Unreachable 'ImageSizeLimitExceeded' exception block in stage call

[Abhishek Kekane]

ImageSizeLimitExceeded exception block [1] is unreachable in stage because
we are using sotre_backend.add (filesystem.add in this case) and it will
raise 'exceptions.StorageFull()' [2] if image file is too large (errno.EFBIG).

[1] https://github.com/openstack/glance/blob/master/glance/api/v2/image_data.py#L323
[2] https://github.com/openstack/glance_store/blob/master/glance_store/_drivers/filesystem.py#L691

[Brian Rosmaita (brian-rosmaita)]

I think Abhishek's analysis is correct. The upload() function, which also catches this exception, eventually uses some kind of limiting reader to store the image data, which is why it needs to catch ImageSizeLimitExceeded. But stage() is using store.add() directly, so it won't see that.

As a side point, the current import workflow will allow an end user to stage something super enormous; the size limit isn't checked until the import call happens. Just wanted to mention that.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/521411

[Erno Kuvaja (jokke)]

Actually I'm not sure if that block is unreachable. The stage should utilize same mechanism for getting the data stream as upload and utilize the same limiting reader. If it does not _that_ is the actual bug as that's the only thing that is enforcing the image size limitation from our configuration.

[Abhishek Kekane (abhishek-kekane)]

Hi Erno,

As per your suggestion I have used LimitingReader and ensured that it will raise ImageSizeLimitExceeded if image size is greater than 'image_size_cap' set in the glance-api.conf

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/521411
Committed: https://git.openstack.org/cgit/openstack/glance/commit/?id=d48c8419ee73de275963f448a6718ff75f90a589
Submitter: Zuul
Branch: master

commit d48c8419ee73de275963f448a6718ff75f90a589
Author: Abhishek Kekane <email address hidden>
Date: Mon Nov 20 03:44:23 2017 +0000

    Utilize LimitingReader for staging data

    ImageSizeLimitExceeded exception block is unreachable in stage
    call because glance is using sotre_backend.add (filesystem.add
    in this case) and it will raise 'exceptions.StorageFull()' [1]
    if image file is too large (errno.EFBIG).

    Used LimitingReader to enforce the image size limitation which
    will raise ImageSizeLimitExceeded if image size is larger that
    config option 'image_size_cap'.

    [1] https://github.com/openstack/glance_store/blob/master/glance_store/_drivers/filesystem.py#L691

    Change-Id: I50821111ac4c782966ed1ccd48e92f8dd4100e62
    Closes-Bug: #1732830

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/glance 16.0.0.0b2 development milestone.