The blobs annotation in manifest should be deprecated

[imeoer]

Reference: https://github.com/containerd/nydus-snapshotter/issues/5

[bergwolf]

Can we have a replacement that still enables us to get the blob list statically? It is a bit heavy to run nydusd just to get the blob list. I understand that nydus-snapshotter can do it via nydusd, I'm more thinking about static analysis of nydus images.

[imeoer]

An alternative is to use the static inspect tool, for example:

$ nydus-image inspect --bootstrap ~/bootstrap -R blobs                                                                                                                     
[{"blob_id":"x","compressed_size":0,"decompressed_size":0,"readahead_offset":0,"readahead_size":0}]

[luodw]

Maybe we can add another blob layer xxx, it contains blob id list and has annotation "containerd.io/snapshot/nydus-blob-ids=true". When create container, snapshot find nydus meta layer and blob_ids layer in the meantime in func findNydusMetaLayer so as to reduse find overhead. So, we can read blob id list in the right snapshot.

[imeoer]

@luodw The blob layer should exist on manifest if using the registry as blob storage backend, so the blobs annotation is mainly used on referencing the blobs stored on another storage backend (for example oss).

[luodw]

@imeoer I known, I mean we can add blob ids_list layer to manifest just like meta layer. So it can also download from storage backend and unpack.

[imeoer]

@luodw Ok, I see your point, but I don't think it's necessary to have the blob list as a layer entity, if we do that, the snapshotter needs to handle it additionally, which would be a more complicated change for nydus format.

[changweige]

@imeoer Shall we close this now since the label has been dropped from nydus image and related PR has been merged

[imeoer]

@changweige Ok, thanks for solving the issue.