UnicodeDecodeError when syncing specific image

[Thibf]

When trying to sync a specific image, a unicode error show up.
Not sure if my usage is correct.

# uvt-simplestreams-libvirt sync --source http://cloud-images.ubuntu.com/releases --path=focal/release-20231011/ubuntu-20.04-server-cloudimg-amd64.img release=focal arch=amd64
Traceback (most recent call last):
  File "/usr/bin/uvt-simplestreams-libvirt", line 27, in <module>
    uvtool.libvirt.simplestreams.main()
  File "/usr/lib/python3/dist-packages/uvtool/libvirt/simplestreams.py", line 332, in main
    args.func(args)
  File "/usr/lib/python3/dist-packages/uvtool/libvirt/simplestreams.py", line 266, in main_sync
    tmirror.sync(smirror, initial_path)
  File "/usr/lib/python3/dist-packages/simplestreams/mirrors/__init__.py", line 85, in sync
    content, payload = reader.read_json(path)
                       ^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/simplestreams/mirrors/__init__.py", line 42, in read_json
    raw = source.read().decode('utf-8')
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xfb in position 3: invalid start byte

[Robie Basak (racb)]

Hi,

--path is expected to point to JSON, not the raw image URL.

The point of uvt-simplestreams-libvirt is to sync against a simplestreams source, so it doesn't make sense to give it a raw image URL directly. If you want to do that, you can just use wget and the --backing-image-file option to "uvt-kvm create" for example.

If you want to pull a specific image or set of images with uvt-simplestreams-libvirt then you're supposed to specify the metadata criteria precisely. You can use sstream-query to test. For example:

sstream-query http://cloud-images.ubuntu.com/releases release=focal arch=amd64 version_name=20231011 ftype=disk1.img

This provides a single image, so this should work:

uvt-simplestreams-libvirt sync --source http://cloud-images.ubuntu.com/releases release=focal arch=amd64 version_name=20231011 ftype=disk1.img

Hope that helps!