[converter] Add MergeManifest option to tell converter when manifests are merged

[Fricounet]

Overview

Please briefly describe the changes your pull request makes.

When both the OCI and nydus manifests are merged with nydusify --merge-platform for instance, containerd will try to pull an unpack both images even if it doesn't have a nydus-snapshotter. Which results in the nydus image failing to be unpacked and a global image pull failure. One way to fix this issue is to use a config mediaType that containerd doesn't understand in the nydus image. This way it won't attempt to unpack it while the nydus snapshotter can still discover the image and pull it.

We use application/vnd.nydus.image.config.v1+json as the new config value only used if MergeManifest is set in the MergeOption.

Related Issues

Please link to the relevant issue. For example: Fix #123 or Related #456.

See #669 (comment) for context

Change Details

Please describe your changes in detail:

Test Results

If you have any relevant screenshots or videos that can help illustrate your changes, please add them here.

When propagating the change up to nydusify (see all the changes done in nydusify directly), this will result in an artifact as follow (note the config mediaType):

crane manifest localhost:5000/image:v1.3.0-nydus-platform-config@sha256:4aaffab81483a36fa808f16c0476c6968ce042e6ad7fd734b79f497a0591730d
{
  "schemaVersion": 2,
  "mediaType": "application/vnd.oci.image.manifest.v1+json",
  "config": {
    "mediaType": "application/vnd.nydus.image.config.v1+json",
    "digest": "sha256:3c374743d776cfe42e92a6795e788ec9d3bf2ec7a30dc3a263b37ee433045083",
    "size": 8712
  },
  "layers": [
    {
      "mediaType": "application/vnd.oci.image.layer.nydus.blob.v1",
      "digest": "sha256:a2fec6caf440b76f26fa3366fa2f4e4b31af4e27572acc8d571afc244dd01c5d",
      "size": 8389,
      "annotations": {
        "containerd.io/snapshot/nydus-blob": "true"
      }
    },
    {
      "mediaType": "application/vnd.oci.image.layer.nydus.blob.v1",
      "digest": "sha256:78b1c6220ef98ad2518018d11f35dd391e186f7efc48ac7fa1946278b9334aff",
      "size": 56627718,
      "annotations": {
        "containerd.io/snapshot/nydus-blob": "true"
      }
    },
...

Change Type

Please select the type of change your pull request relates to:

• Bug Fix
• Feature Addition
• Documentation Update
• Code Refactoring
• Performance Improvement
• Other (please describe)

Self-Checklist

Before submitting a pull request, please ensure you have completed the following:

• I have run a code style check and addressed any warnings/errors.
• I have added appropriate comments to my code (if applicable).
• I have updated the documentation (if applicable).
• I have written appropriate unit tests.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 20.62%. Comparing base (d2c042a) to head (fe9ac56).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/converter/convert_unix.go	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #674      +/-   ##
==========================================
- Coverage   20.62%   20.62%   -0.01%     
==========================================
  Files         122      122              
  Lines       13706    13709       +3     
==========================================
  Hits         2827     2827              
- Misses      10561    10564       +3     
  Partials      318      318              

Files with missing lines	Coverage Δ
pkg/converter/types.go	0.00% <ø> (ø)
pkg/converter/convert_unix.go	0.00% <0.00%> (ø)

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[imeoer]

Thanks!