Merge a3fc5a92e4 into d13dec297a

cmd/flux/diff_artifact.go

@@ -17,24 +17,48 @@ limitations under the License.
 package main
 
 import (
+	"bytes"
 	"context"
+	"errors"
 	"fmt"
+	"io"
+	"io/fs"
 	"os"
+	"os/exec"
+	"path/filepath"
+	"sort"
+	"strings"
 
+	"bitbucket.org/creachadair/stringset"
 	oci "github.com/fluxcd/pkg/oci/client"
+	"github.com/fluxcd/pkg/tar"
 	sourcev1 "github.com/fluxcd/source-controller/api/v1beta2"
+	"github.com/go-git/go-git/v5/plumbing/format/gitignore"
+	"github.com/gonvenience/ytbx"
+	"github.com/google/shlex"
+	"github.com/hexops/gotextdiff"
+	"github.com/hexops/gotextdiff/myers"
+	"github.com/hexops/gotextdiff/span"
+	"github.com/homeport/dyff/pkg/dyff"
 	"github.com/spf13/cobra"
+	"golang.org/x/exp/maps"
 
 	"github.com/fluxcd/flux2/v2/internal/flags"
+	"github.com/fluxcd/flux2/v2/pkg/printers"
 )
 
+var ErrDiffArtifactChanged = errors.New("the artifact contents differ")
+
 var diffArtifactCmd = &cobra.Command{
-	Use:   "artifact",
+	Use:   "artifact <from> <to>",
 	Short: "Diff Artifact",
-	Long:  withPreviewNote(`The diff artifact command computes the diff between the remote OCI artifact and a local directory or file`),
+	Long: withPreviewNote(fmt.Sprintf(
+		"The diff artifact command prints the diff between the remote OCI artifact and a local directory or file.\n\n"+
+			"You can overwrite the command used for diffing by setting the %q environment variable.", externalDiffVar)),
 	Example: `# Check if local files differ from remote
-flux diff artifact oci://ghcr.io/stefanprodan/manifests:podinfo:6.2.0 --path=./kustomize`,
+flux diff artifact oci://ghcr.io/stefanprodan/manifests:podinfo:6.2.0 ./kustomize`,
 	RunE: diffArtifactCmdRun,
+	Args: cobra.RangeArgs(1, 2),
 }
 
 type diffArtifactFlags struct {
@@ -42,6 +66,8 @@ type diffArtifactFlags struct {
 	creds       string
 	provider    flags.SourceOCIProvider
 	ignorePaths []string
+	brief       bool
+	differ      *differFlag
 }
 
 var diffArtifactArgs = newDiffArtifactArgs()
@@ -49,34 +75,58 @@ var diffArtifactArgs = newDiffArtifactArgs()
 func newDiffArtifactArgs() diffArtifactFlags {
 	return diffArtifactFlags{
 		provider: flags.SourceOCIProvider(sourcev1.GenericOCIProvider),
+
+		differ: &differFlag{
+			options: map[string]differ{
+				"dyff": dyffBuiltin{
+					opts: []dyff.CompareOption{
+						dyff.IgnoreOrderChanges(false),
+						dyff.KubernetesEntityDetection(true),
+					},
+				},
+				"external": externalDiff{},
+				"unified":  unifiedDiff{},
+			},
+			description: map[string]string{
+				"dyff":     `semantic diff for YAML inputs`,
+				"external": `execute the command in the "` + externalDiffVar + `" environment variable`,
+				"unified":  "generic unified diff for arbitrary text inputs",
+			},
+			value:  "unified",
+			differ: unifiedDiff{},
+		},
 	}
 }
 
