[Django] #32844: Cached pages can crash on 3.1 to 3.2 upgrade
Django
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Reporter: Iuri de Silvio | Owner: nobody
Type: Uncategorized | Status: new
Component: Uncategorized | Version: 3.2
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
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My cached page from 3.1 crashes because I have a middleware setting a
header.
Because cache_page do a pickle caching, we have a 3.1 JsonResponse running
on 3.2, without the new headers feature.
{{{
AttributeError: 'JsonResponse' object has no attribute 'headers'
File "django/core/handlers/exception.py", line 47, in inner
response = get_response(request)
File "commons/middleware.py", line 44, in __call__
response['X-Current-Version'] = VERSION
File "django/http/response.py", line 172, in __setitem__
self.headers[header] = value
}}}
Docs could provide some help about this, the fix should be easy cleaning
specific cache or using `CACHE_MIDDLEWARE_KEY_PREFIX`. that is
unfortunately broken.
https://code.djangoproject.com/ticket/32841
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Ticket URL: <https://code.djangoproject.com/ticket/32844>
Django <https://code.djangoproject.com/>
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Django
Reporter: Iuri de Silvio | Owner: nobody
Component: Documentation | Version: 3.2
Severity: Normal | Resolution: wontfix
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by Carlton Gibson):
* status: new => closed
* resolution: => wontfix
* component: Uncategorized => Documentation
* type: Uncategorized => Bug
Comment:
Hi.
> ...we have a 3.1 JsonResponse running on 3.2...
I can't see how that's ever going to be supported. The response API
doesn't change often but if it does you'll have to clear the cache. You
note this:
> ...fix should be easy cleaning specific cache...
This seems a bit particular to merit specific documentation.
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Ticket URL: <https://code.djangoproject.com/ticket/32844#comment:1>
Django
Reporter: Iuri de Silvio | Owner: nobody
Component: Documentation | Version: 3.2
Severity: Normal | Resolution: wontfix
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Comment (by Simon Charette):
FWIW we've used the `KEY_FUNCTION`
[https://docs.djangoproject.com/en/3.2/ref/settings/#std:setting-CACHES-
KEY_FUNCTION setting] to namespace keys of `CACHES` entries doing rich
object serde by Django major version to prevent these issues from
happening. You have to be careful to do a progressive rollout to prevent
cache miss stampedes but it completely avoids these kinds of issues.
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Ticket URL: <https://code.djangoproject.com/ticket/32844#comment:2>
Django
Reporter: Iuri de Silvio | Owner: nobody
Component: Documentation | Version: 3.2
Severity: Normal | Resolution: wontfix
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Comment (by Iuri de Silvio):
I didn't knew about this `KEY_FUNCTION`.
It would be a problem in my case because we have other keys in the same
cache, but not difficult to move to a different cache and use that.
Thanks!
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Ticket URL: <https://code.djangoproject.com/ticket/32844#comment:3>