new_empty_manifest: create a valid manifest with an empty config desc… #31
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…riptor The empty descriptor is described in the image spec [1]. `new_empty_manifest` writes an empty config descriptor in the blobs directory, which results in a valid image layout specification. This is validated using the fsck function in the `test_new_empty_manifest` test. Fixes bootc-dev#27 [1] https://github.com/opencontainers/image-spec/blob/main/manifest.md#guidance-for-an-empty-descriptor Signed-off-by: Ariel Miculas-Trif <amiculas@cisco.com>
| /// Returned when the OCI Image Index (index.json) is missing | ||
| MissingImageIndex, | ||
| #[error("Unexpected media type {media_type}")] | ||
| /// Returned when the OCI Image Index (index.json) is missing |
| let _: ImageConfiguration = self.read_json_blob(manifest.config())?; | ||
| } | ||
| MediaType::EmptyJSON => { | ||
| let _: EmptyDescriptor = self.read_json_blob(manifest.config())?; |
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If we do the below ⬇️ then I think we can just no-op here.
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| if !self | ||
| .dir | ||
| .exists(OciDir::parse_descriptor_to_path(&empty_descriptor)?) |
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Hmm actually I think the intent of adding a dedicated media type for this is that we don't need to store it, we could just synthesize it on demand right?
I guess if we don't store it then people calling read_json_blob on that type would get an error...but we can just tell them "don't do that"?
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Well the reason for writing it to the disk is that I currently use an empty config for PuzzleFS, but skopeo won't copy the image if it detects that not all the descriptors are present in 'blobs/sha256' (even though I store the data inline, in the descriptor, as a base64 encoded empty json). So without writing the blob we end up with an image that's not conformant to the spec.
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Right, sorry for making you repeat that. I think that's arguably a minor bug in skopeo but yep let's be compatible with it!
Now that [1] was merged into ocidir-rs, we can use the new_empty_manifest function and we'll get a valid OCI image with an empty config descriptor. [1] bootc-dev/ocidir-rs#31 Signed-off-by: Ariel Miculas-Trif <amiculas@cisco.com>
Now that [1] was merged into ocidir-rs, we can use the new_empty_manifest function and we'll get a valid OCI image with an empty config descriptor. [1] bootc-dev/ocidir-rs#31 Signed-off-by: Ariel Miculas-Trif <amiculas@cisco.com>
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…riptor
The empty descriptor is described in the image spec [1].
new_empty_manifestwrites an empty config descriptor in the blobs directory, which results in a valid image layout specification. This is validated using the fsck function in thetest_new_empty_manifesttest.Fixes #27
[1] https://github.com/opencontainers/image-spec/blob/main/manifest.md#guidance-for-an-empty-descriptor