 func init() {
-	diffArtifactCmd.Flags().StringVar(&diffArtifactArgs.path, "path", "", "path to the directory where the Kubernetes manifests are located")
+	diffArtifactCmd.Flags().StringVar(&diffArtifactArgs.path, "path", "", "path to the directory or file containing the Kubernetes manifests (deprecated, use a second positional argument instead)")
 	diffArtifactCmd.Flags().StringVar(&diffArtifactArgs.creds, "creds", "", "credentials for OCI registry in the format <username>[:<password>] if --provider is generic")
 	diffArtifactCmd.Flags().Var(&diffArtifactArgs.provider, "provider", sourceOCIRepositoryArgs.provider.Description())
 	diffArtifactCmd.Flags().StringSliceVar(&diffArtifactArgs.ignorePaths, "ignore-paths", excludeOCI, "set paths to ignore in .gitignore format")
+	diffArtifactCmd.Flags().BoolVarP(&diffArtifactArgs.brief, "brief", "q", false, "just print a line when the resources differ; does not output a list of changes")
+	diffArtifactCmd.Flags().Var(diffArtifactArgs.differ, "differ", diffArtifactArgs.differ.usage())
+
 	diffCmd.AddCommand(diffArtifactCmd)
 }
 
 func diffArtifactCmdRun(cmd *cobra.Command, args []string) error {
+	var from, to string
+
 	if len(args) < 1 {
 		return fmt.Errorf("artifact URL is required")
 	}
-	ociURL := args[0]
+	from = args[0]
 
-	if diffArtifactArgs.path == "" {
+	switch {
-		return fmt.Errorf("invalid path %q", diffArtifactArgs.path)
+	case len(args) >= 2:
-	}
+		to = args[1]
 
-	url, err := oci.ParseArtifactURL(ociURL)
+	case diffArtifactArgs.path != "":
-	if err != nil {
+		// for backwards compatibility
-		return err
+		to = diffArtifactArgs.path
-	}
 
-	if _, err := os.Stat(diffArtifactArgs.path); err != nil {
+	default:
-		return fmt.Errorf("invalid path '%s', must point to an existing directory or file", diffArtifactArgs.path)
+		return errors.New("a second artifact is required")
 	}
 
 	ctx, cancel := context.WithTimeout(context.Background(), rootArgs.timeout)
@@ -98,15 +148,402 @@ func diffArtifactCmdRun(cmd *cobra.Command, args []string) error {
 			return fmt.Errorf("provider not supported: %w", err)
 		}
 
-		if err := ociClient.LoginWithProvider(ctx, url, ociProvider); err != nil {
+		if url, err := oci.ParseArtifactURL(from); err == nil {
-			return fmt.Errorf("error during login with provider: %w", err)
+			if err := ociClient.LoginWithProvider(ctx, url, ociProvider); err != nil {
+				return fmt.Errorf("error during login with provider: %w", err)
+			}
+		}
+
+		if url, err := oci.ParseArtifactURL(to); err == nil {
+			if err := ociClient.LoginWithProvider(ctx, url, ociProvider); err != nil {
+				return fmt.Errorf("error during login with provider: %w", err)
+			}
 		}
 	}
 
-	if err := ociClient.Diff(ctx, url, diffArtifactArgs.path, diffArtifactArgs.ignorePaths); err != nil {
+	diff, err := diffArtifact(ctx, ociClient, from, to, diffArtifactArgs)
+	if err != nil {
 		return err
 	}
 
