before response
> headers are returned.
>
> Versions are as follows:
> Plone 4.1.3 (4112)
> CMF 2.2.4
> Zope 2.13.10
> Python 2.7.2+ (default, Oct 4 2011, 20:06:09) [GCC 4.6.1]
> I have been using the following script to recreate the issue. I seem to be
> able to produce the error quicker if I put server2 under apache-bench load,
> and I have been able to recreate the issue on a local copy of our production
> system but it is a far more rare case.
>
> auth = ('admin', 'admin')
> server1 = 'http://localhost:46101'
> server2 = 'http://localhost:46102'
> site = '/Plone'
>
> import requests
>
> ses = requests.Session()
> ses.auth=auth
>
> for i in range(10):
>
> # Create tempory Object
> create_url = server1 + site + '/createObject?type_name=Document'
> print "GET", create_url
> res = ses.get (create_url)
> tempory_obj = res.url.rsplit("/", 1)[0]
> print "tempory object:", tempory_obj
>
>
> # Submit data to create object (response will
> # be the redirect ot the ojbect's location)
>
> data = {
> 'id': '',
> 'title': 'page' + str(i) ,
> 'form.button.save': 'Save',
> 'form.submitted': '1',
> "description": "some secriot",
> "text": "some text"
> }
>
> post_url = tempory_obj + "/atct_edit"
> print "POST", post_url
> res = ses.post(post_url, data=data, allow_redirects=False)
>
> redirect_location = "/" + res.headers['location'][7:].split('/',1)[1]
> print 'redirect_location', redirect_location
>
>
> # Request object from the redirect from server2
> redirect_url = server2 + redirect_location
> print "GET", redirect_url
> res = ses.get(redirect_url)
>
> if res.status_code != 200:
> last404 = res
> print res;
> break;
>
> print "---"
>
>
> Any help would be appreciated.
>
> Regards,
>
> --
> Adam Terrey
> Software Engineer
> PretaWeb
>
> a...@pretaweb.com
>
>
>
>
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