packager: set OCI layout metadata for direct registry push

.github/workflows/test-packager-inference.yaml

@@ -60,14 +60,22 @@ jobs:
             --build-arg name=llama-3.2-1b-instruct \
             --build-arg layer_packaging=raw \
             --output type=local,dest=modelpack-out
-          test -f modelpack-out/layout/index.json
+          layout_root=modelpack-out
+          if [ ! -f "$layout_root/index.json" ] && [ -f modelpack-out/layout/index.json ]; then
+            layout_root=modelpack-out/layout
+          fi
+          test -f "$layout_root/index.json"
           echo 'Modelpack layout:'
           find modelpack-out -maxdepth 2 -type f | head -50
 
       - name: Push modelpack to local registry
         run: |
           set -euo pipefail
-          skopeo copy --dest-tls-verify=false oci:modelpack-out/layout docker://localhost:5000/aikit/llama-3.2-1b-instruct:modelpack
+          layout_root=modelpack-out
+          if [ ! -f "$layout_root/index.json" ] && [ -f modelpack-out/layout/index.json ]; then
+            layout_root=modelpack-out/layout
+          fi
+          skopeo copy --dest-tls-verify=false oci:$layout_root docker://localhost:5000/aikit/llama-3.2-1b-instruct:modelpack
           skopeo inspect --tls-verify=false --raw docker://localhost:5000/aikit/llama-3.2-1b-instruct:modelpack > pushed-manifest.json
           sha=sha256:$(sha256sum pushed-manifest.json | awk '{print $1}')
           echo "Pushed manifest digest: $sha"

.github/workflows/test-packager.yaml

@@ -106,11 +106,15 @@ jobs:
         run: |
           set -euo pipefail
           dest=out-${{ matrix.case.name }}
+          layout_root="$dest"
+          if [ ! -f "$layout_root/index.json" ] && [ -f "$dest/layout/index.json" ]; then
+            layout_root="$dest/layout"
+          fi
           echo "Listing produced files (truncated)"
           find "$dest" -maxdepth 3 -type f | head -100
           # Check expected key files exist in local output (heuristic)
           if [ '${{ matrix.case.output_mode }}' != 'files' ]; then
-            if [ ! -f "$dest/layout/index.json" ]; then echo "layout/index.json missing (expected for packaged layout)"; exit 1; fi
+            if [ ! -f "$layout_root/index.json" ]; then echo "index.json missing (expected for packaged layout)"; exit 1; fi
           else
             # files mode: ensure at least one non-empty file present
             if ! find "$dest" -type f -maxdepth 2 | head -1 | grep -q . ; then
@@ -125,8 +129,11 @@ jobs:
         run: |
           set -euo pipefail
           dest=out-${{ matrix.case.name }}
-          layout_root="$dest/layout"
-          if [ ! -f "$layout_root/index.json" ]; then echo "layout/index.json missing; cannot treat local output as OCI layout"; ls -R "$dest" | head -200; exit 1; fi
+          layout_root="$dest"
+          if [ ! -f "$layout_root/index.json" ] && [ -f "$dest/layout/index.json" ]; then
+            layout_root="$dest/layout"
+          fi
+          if [ ! -f "$layout_root/index.json" ]; then echo "index.json missing; cannot treat local output as OCI layout"; ls -R "$dest" | head -200; exit 1; fi
           if [ ! -f "$layout_root/oci-layout" ]; then
             echo '{"imageLayoutVersion":"1.0.0"}' > "$layout_root/oci-layout"
           fi
@@ -140,7 +147,11 @@ jobs:
         run: |
           set -euo pipefail
           dest=out-${{ matrix.case.name }}
-          localDigest=$(jq -r '.manifests[0].digest' "$dest/layout/index.json")
+          layout_root="$dest"
+          if [ ! -f "$layout_root/index.json" ] && [ -f "$dest/layout/index.json" ]; then
+            layout_root="$dest/layout"
+          fi
+          localDigest=$(jq -r '.manifests[0].digest' "$layout_root/index.json")
           # Fetch raw manifest (artifact) and compute digest manually (inspect --format is image-specific and fails on artifactType)
           skopeo inspect --tls-verify=false --raw docker://localhost:5000/aikit/${{ matrix.case.name }}:test > remote-manifest.json
           remoteDigest=sha256:$(sha256sum remote-manifest.json | awk '{print $1}')

pkg/packager/build.go

@@ -116,9 +116,16 @@ func BuildModelpack(ctx context.Context, c client.Client) (*client.Result, error
 		llb.Args([]string{"bash", "-c", script}),
 		llb.AddMount("/src", modelState, llb.Readonly),
 	)
-	final := llb.Scratch().File(llb.Copy(run.Root(), "/layout/", "/"))
+	final := llb.Scratch().File(llb.Copy(run.Root(), "/layout", "/", &llb.CopyInfo{
+		CopyDirContentsOnly: true,
+	}))
 
-	return solveAndBuildResult(ctx, c, final, "packager:modelpack")
+	result, err := solveAndBuildResult(ctx, c, final, "packager:modelpack")
+	if err != nil {
+		return nil, err
+	}
+	result.AddMeta("containerimage.oci-layout", []byte("true"))
+	return result, nil
 }
 
 // BuildGeneric builds a generic artifact layout (target packager/generic).
@@ -151,9 +158,16 @@ func BuildGeneric(ctx context.Context, c client.Client) (*client.Result, error)
 		llb.Args([]string{"bash", "-c", script}),
 		llb.AddMount("/src", srcState, llb.Readonly),
 	)
-	final := llb.Scratch().File(llb.Copy(run.Root(), "/layout/", "/"))
+	final := llb.Scratch().File(llb.Copy(run.Root(), "/layout", "/", &llb.CopyInfo{
+		CopyDirContentsOnly: true,
+	}))
 
-	return solveAndBuildResult(ctx, c, final, "packager:generic")
+	result, err := solveAndBuildResult(ctx, c, final, "packager:generic")
+	if err != nil {
+		return nil, err
+	}
+	result.AddMeta("containerimage.oci-layout", []byte("true"))
+	return result, nil
 }
 
 func getBuildArg(opts map[string]string, k string) string {