-	logger.Successf("no changes detected")
+	if diff == "" {
+		logger.Successf("no changes detected")
+		return nil
+	}
+
+	if !diffArtifactArgs.brief {
+		cmd.Print(diff)
+	}
+
+	return fmt.Errorf("%q and %q: %w", from, to, ErrDiffArtifactChanged)
+}
+
+func newMatcher(ignorePaths []string) gitignore.Matcher {
+	var patterns []gitignore.Pattern
+
+	for _, path := range ignorePaths {
+		patterns = append(patterns, gitignore.ParsePattern(path, nil))
+	}
+
+	return gitignore.NewMatcher(patterns)
+}
+
+func diffArtifact(ctx context.Context, client *oci.Client, from, to string, flags diffArtifactFlags) (string, error) {
+	fromDir, fromCleanup, err := loadArtifact(ctx, client, from)
+	if err != nil {
+		return "", err
+	}
+	defer fromCleanup()
+
+	toDir, toCleanup, err := loadArtifact(ctx, client, to)
+	if err != nil {
+		return "", err
+	}
+	defer toCleanup()
+
+	return flags.differ.Diff(ctx, fromDir, toDir, flags.ignorePaths)
+}
+
+// loadArtifact ensures that the artifact is in a local directory that can be
+// recursively diffed. If necessary, files are downloaded, extracted, and/or
+// copied into temporary directories for this purpose.
+func loadArtifact(ctx context.Context, client *oci.Client, path string) (dir string, cleanup func(), err error) {
+	fi, err := os.Stat(path)
+	if err == nil && fi.IsDir() {
+		return path, func() {}, nil
+	}
+
+	if err == nil && fi.Mode().IsRegular() {
+		return loadArtifactFile(path)
+	}
+
+	url, err := oci.ParseArtifactURL(path)
+	if err == nil {
+		return loadArtifactOCI(ctx, client, url)
+	}
+
+	return "", nil, fmt.Errorf("%q: %w", path, os.ErrNotExist)
+}
+
+// loadArtifactOCI pulls the remove artifact into a temporary directory.
+func loadArtifactOCI(ctx context.Context, client *oci.Client, url string) (dir string, cleanup func(), err error) {
+	tmpDir, err := os.MkdirTemp("", "flux-diff-artifact")
+	if err != nil {
+		return "", nil, fmt.Errorf("could not create temporary directory: %w", err)
+	}
+
+	cleanup = func() {
+		if err := os.RemoveAll(tmpDir); err != nil {
+			fmt.Fprintf(os.Stderr, "os.RemoveAll(%q): %v\n", tmpDir, err)
+		}
+	}
+
+	if _, err := client.Pull(ctx, url, tmpDir); err != nil {
+		cleanup()
+		return "", nil, fmt.Errorf("Pull(%q): %w", url, err)
+	}
+
+	return tmpDir, cleanup, nil
+}
+
+// loadArtifactFile copies a file into a temporary directory to allow for recursive diffing.
+// If path is a .tar.gz or .tgz file, the archive is extracted into a temporary directory.
+// Otherwise the file is copied verbatim.
+func loadArtifactFile(path string) (dir string, cleanup func(), err error) {
+	tmpDir, err := os.MkdirTemp("", "flux-diff-artifact")
+	if err != nil {
+		return "", nil, fmt.Errorf("could not create temporary directory: %w", err)
+	}
+
+	cleanup = func() {
+		if err := os.RemoveAll(tmpDir); err != nil {
+			fmt.Fprintf(os.Stderr, "os.RemoveAll(%q): %v\n", tmpDir, err)
+		}
+	}
+
+	if strings.HasSuffix(path, ".tar.gz") || strings.HasSuffix(path, ".tgz") {
+		if err := extractTo(path, tmpDir); err != nil {
+			cleanup()
+			return "", nil, err
+		}
+	} else {
+		fh, err := os.Open(path)
+		if err != nil {
+			cleanup()
+			return "", nil, fmt.Errorf("os.Open(%q): %w", path, err)
+		}
+		defer fh.Close()
+
+		name := filepath.Join(tmpDir, filepath.Base(path))
