osbuild: add support for the org.osbuild.skopeo source

Add bindings for the `org.osbuild.skopeo` source that can be used
to fetch container images from container registires.

internal/osbuild/skopeo_source.go

@@ -0,0 +1,73 @@
+package osbuild
+
+import (
+	"fmt"
+	"regexp"
+)
+
+var skopeoDigestPattern = regexp.MustCompile(`sha256:[0-9a-f]{64}`)
+
+type SkopeoSource struct {
+	Items map[string]SkopeoSourceItem `json:"items"`
+}
+
+func (SkopeoSource) isSource() {}
+
+type SkopeopSourceImage struct {
+	Name      string `json:"name"`
+	Digest    string `json:"digest"`
+	TLSVerify *bool  `json:"tls-verify,omitempty"`
+}
+
+type SkopeoSourceItem struct {
+	Image SkopeopSourceImage `json:"image"`
+}
+
+// NewSkopeoSourceItem creates a new source item for name and digest
+func NewSkopeoSourceItem(name, digest string, tlsVerify *bool) SkopeoSourceItem {
+	item := SkopeoSourceItem{
+		Image: SkopeopSourceImage{
+			Name:      name,
+			Digest:    digest,
+			TLSVerify: tlsVerify,
+		},
+	}
+
+	return item
+}
+
+func (item SkopeoSourceItem) validate() error {
+
+	if item.Image.Name == "" {
+		return fmt.Errorf("source item has empty name")
+	}
+
+	if !skopeoDigestPattern.MatchString(item.Image.Digest) {
+		return fmt.Errorf("source item has invalid digest")
+	}
+
+	return nil
+}
+
+// NewSkopeoSource creates a new and empty SkopeoSource
+func NewSkopeoSource() *SkopeoSource {
+	return &SkopeoSource{
+		Items: make(map[string]SkopeoSourceItem),
+	}
+}
+
+// AddItem adds a source item to the source; will panic
+// if any of the supplied options are invalid or missing
+func (source *SkopeoSource) AddItem(name, digest, image string, tlsVerify *bool) {
+	item := NewSkopeoSourceItem(name, digest, tlsVerify)
+
+	if err := item.validate(); err != nil {
+		panic(err)
+	}
+
+	if !skopeoDigestPattern.MatchString(image) {
+		panic("item has invalid image id")
+	}
+
+	source.Items[image] = item
+}

internal/osbuild/skopeo_source_test.go

@@ -0,0 +1,58 @@
+package osbuild
+
+import (
+	"testing"
+
+	"github.com/osbuild/osbuild-composer/internal/common"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewSkopeoSource(t *testing.T) {
+	testDigest := "sha256:f29b6cd42a94a574583439addcd6694e6224f0e4b32044c9e3aee4c4856c2a50"
+	imageID := "sha256:c2ecf25cf190e76b12b07436ad5140d4ba53d8a136d498705e57a006837a720f"
+
+	source := NewSkopeoSource()
+
+	source.AddItem("name", testDigest, imageID, common.BoolToPtr(false))
+	assert.Len(t, source.Items, 1)
+
+	item, ok := source.Items[imageID]
+	assert.True(t, ok)
+	assert.Equal(t, item.Image.Name, "name")
+	assert.Equal(t, item.Image.Digest, testDigest)
+	assert.Equal(t, item.Image.TLSVerify, common.BoolToPtr(false))
+
+	testDigest = "sha256:d49eebefb6c7ce5505594bef652bd4adc36f413861bd44209d9b9486310b1264"
+	imageID = "sha256:d2ab8fea7f08a22f03b30c13c6ea443121f25e87202a7496e93736efa6fe345a"
+
+	source.AddItem("name2", testDigest, imageID, nil)
+	assert.Len(t, source.Items, 2)
+	item, ok = source.Items[imageID]
+	assert.True(t, ok)
+	assert.Nil(t, item.Image.TLSVerify)
+
+	// empty name
+	assert.Panics(t, func() {
+		source.AddItem("", testDigest, imageID, nil)
+	})
+
+	// empty digest
+	assert.Panics(t, func() {
+		source.AddItem("name", "", imageID, nil)
+	})
+
+	// empty image id
+	assert.Panics(t, func() {
+		source.AddItem("name", testDigest, "", nil)
+	})
+
+	// invalid digest
+	assert.Panics(t, func() {
+		source.AddItem("name", "foo", imageID, nil)
+	})
+
+	// invalid image id
+	assert.Panics(t, func() {
+		source.AddItem("name", testDigest, "sha256:foo", nil)
+	})
+}