add http head based digest comparison to avoid dockerhub rate limits

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))
+		})
+	})
+
+})