Add ability to set layer media type for artifacts

in #25884, it was pointed out that the standard detection used to
determine the artifact's file type can be wrong.  in those cases, it
would be handy for the user to be able to override the media type of the
layer.  as such, added a new option called `--file-type`, which is
optional, and allows users to do just that.

`podman artifact add --file-type text/yaml
quay.io/artifact/config:latest ./config.yaml `

Fixes: #25884

Signed-off-by: Brent Baude <bbaude@redhat.com>

cmd/podman/artifact/add.go

@@ -19,8 +19,10 @@ var (
 		RunE:              add,
 		Args:              cobra.MinimumNArgs(2),
 		ValidArgsFunction: common.AutocompleteArtifactAdd,
-		Example:           `podman artifact add quay.io/myimage/myartifact:latest /tmp/foobar.txt`,
+		Example: `podman artifact add quay.io/myimage/myartifact:latest /tmp/foobar.txt
-		Annotations:       map[string]string{registry.EngineMode: registry.ABIMode},
+podman artifact add --file-type text/yaml quay.io/myimage/myartifact:latest /tmp/foobar.yaml
+podman artifact add --append quay.io/myimage/myartifact:latest /tmp/foobar.tar.gz`,
+		Annotations: map[string]string{registry.EngineMode: registry.ABIMode},
 	}
 )
 
@@ -28,6 +30,7 @@ type artifactAddOptions struct {
 	ArtifactType string
 	Annotations  []string
 	Append       bool
+	FileType     string
 }
 
 var (
@@ -51,6 +54,10 @@ func init() {
 
 	appendFlagName := "append"
 	flags.BoolVarP(&addOpts.Append, appendFlagName, "a", false, "Append files to an existing artifact")
+
+	fileTypeFlagName := "file-type"
+	flags.StringVarP(&addOpts.FileType, fileTypeFlagName, "", "", "Set file type to use for the artifact (layer)")
+	_ = addCmd.RegisterFlagCompletionFunc(fileTypeFlagName, completion.AutocompleteNone)
 }
 
 func add(cmd *cobra.Command, args []string) error {
@@ -63,6 +70,7 @@ func add(cmd *cobra.Command, args []string) error {
 	opts.Annotations = annots
 	opts.ArtifactType = addOpts.ArtifactType
 	opts.Append = addOpts.Append
+	opts.FileType = addOpts.FileType
 
 	report, err := registry.ImageEngine().ArtifactAdd(registry.Context(), args[0], args[1:], opts)
 	if err != nil {

docs/source/markdown/podman-artifact-add.1.md.in

@@ -27,6 +27,10 @@ Note: Set annotations for each file being added.
 
 Append files to an existing artifact. This option cannot be used with the **--type** option.
 
+#### **--file-type**
+
+Set the media type of the artifact file instead of allowing detection to determine the type
+
 #### **--help**
 
 Print usage statement.
@@ -55,6 +59,16 @@ Set an annotation for an artifact
 $ podman artifact add --annotation date=2025-01-30 quay.io/myartifact/myml:latest /tmp/foobar1.ml
 ```
 
+Append a file to an existing artifact
+```
+$ podman artifact add --append quay.io/myartifact/tarballs:latest /tmp/foobar.tar.gz
+```
+
+Override the media type of the artifact being added
+```
+$ podman artifact add --file-type text/yaml quay.io/myartifact/descriptors:latest /tmp/info.yaml
+```
+
 
 ## SEE ALSO
 **[podman(1)](podman.1.md)**, **[podman-artifact(1)](podman-artifact.1.md)**

pkg/domain/entities/artifact.go

@@ -13,6 +13,7 @@ type ArtifactAddOptions struct {
 	Annotations  map[string]string
 	ArtifactType string
 	Append       bool
+	FileType     string
 }
 
 type ArtifactExtractOptions struct {

pkg/domain/infra/abi/artifact.go

@@ -192,6 +192,7 @@ func (ir *ImageEngine) ArtifactAdd(ctx context.Context, name string, paths []str
 		Annotations:  opts.Annotations,
 		ArtifactType: opts.ArtifactType,
 		Append:       opts.Append,
+		FileType:     opts.FileType,
 	}
 
 	artifactDigest, err := artStore.Add(ctx, name, paths, &addOptions)

pkg/libartifact/store/store.go

@@ -251,20 +251,26 @@ func (as ArtifactStore) Add(ctx context.Context, dest string, paths []string, op
 	// ImageDestination, in general, requires the caller to write a full image; here we may write only the added layers.
 	// This works for the oci/layout transport we hard-code.
 	for _, path := range paths {
+		mediaType := options.FileType
 		// get the new artifact into the local store
 		newBlobDigest, newBlobSize, err := layout.PutBlobFromLocalFile(ctx, imageDest, path)
 		if err != nil {
 			return nil, err
 		}
-		detectedType, err := determineManifestType(path)
+
-		if err != nil {
+		// If we did not receive an override for the layer's mediatype, use
-			return nil, err
+		// detection to determine it.
+		if len(mediaType) < 1 {
+			mediaType, err = determineManifestType(path)
+			if err != nil {
+				return nil, err
+			}
 		}
 
 		annotations := maps.Clone(options.Annotations)
 		annotations[specV1.AnnotationTitle] = filepath.Base(path)
 		newLayer := specV1.Descriptor{
-			MediaType:   detectedType,
+			MediaType:   mediaType,
 			Digest:      newBlobDigest,
 			Size:        newBlobSize,
 			Annotations: annotations,

pkg/libartifact/types/config.go

@@ -10,6 +10,9 @@ type AddOptions struct {
 	ArtifactType string            `json:",omitempty"`
 	// append option is not compatible with ArtifactType option
 	Append bool `json:",omitempty"`
+	// FileType describes the media type for the layer.  It is an override
+	// for the standard detection
+	FileType string `json:",omitempty"`
 }
 
 // FilterBlobOptions options used to filter for a single blob in an artifact

test/e2e/artifact_test.go

@@ -88,6 +88,7 @@ var _ = Describe("Podman artifact", func() {
 	})
 
 	It("podman artifact add with options", func() {
+		yamlType := "text/yaml"
 		artifact1Name := "localhost/test/artifact1"
 		artifact1File, err := createArtifactFile(1024)
 		Expect(err).ToNot(HaveOccurred())
@@ -96,13 +97,14 @@ var _ = Describe("Podman artifact", func() {
 		annotation1 := "color=blue"
 		annotation2 := "flavor=lemon"
 
-		podmanTest.PodmanExitCleanly("artifact", "add", "--type", artifactType, "--annotation", annotation1, "--annotation", annotation2, artifact1Name, artifact1File)
+		podmanTest.PodmanExitCleanly("artifact", "add", "--file-type", yamlType, "--type", artifactType, "--annotation", annotation1, "--annotation", annotation2, artifact1Name, artifact1File)
 
 		a := podmanTest.InspectArtifact(artifact1Name)
 		Expect(a.Name).To(Equal(artifact1Name))
 		Expect(a.Manifest.ArtifactType).To(Equal(artifactType))
 		Expect(a.Manifest.Layers[0].Annotations["color"]).To(Equal("blue"))
 		Expect(a.Manifest.Layers[0].Annotations["flavor"]).To(Equal("lemon"))
+		Expect(a.Manifest.Layers[0].MediaType).To(Equal(yamlType))
 
 		failSession := podmanTest.Podman([]string{"artifact", "add", "--annotation", "org.opencontainers.image.title=foobar", "foobar", artifact1File})
 		failSession.WaitWithDefaultTimeout()