+		if err := copyFile(fh, name); err != nil {
+			cleanup()
+			return "", nil, fmt.Errorf("os.Open(%q): %w", path, err)
+		}
+	}
+
+	return tmpDir, cleanup, nil
+}
+
+// extractTo extracts the .tar.gz / .tgz archive at archivePath into the destDir directory.
+func extractTo(archivePath, destDir string) error {
+	archiveFH, err := os.Open(archivePath)
+	if err != nil {
+		return err
+	}
+	defer archiveFH.Close()
+
+	if err := tar.Untar(archiveFH, destDir); err != nil {
+		return fmt.Errorf("Untar(%q, %q): %w", archivePath, destDir, err)
+	}
+
 	return nil
 }
+
+func copyFile(from io.Reader, to string) error {
+	fh, err := os.Create(to)
+	if err != nil {
+		return fmt.Errorf("os.Create(%q): %w", to, err)
+	}
+	defer fh.Close()
+
+	if _, err := io.Copy(fh, from); err != nil {
+		return fmt.Errorf("io.Copy(%q): %w", to, err)
+	}
+
+	return nil
+}
+
+type differ interface {
+	// Diff compares the two local directories "to" and "from" and returns their differences, or an empty string if they are equal.
+	Diff(ctx context.Context, from, to string, ignorePaths []string) (string, error)
+}
+
+type unifiedDiff struct{}
+
+func (d unifiedDiff) Diff(_ context.Context, fromDir, toDir string, ignorePaths []string) (string, error) {
+	matcher := newMatcher(ignorePaths)
+
+	fromFiles, err := filesInDir(fromDir, matcher)
+	if err != nil {
+		return "", err
+	}
+	fmt.Fprintf(os.Stderr, "fromFiles = %v\n", fromFiles)
+
+	toFiles, err := filesInDir(toDir, matcher)
+	if err != nil {
+		return "", err
+	}
+	fmt.Fprintf(os.Stderr, "toFiles = %v\n", toFiles)
+
+	allFiles := fromFiles.Union(toFiles)
+
+	var sb strings.Builder
+
+	for _, relPath := range allFiles.Elements() {
+		diff, err := d.diffFiles(fromDir, toDir, relPath)
+		if err != nil {
+			return "", err
+		}
+
+		fmt.Fprint(&sb, diff)
+	}
+
+	return sb.String(), nil
+}
+
+func (d unifiedDiff) diffFiles(fromDir, toDir, relPath string) (string, error) {
+	fromPath := filepath.Join(fromDir, relPath)
+	fromData, err := d.readFile(fromPath)
+	switch {
+	case errors.Is(err, fs.ErrNotExist):
+		return fmt.Sprintf("Only in %s: %s\n", toDir, relPath), nil
+	case err != nil:
+		return "", fmt.Errorf("readFile(%q): %w", fromPath, err)
+	}
+
+	toPath := filepath.Join(toDir, relPath)
+	toData, err := d.readFile(toPath)
+	switch {
+	case errors.Is(err, fs.ErrNotExist):
+		return fmt.Sprintf("Only in %s: %s\n", fromDir, relPath), nil
+	case err != nil:
+		return "", fmt.Errorf("readFile(%q): %w", toPath, err)
+	}
+
+	edits := myers.ComputeEdits(span.URIFromPath(fromPath), string(fromData), string(toData))
+	return fmt.Sprint(gotextdiff.ToUnified(fromPath, toPath, string(fromData), edits)), nil
+}
+
+func (d unifiedDiff) readFile(path string) ([]byte, error) {
+	file, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	return io.ReadAll(file)
+}
+
+func splitPath(path string) []string {
+	return strings.Split(path, string([]rune{filepath.Separator}))
+}
+
+func filesInDir(root string, matcher gitignore.Matcher) (stringset.Set, error) {
+	var files stringset.Set
+
+	err := filepath.WalkDir(root, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+
+		relPath, err := filepath.Rel(root, path)
+		if err != nil {
+			return fmt.Errorf("filepath.Rel(%q, %q): %w", root, path, err)
+		}
+
+		if matcher.Match(splitPath(relPath), d.IsDir()) {
