feat: push final image to cache repo

envbuilder.go

@@ -477,14 +477,19 @@ func Run(ctx context.Context, options Options) error {
 		if val, ok := os.LookupEnv("KANIKO_REGISTRY_MIRROR"); ok {
 			registryMirror = strings.Split(val, ";")
 		}
-		image, err := executor.DoBuild(&config.KanikoOptions{
+		var destinations []string
+		if options.CacheRepo != "" {
+			destinations = append(destinations, options.CacheRepo)
+		}
+		opts := &config.KanikoOptions{
 			// Boilerplate!
 			CustomPlatform:    platforms.Format(platforms.Normalize(platforms.DefaultSpec())),
 			SnapshotMode:      "redo",
 			RunV2:             true,
 			RunStdout:         stdoutWriter,
 			RunStderr:         stderrWriter,
-			Destinations:      []string{"local"},
+			Destinations:      destinations,
+			NoPush:            len(destinations) == 0,
 			CacheRunLayers:    true,
 			CacheCopyLayers:   true,
 			CompressedCaching: true,
@@ -515,11 +520,16 @@ func Run(ctx context.Context, options Options) error {
 				RegistryMirrors: registryMirror,
 			},
 			SrcContext: buildParams.BuildContext,
-		})
+		}
+		image, err := executor.DoBuild(opts)
 		if err != nil {
-			return nil, err
+			return nil, xerrors.Errorf("do build: %w", err)
+		}
+		if err := executor.DoPush(image, opts); err != nil {
+			return nil, xerrors.Errorf("do push: %w", err)
 		}
 		endStage("🏗️ Built image!")
+
 		return image, err
 	}
 

integration/integration_test.go

@@ -34,6 +34,8 @@ import (
 	"github.com/go-git/go-billy/v5/memfs"
 	"github.com/google/go-containerregistry/pkg/authn"
 	"github.com/google/go-containerregistry/pkg/name"
+	"github.com/google/go-containerregistry/pkg/registry"
+	"github.com/google/go-containerregistry/pkg/v1/remote"
 	"github.com/google/go-containerregistry/pkg/v1/remote/transport"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -987,6 +989,84 @@ COPY %s .`, testImageAlpine, inclFile)
 	}
 }
 
+func TestPushImage(t *testing.T) {
+	t.Parallel()
+
+	t.Run("Push", func(t *testing.T) {
+		t.Parallel()
+
+		srv := createGitServer(t, gitServerOptions{
+			files: map[string]string{
+				".devcontainer/Dockerfile": fmt.Sprintf("FROM %s\nRUN date --utc > /root/date.txt", testImageAlpine),
+				".devcontainer/devcontainer.json": `{
+				"name": "Test",
+				"build": {
+					"dockerfile": "Dockerfile"
+				},
+			}`,
+			},
+		})
+
+		// Given: an empty registry
+		testReg := setupInMemoryRegistry(t)
+		testRepo := testReg + "/test"
+		ref, err := name.ParseReference(testRepo + ":latest")
+		require.NoError(t, err)
+		_, err = remote.Image(ref)
+		require.ErrorContains(t, err, "NAME_UNKNOWN", "expected image to not be present before build + push")
+
+		// When: we run envbuilder with PUSH_IMAGE set
+		_, err = runEnvbuilder(t, options{env: []string{
+			envbuilderEnv("GIT_URL", srv.URL),
+			envbuilderEnv("CACHE_REPO", testRepo),
+		}})
+		require.NoError(t, err)
+
+		// Then: the image should be pushed
+		_, err = remote.Image(ref)
+		require.NoError(t, err, "expected image to be present after build + push")
+	})
+
+	t.Run("PushErr", func(t *testing.T) {
+		t.Parallel()
+
+		srv := createGitServer(t, gitServerOptions{
+			files: map[string]string{
+				".devcontainer/Dockerfile": fmt.Sprintf("FROM %s\nRUN date --utc > /root/date.txt", testImageAlpine),
+				".devcontainer/devcontainer.json": `{
+				"name": "Test",
+				"build": {
+					"dockerfile": "Dockerfile"
+				},
+			}`,
+			},
+		})
+
+		// Given: registry is not set up (in this case, not a registry)
+		notRegSrv := httptest.NewServer(http.NotFoundHandler())
+		notRegURL := strings.TrimPrefix(notRegSrv.URL, "http://") + "/test"
+
+		// When: we run envbuilder with PUSH_IMAGE set
+		_, err := runEnvbuilder(t, options{env: []string{
+			envbuilderEnv("GIT_URL", srv.URL),
+			envbuilderEnv("CACHE_REPO", notRegURL),
+		}})
+		// Then: should fail with a descriptive error
+		require.ErrorContains(t, err, "unexpected status code 404 Not Found")
+	})
+}
+
+func setupInMemoryRegistry(t *testing.T) string {
+	t.Helper()
+	tempDir := t.TempDir()
+	testReg := registry.New(registry.WithBlobHandler(registry.NewDiskBlobHandler(tempDir)))
+	regSrv := httptest.NewServer(testReg)
+	t.Cleanup(func() { regSrv.Close() })
+	regSrvURL, err := url.Parse(regSrv.URL)
+	require.NoError(t, err)
+	return fmt.Sprintf("localhost:%s", regSrvURL.Port())
+}
+
 // TestMain runs before all tests to build the envbuilder image.
 func TestMain(m *testing.M) {
 	checkTestRegistry()