Add platform selection (#866)

syft/source/image_metadata.go

@@ -15,6 +15,9 @@ type ImageMetadata struct {
 	RawManifest    []byte          `json:"manifest"`
 	RawConfig      []byte          `json:"config"`
 	RepoDigests    []string        `json:"repoDigests"`
+	Architecture   string          `json:"architecture"`
+	Variant        string          `json:"architectureVariant,omitempty"`
+	OS             string          `json:"os"`
 }
 
 // LayerMetadata represents all static metadata that defines what a container image layer is.
@@ -42,6 +45,9 @@ func NewImageMetadata(img *image.Image, userInput string) ImageMetadata {
 		RawConfig:      img.Metadata.RawConfig,
 		RawManifest:    img.Metadata.RawManifest,
 		RepoDigests:    img.Metadata.RepoDigests,
+		Architecture:   img.Metadata.Architecture,
+		Variant:        img.Metadata.Variant,
+		OS:             img.Metadata.OS,
 	}
 
 	// populate image metadata

syft/source/source.go

@@ -40,12 +40,13 @@ type Input struct {
 	Scheme                          Scheme
 	ImageSource                     image.Source
 	Location                        string
+	Platform                        string
 	autoDetectAvailableImageSources bool
 }
 
 // ParseInput generates a source Input that can be used as an argument to generate a new source
 // from specific providers including a registry.
-func ParseInput(userInput string, detectAvailableImageSources bool) (*Input, error) {
+func ParseInput(userInput string, platform string, detectAvailableImageSources bool) (*Input, error) {
 	fs := afero.NewOsFs()
 	scheme, source, location, err := DetectScheme(fs, image.DetectSource, userInput)
 	if err != nil {
@@ -71,12 +72,17 @@ func ParseInput(userInput string, detectAvailableImageSources bool) (*Input, err
 		}
 	}
 
+	if scheme != ImageScheme && platform != "" {
+		return nil, fmt.Errorf("cannot specify a platform for a non-image source")
+	}
+
 	// collect user input for downstream consumption
 	return &Input{
 		UserInput:                       userInput,
 		Scheme:                          scheme,
 		ImageSource:                     source,
 		Location:                        location,
+		Platform:                        platform,
 		autoDetectAvailableImageSources: detectAvailableImageSources,
 	}, nil
 }
@@ -147,10 +153,19 @@ func getImageWithRetryStrategy(in Input, registryOptions *image.RegistryOptions)
 		opts = append(opts, stereoscope.WithRegistryOptions(*registryOptions))
 	}
 
+	if in.Platform != "" {
+		opts = append(opts, stereoscope.WithPlatform(in.Platform))
+	}
+
 	img, err := stereoscope.GetImageFromSource(ctx, in.Location, in.ImageSource, opts...)
+	cleanup := func() {
+		if err := img.Cleanup(); err != nil {
+			log.Warnf("unable to cleanup image=%q: %w", in.UserInput, err)
+		}
+	}
 	if err == nil {
 		// Success on the first try!
-		return img, stereoscope.Cleanup, nil
+		return img, cleanup, nil
 	}
 
 	scheme := parseScheme(in.UserInput)
@@ -180,11 +195,12 @@ func getImageWithRetryStrategy(in Input, registryOptions *image.RegistryOptions)
 		in.ImageSource = image.DetermineDefaultImagePullSource(in.UserInput)
 	}
 	img, err = stereoscope.GetImageFromSource(ctx, in.UserInput, in.ImageSource, opts...)
-	if err != nil {
-		return nil, nil, err
+	cleanup = func() {
+		if err := img.Cleanup(); err != nil {
+			log.Warnf("unable to cleanup image=%q: %w", in.UserInput, err)
+		}
 	}
-
-	return img, stereoscope.Cleanup, nil
+	return img, cleanup, err
 }
 
 func generateDirectorySource(fs afero.Fs, location string) (*Source, func(), error) {

syft/source/source_test.go

@@ -26,22 +26,34 @@ func TestParseInput(t *testing.T) {
 	tests := []struct {
 		name     string
 		input    string
+		platform string
 		expected Scheme
+		errFn    require.ErrorAssertionFunc
 	}{
 		{
 			name:     "ParseInput parses a file input",
 			input:    "test-fixtures/image-simple/file-1.txt",
 			expected: FileScheme,
 		},
+		{
+			name:     "errors out when using platform for non-image scheme",
+			input:    "test-fixtures/image-simple/file-1.txt",
+			platform: "arm64",
+			errFn:    require.Error,
+		},
 	}
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			sourceInput, err := ParseInput(test.input, true)
-			if err != nil {
-				t.Errorf("failed to ParseInput")
+			if test.errFn == nil {
+				test.errFn = require.NoError
+			}
+			sourceInput, err := ParseInput(test.input, test.platform, true)
+			test.errFn(t, err)
+			if test.expected != "" {
+				require.NotNil(t, sourceInput)
+				assert.Equal(t, sourceInput.Scheme, test.expected)
 			}
-			assert.Equal(t, sourceInput.Scheme, test.expected)
 		})
 	}
 }
@@ -452,7 +464,7 @@ func TestDirectoryExclusions(t *testing.T) {
 	registryOpts := &image.RegistryOptions{}
 	for _, test := range testCases {
 		t.Run(test.desc, func(t *testing.T) {
-			sourceInput, err := ParseInput("dir:"+test.input, false)
+			sourceInput, err := ParseInput("dir:"+test.input, "", false)
 			require.NoError(t, err)
 			src, fn, err := New(*sourceInput, registryOpts, test.exclusions)
 			defer fn()
@@ -546,7 +558,7 @@ func TestImageExclusions(t *testing.T) {
 	for _, test := range testCases {
 		t.Run(test.desc, func(t *testing.T) {
 			archiveLocation := imagetest.PrepareFixtureImage(t, "docker-archive", test.input)
-			sourceInput, err := ParseInput(archiveLocation, false)
+			sourceInput, err := ParseInput(archiveLocation, "", false)
 			require.NoError(t, err)
 			src, fn, err := New(*sourceInput, registryOpts, test.exclusions)
 			defer fn()