+			if d.IsDir() {
+				return fs.SkipDir
+			}
+			return nil
+		}
+
+		if !d.Type().IsRegular() {
+			return nil
+		}
+
+		files.Add(relPath)
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return files, err
+}
+
+// externalDiff implements the differ interface using an external diff command.
+type externalDiff struct{}
+
+// externalDiffVar is the environment variable users can use to overwrite the external diff command.
+const externalDiffVar = "FLUX_EXTERNAL_DIFF"
+
+func (externalDiff) Diff(ctx context.Context, fromDir, toDir string, ignorePaths []string) (string, error) {
+	cmdline := os.Getenv(externalDiffVar)
+	if cmdline == "" {
+		return "", fmt.Errorf("the required %q environment variable is unset", externalDiffVar)
+	}
+
+	args, err := shlex.Split(cmdline)
+	if err != nil {
+		return "", fmt.Errorf("shlex.Split(%q): %w", cmdline, err)
+	}
+
+	var executable string
+	executable, args = args[0], args[1:]
+
+	for _, path := range ignorePaths {
+		args = append(args, "--exclude", path)
+	}
+
+	args = append(args, fromDir, toDir)
+
+	cmd := exec.CommandContext(ctx, executable, args...)
+
+	var stdout bytes.Buffer
+
+	cmd.Stdout = &stdout
+	cmd.Stderr = os.Stderr
+
+	err = cmd.Run()
+
+	var exitErr *exec.ExitError
+	if errors.As(err, &exitErr) && exitErr.ExitCode() == 1 {
+		// exit code 1 only means there was a difference => ignore
+	} else if err != nil {
+		return "", fmt.Errorf("executing %q: %w", executable, err)
+	}
+
+	return stdout.String(), nil
+}
+
+// dyffBuiltin implements the differ interface using `dyff`, a semantic diff for YAML documents.
+type dyffBuiltin struct {
+	opts []dyff.CompareOption
+}
+
+func (d dyffBuiltin) Diff(ctx context.Context, fromDir, toDir string, _ []string) (string, error) {
+	fromFile, err := ytbx.LoadDirectory(fromDir)
+	if err != nil {
+		return "", fmt.Errorf("ytbx.LoadDirectory(%q): %w", fromDir, err)
+	}
+
+	toFile, err := ytbx.LoadDirectory(toDir)
+	if err != nil {
+		return "", fmt.Errorf("ytbx.LoadDirectory(%q): %w", toDir, err)
+	}
+
+	report, err := dyff.CompareInputFiles(fromFile, toFile, d.opts...)
+	if err != nil {
+		return "", fmt.Errorf("dyff.CompareInputFiles(): %w", err)
+	}
+
+	if len(report.Diffs) == 0 {
+		return "", nil
+	}
+
+	var buf bytes.Buffer
+
+	if err := printers.NewDyffPrinter().Print(&buf, report); err != nil {
+		return "", fmt.Errorf("formatting dyff report: %w", err)
+	}
+
+	return buf.String(), nil
+}
+
+// differFlag implements pflag.Value for choosing a diffing implementation.
+type differFlag struct {
+	options     map[string]differ
+	description map[string]string
+	value       string
+	differ
+}
+
+func (f *differFlag) Set(s string) error {
+	d, ok := f.options[s]
+	if !ok {
+		return fmt.Errorf("invalid value: %q", s)
+	}
+
+	f.value = s
+	f.differ = d
+
+	return nil
+}
+
+func (f *differFlag) String() string {
+	return f.value
+}
+
+func (f *differFlag) Type() string {
+	keys := maps.Keys(f.options)
+
+	sort.Strings(keys)
+
+	return strings.Join(keys, "|")
+}
+
+func (f *differFlag) usage() string {
+	var b strings.Builder
+	fmt.Fprint(&b, "how the diff is generated:")
+
+	keys := maps.Keys(f.options)
+
+	sort.Strings(keys)
+
+	for _, key := range keys {
+		fmt.Fprintf(&b, "\n  %q: %s", key, f.description[key])
+	}
+
+	return b.String()
+}

