#30599: ManifestFilesMixin read_manifest swallows OSError that prevents template
rendering
-------------------------------------------+------------------------
Reporter: Matt Layman | Owner: nobody
Type: Uncategorized | Status: new
Component: Template system | Version: 2.2
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 |
-------------------------------------------+------------------------
While using the ManifestStaticFilesStorage, I encountered the ValueError
shown below.
{{{
<trim>
File "/<some venv>/site-packages/django/contrib/staticfiles/storage.py",
line 134, in _url
hashed_name = hashed_name_func(*args)
File "/<some venv>/site-packages/django/contrib/staticfiles/storage.py",
line 422, in stored_name
raise ValueError("Missing staticfiles manifest entry for '%s'" %
clean_name)
ValueError: Missing staticfiles manifest entry for 'images/twitter.png'
}}}
Further debugging showed that staticfile_storage.hashed_files was empty.
This was odd to me because staticfiles.json existed on my system in its
proper location in STATIC_ROOT. Additionally, the 'images/twitter.png'
existed as a key in the staticfiles.json so I was very confused.
I did more debugging of the manifest loading process and hit the root
problem. Reading the manifest file raised a PermissionError because the
user account running the Django app did not have proper permission to read
from where the file was stored on the filesystem. Unfortunately,
https://github.com/django/django/blob/master/django/contrib/staticfiles/storage.py#L385
catches any OSError and proceeds by returning no content.
This was in a Vagrant virtual machine so I switched to the root user to
bypass any permission errors and the manifest loading worked. I confirmed
that I was able to load a page without any issue.
I'd like to suggest that ManifestFilesMixin.read_manifest either a) not
catch OSError at all to let the system fail so a developer can fix it, b)
have more granular error handling of different OSError exception
subclasses, or c) do some kind of logging to hint to the app developer
that there was a problem.
I'm making this suggestion because catching this error and proceeding left
the app in an unrecoverable state. The ValueError listed at the beginning
of the issue was actually a side effect of the deeper underlying
PermissionError problem from attempting to read the manifest file.
If there is any more info you need from me, please let me know. Thanks!
--
Ticket URL: <https://code.djangoproject.com/ticket/30599>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/051.fd7425cf048d3e719268e326d5a46227%40djangoproject.com.
For more options, visit https://groups.google.com/d/optout.
