On Wed, May 20, 2015 at 5:06 PM, Daniel P. Berrange <berra...@redhat.com> wrote: > On Wed, May 20, 2015 at 12:01:37AM +0200, Flavio Percoco wrote: >> On 19/05/15 17:19 +0100, Daniel P. Berrange wrote: >> >In Nova we are attempting to model[1] the glance image metadata and >> >properties using the Nova object model (now oslo.versionedobjects). >> > >> >The one item I'm stuck on understanding is the 'locations' field >> >and more specifically the 'metadata' element in each location >> >entry >> > >> > >> >In the file glance/api/v2/images.py I can see this description >> >of the data format: >> > >> > 'locations': { >> > 'type': 'array', >> > 'items': { >> > 'type': 'object', >> > 'properties': { >> > 'url': { >> > 'type': 'string', >> > 'maxLength': 255, >> > }, >> > 'metadata': { >> > 'type': 'object', >> > }, >> > }, >> > 'required': ['url', 'metadata'], >> > }, >> > 'description': _('A set of URLs to access the image file kept in >> > ' >> > 'external store'), >> > >> > >> >As you can see here, 'metadata' is just said to be of type 'object'. >> > >> >Is there somewhere that actually describes what is valid contents >> >for this field ? Is it sufficient to assume the metadata will only >> >ever be a dict of strings, or can the metadata be a complex type >> >with arbitrarily nested data structures ? >> >> It's just arbitrary metadata for now, we don't have a specific format. >> I'm curious to know if there are folks using this field. We do (did) >> have a use case for it. > > Yep, I'd be curious to understand just what it is used for in practice ? > Is the data to be stored in there determined by python code, or by the > local administrator or both ? > > > Regards, > Daniel > -- > |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| > |: http://libvirt.org -o- http://virt-manager.org :| > |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| > |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| > > __________________________________________________________________________ > OpenStack Development Mailing List (not for usage questions) > Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
Yes, It determined by python code in nova as a part of image download plugin, and administrator needs to prepare it based on particular deployment environment as well. Current a usage is to accelerate image download from nfs store to nova compute node, now there is only one particular plugin in nova upstream tree [0]. (from the logic in _file_system_lookup(), i think a predefined 'id' is needed in the metadata of the location entry). [0] https://github.com/openstack/nova/blob/master/nova/image/download/file.py#L150 zhiyan __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev