add http head based digest comparison to avoid dockerhub rate limits

pkg/registry/manifest/manifest.go

@@ -0,0 +1,64 @@
+package manifest
+
+import (
+	"fmt"
+	"github.com/containrrr/watchtower/pkg/registry/helpers"
+	"github.com/containrrr/watchtower/pkg/types"
+	ref "github.com/docker/distribution/reference"
+	"github.com/sirupsen/logrus"
+	url2 "net/url"
+	"strings"
+)
+
+// BuildManifestURL from raw image data
+func BuildManifestURL(container types.Container) (string, error) {
+
+	normalizedName, err := ref.ParseNormalizedNamed(container.ImageName())
+	if err != nil {
+		return "", err
+	}
+
+	host, err := helpers.NormalizeRegistry(normalizedName.String())
+	img, tag := extractImageAndTag(strings.TrimPrefix(container.ImageName(), host+"/"))
+
+	logrus.WithFields(logrus.Fields{
+		"image":      img,
+		"tag":        tag,
+		"normalized": normalizedName,
+		"host":       host,
+	}).Debug("Parsing image ref")
+
+	if err != nil {
+		return "", err
+	}
+	img = strings.TrimPrefix(img, fmt.Sprintf("%s/", host))
+	if !strings.Contains(img, "/") {
+		img = "library/" + img
+	}
+	url := url2.URL{
+		Scheme: "https",
+		Host:   host,
+		Path:   fmt.Sprintf("/v2/%s/manifests/%s", img, tag),
+	}
+	return url.String(), nil
+}
+
+func extractImageAndTag(imageName string) (string, string) {
+	var img string
+	var tag string
+
+	if strings.Contains(imageName, ":") {
+		parts := strings.Split(imageName, ":")
+		if len(parts) > 2 {
+			img = fmt.Sprintf("%s%s", parts[0], parts[1])
+			tag = parts[3]
+		} else {
+			img = parts[0]
+			tag = parts[1]
+		}
+	} else {
+		img = imageName
+		tag = "latest"
+	}
+	return img, tag
+}

pkg/registry/manifest/manifest_test.go

@@ -0,0 +1,66 @@
+package manifest_test
+
+import (
+	"github.com/containrrr/watchtower/internal/actions/mocks"
+	"github.com/containrrr/watchtower/pkg/registry/manifest"
+	apiTypes "github.com/docker/docker/api/types"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	"testing"
+	"time"
+)
+
+func TestManifest(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Manifest Suite")
+}
+
+var _ = Describe("the manifest module", func() {
+	mockId := "mock-id"
+	mockName := "mock-container"
+	mockCreated := time.Now()
+
+	When("building a manifest url", func() {
+		It("should return a valid url given a fully qualified image", func() {
+			expected := "https://ghcr.io/v2/containrrr/watchtower/manifests/latest"
+			imageInfo := apiTypes.ImageInspect{
+				RepoTags: []string{
+					"ghcr.io/k6io/operator:latest",
+				},
+			}
+			mock := mocks.CreateMockContainerWithImageInfo(mockId, mockName, "ghcr.io/containrrr/watchtower:latest", mockCreated, imageInfo)
+			res, err := manifest.BuildManifestURL(mock)
+			Expect(err).NotTo(HaveOccurred())
+			Expect(res).To(Equal(expected))
+		})
+		It("should assume dockerhub for non-qualified images", func() {
+			expected := "https://index.docker.io/v2/containrrr/watchtower/manifests/latest"
+			imageInfo := apiTypes.ImageInspect{
+				RepoTags: []string{
+					"containrrr/watchtower:latest",
+				},
+			}
+
+			mock := mocks.CreateMockContainerWithImageInfo(mockId, mockName, "containrrr/watchtower:latest", mockCreated, imageInfo)
+			res, err := manifest.BuildManifestURL(mock)
+			Expect(err).NotTo(HaveOccurred())
+			Expect(res).To(Equal(expected))
+		})
+		It("should assume latest for images that lack an explicit tag", func() {
+			expected := "https://index.docker.io/v2/containrrr/watchtower/manifests/latest"
+			imageInfo := apiTypes.ImageInspect{
+
+				RepoTags: []string{
+					"containrrr/watchtower",
+				},
+			}
+
+			mock := mocks.CreateMockContainerWithImageInfo(mockId, mockName, "containrrr/watchtower", mockCreated, imageInfo)
+
+			res, err := manifest.BuildManifestURL(mock)
+			Expect(err).NotTo(HaveOccurred())
+			Expect(res).To(Equal(expected))
+		})
+	})
+
+})