cmd/flux/diff_artifact_test.go

@@ -22,6 +22,9 @@ package main
 import (
 	"context"
 	"fmt"
+	"io"
+	"os"
+	"path/filepath"
 	"testing"
 	"time"
 
@@ -65,6 +68,7 @@ func TestDiffArtifact(t *testing.T) {
 		argsTpl  string
 		pushFile string
 		diffFile string
+		diffName string
 		assert   assertFunc
 	}{
 		{
@@ -75,14 +79,50 @@ func TestDiffArtifact(t *testing.T) {
 			diffFile: "./testdata/diff-artifact/deployment.yaml",
 			assert:   assertGoldenFile("testdata/diff-artifact/success.golden"),
 		},
+		{
+			name:     "create unified diff output by default",
+			url:      "oci://%s/podinfo:2.0.0",
+			argsTpl:  "diff artifact %s --path=%s",
+			pushFile: "./testdata/diff-artifact/deployment.yaml",
+			diffFile: "./testdata/diff-artifact/deployment-diff.yaml",
+			diffName: "deployment.yaml",
+			assert: assert(
+				assertErrorIs(ErrDiffArtifactChanged),
+				assertRegexp(`(?m)^-            cpu: 1000m$`),
+				assertRegexp(`(?m)^\+            cpu: 2000m$`),
+			),
+		},
 		{
 			name:     "should fail if there is a diff",
 			url:      "oci://%s/podinfo:2.0.0",
 			argsTpl:  "diff artifact %s --path=%s",
 			pushFile: "./testdata/diff-artifact/deployment.yaml",
 			diffFile: "./testdata/diff-artifact/deployment-diff.yaml",
-			assert:   assertError("the remote artifact contents differs from the local one"),
+			diffName: "only-local.yaml",
+			assert: assert(
+				assertErrorIs(ErrDiffArtifactChanged),
+				assertRegexp(`(?m)^Only in [^:]+: deployment.yaml$`),
+				assertRegexp(`(?m)^Only in [^:]+: only-local.yaml$`),
+			),
 		},
+		{
+			name:     "semantic diff using dyff",
+			url:      "oci://%s/podinfo:2.0.0",
+			argsTpl:  "diff artifact %s --path=%s --differ=dyff",
+			pushFile: "./testdata/diff-artifact/deployment.yaml",
+			diffFile: "./testdata/diff-artifact/deployment-diff.yaml",
+			diffName: "deployment.yaml",
+			assert: assert(
+				assertErrorIs(ErrDiffArtifactChanged),
+				assertRegexp(`(?m)^spec.template.spec.containers.podinfod.resources.limits.cpu$`),
+				assertRegexp(`(?m)^  ± value change$`),
+				assertRegexp(`(?m)^    - 1000m$`),
+				assertRegexp(`(?m)^    \+ 2000m$`),
+			),
+		},
+		// Attention: tests do not spawn a new process when executing commands.
+		// That means that the --differ flag remains set to "dyff" for
+		// subsequent tests.
 	}
 
 	ctx := ctrl.SetupSignalHandler()
@@ -99,11 +139,38 @@ func TestDiffArtifact(t *testing.T) {
 				t.Fatalf(fmt.Errorf("failed to push image: %w", err).Error())
 			}
 
+			diffFile := tt.diffFile
+			if tt.diffName != "" {
+				diffFile = makeTempFile(t, tt.diffFile, tt.diffName)
+			}
+
 			cmd := cmdTestCase{
-				args:   fmt.Sprintf(tt.argsTpl, tt.url, tt.diffFile),
+				args:   fmt.Sprintf(tt.argsTpl, tt.url, diffFile),
 				assert: tt.assert,
 			}
 			cmd.runTestCmd(t)
 		})
 	}
 }
+
+func makeTempFile(t *testing.T, source, basename string) string {
+	path := filepath.Join(t.TempDir(), basename)
+	out, err := os.Create(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer out.Close()
+
+	in, err := os.Open(source)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer in.Close()
+
+	_, err = io.Copy(out, in)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	return path
+}

cmd/flux/main_test.go

@@ -20,11 +20,13 @@ import (
 	"bufio"
 	"bytes"
 	"context"
+	"errors"
 	"flag"
 	"fmt"
 	"io"
 	"os"
 	"path/filepath"
+	"regexp"
 	"strings"
 	"sync/atomic"
 	"testing"
@@ -33,7 +35,7 @@ import (
 
 	"github.com/google/go-cmp/cmp"
 	"github.com/mattn/go-shellwords"
-	"k8s.io/apimachinery/pkg/api/errors"
+	k8serrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	k8syaml "k8s.io/apimachinery/pkg/util/yaml"
 	"k8s.io/client-go/tools/clientcmd"
@@ -115,7 +117,7 @@ func (m *testEnvKubeManager) CreateObjects(clientObjects []*unstructured.Unstruc
 		obj.SetResourceVersion(createObj.GetResourceVersion())
 		err = m.client.Status().Update(context.Background(), obj)
 		// Updating status of static objects results in not found error.
-		if err != nil && !errors.IsNotFound(err) {
+		if err != nil && !k8serrors.IsNotFound(err) {
 			return err
 		}
 	}
@@ -272,6 +274,15 @@ func assertError(expected string) assertFunc {
 	}
 }
 
+func assertErrorIs(want error) assertFunc {
+	return func(_ string, got error) error {
+		if errors.Is(got, want) {
+			return nil
+		}
+		return fmt.Errorf("Expected error '%v' but got '%v'", want, got)
+	}
+}
+
 // Expect the command to succeed with the expected test output.
 func assertGoldenValue(expected string) assertFunc {
 	return assert(
@@ -328,6 +339,17 @@ func assertGoldenTemplateFile(goldenFile string, templateValues map[string]strin
 		})
 }
 
+func assertRegexp(expected string) assertFunc {
+	re := regexp.MustCompile(expected)
+
+	return func(output string, _ error) error {
+		if !re.MatchString(output) {
+			return fmt.Errorf("Output does not match regular expression:\nOutput:\n%s\n\nRegular expression:\n%s", output, expected)
+		}
+		return nil
+	}
+}
+
 type TestClusterMode int
 
 const (

cmd/flux/testdata/diff-artifact/deployment-diff.yaml

@@ -4,7 +4,7 @@ metadata:
   labels:
       kustomize.toolkit.fluxcd.io/name: podinfo
       kustomize.toolkit.fluxcd.io/namespace: {{ .fluxns }}
-  name: podinfo-diff
+  name: podinfo
   namespace: default
 spec:
   minReadySeconds: 3

cmd/flux/testdata/diff-artifact/deployment.yaml

@@ -71,7 +71,7 @@ spec:
           timeoutSeconds: 5
         resources:
           limits:
-            cpu: 2000m
+            cpu: 1000m
             memory: 512Mi
           requests:
             cpu: 100m

go.mod

@@ -6,6 +6,7 @@ go 1.22.4
 replace gopkg.in/yaml.v3 => gopkg.in/yaml.v3 v3.0.1
 
 require (
+	bitbucket.org/creachadair/stringset v0.0.14
 	github.com/Masterminds/semver/v3 v3.2.1
 	github.com/ProtonMail/go-crypto v1.0.0
 	github.com/cyphar/filepath-securejoin v0.3.1
@@ -37,6 +38,7 @@ require (
 	github.com/gonvenience/ytbx v1.4.4
 	github.com/google/go-cmp v0.6.0
 	github.com/google/go-containerregistry v0.20.2
+	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510
 	github.com/hashicorp/go-cleanhttp v0.5.2
 	github.com/homeport/dyff v1.7.1
 	github.com/lucasb-eyer/go-colorful v1.2.0
@@ -50,6 +52,7 @@ require (
 	github.com/spf13/pflag v1.0.5
 	github.com/theckman/yacspin v0.13.12
 	golang.org/x/crypto v0.26.0
+	golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56
 	golang.org/x/term v0.23.0
 	golang.org/x/text v0.17.0
 	k8s.io/api v0.31.0
@@ -144,7 +147,6 @@ require (
 	github.com/google/go-github/v64 v64.0.0 // indirect
 	github.com/google/go-querystring v1.1.0 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
-	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/gorilla/handlers v1.5.2 // indirect
 	github.com/gorilla/mux v1.8.1 // indirect
@@ -157,6 +159,7 @@ require (
 	github.com/hashicorp/go-version v1.7.0 // indirect
 	github.com/hashicorp/golang-lru/arc/v2 v2.0.5 // indirect
 	github.com/hashicorp/golang-lru/v2 v2.0.5 // indirect
+	github.com/hexops/gotextdiff v1.0.3
 	github.com/imdario/mergo v0.3.16 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99 // indirect
@@ -232,7 +235,6 @@ require (
 	go.opentelemetry.io/otel/trace v1.28.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.3.1 // indirect
 	go.starlark.net v0.0.0-20231121155337-90ade8b19d09 // indirect
-	golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56 // indirect
 	golang.org/x/net v0.28.0 // indirect
 	golang.org/x/oauth2 v0.22.0 // indirect
 	golang.org/x/sync v0.8.0 // indirect

go.sum

@@ -1,3 +1,5 @@
+bitbucket.org/creachadair/stringset v0.0.14 h1:t1ejQyf8utS4GZV/4fM+1gvYucggZkfhb+tMobDxYOE=
+bitbucket.org/creachadair/stringset v0.0.14/go.mod h1:Ej8fsr6rQvmeMDf6CCWMWGb14H9mz8kmDgPPTdiVT0w=
 code.gitea.io/sdk/gitea v0.19.0 h1:8I6s1s4RHgzxiPHhOQdgim1RWIRcr0LVMbHBjBFXq4Y=
 code.gitea.io/sdk/gitea v0.19.0/go.mod h1:IG9xZJoltDNeDSW0qiF2Vqx5orMWa7OhVWrjvrd5NpI=
 dario.cat/mergo v1.0.0 h1:AGCNq9Evsj31mOgNPcLyXc+4PNABt905YmuqPYYpBWk=
@@ -323,6 +325,8 @@ github.com/hashicorp/golang-lru/arc/v2 v2.0.5 h1:l2zaLDubNhW4XO3LnliVj0GXO3+/CGN
 github.com/hashicorp/golang-lru/arc/v2 v2.0.5/go.mod h1:ny6zBSQZi2JxIeYcv7kt2sH2PXJtirBN7RDhRpxPkxU=
 github.com/hashicorp/golang-lru/v2 v2.0.5 h1:wW7h1TG88eUIJ2i69gaE3uNVtEPIagzhGvHgwfx2Vm4=
 github.com/hashicorp/golang-lru/v2 v2.0.5/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
+github.com/hexops/gotextdiff v1.0.3 h1:gitA9+qJrrTCsiCl7+kh75nPqQt1cx4ZkudSTLoUqJM=
+github.com/hexops/gotextdiff v1.0.3/go.mod h1:pSWU5MAI3yDq+fZBTazCSJysOMbxWL1BSow5/V2vxeg=
 github.com/homeport/dyff v1.7.1 h1:B3KJUtnU53H2UryxGcfYKQPrde8VjjbwlHZbczH3giQ=
 github.com/homeport/dyff v1.7.1/go.mod h1:iLe5b3ymc9xmHZNuJlNVKERE8L2isQMBLxFiTXcwZY0=
 github.com/imdario/mergo v0.3.16 h1:wwQJbIsHYGMUyLSPrEq1CT16AhnhNJQ51+4fdHUnCl4=