Implement calculate diffs and rendering diffs of k8s

[Warashi]

What this PR does:

as title

Why we need it:

We have to calculate diffs to implement DriftDetection

Which issue(s) this PR fixes:

Part of #5363

Does this PR introduce a user-facing change?: No

• How are users affected by this change:
• Is this breaking change:
• How to migrate (if breaking change):

[codecov]

Codecov Report

Attention: Patch coverage is 96.77419% with 3 lines in your changes missing coverage. Please review.

Project coverage is 25.75%. Comparing base (20577c0) to head (0d03e64).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
pkg/app/pipedv1/plugin/kubernetes/provider/diff.go	96.77%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5674      +/-   ##
==========================================
+ Coverage   25.60%   25.75%   +0.15%     
==========================================
  Files         478      478              
  Lines       51307    51400      +93     
==========================================
+ Hits        13135    13236     +101     
+ Misses      37167    37160       -7     
+ Partials     1005     1004       -1     

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[Warashi]

ref;

pipecd/pkg/app/piped/platformprovider/kubernetes/diff.go

Lines 79 to 103 in 20577c0

	func DiffList(olds, news []Manifest, logger *zap.Logger, opts ...diff.Option) (*DiffListResult, error) {
	adds, deletes, newChanges, oldChanges := groupManifests(olds, news)
	cr := &DiffListResult{
	Adds: adds,
	Deletes: deletes,
	Changes: make([]DiffListChange, 0, len(newChanges)),
	}
	for i := 0; i < len(newChanges); i++ {
	result, err := Diff(oldChanges[i], newChanges[i], logger, opts...)
	if err != nil {
	return nil, err
	}
	if !result.HasDiff() {
	continue
	}
	cr.Changes = append(cr.Changes, DiffListChange{
	Old: oldChanges[i],
	New: newChanges[i],
	Diff: result,
	})
	}
	return cr, nil
	}

[Warashi]

ref;

pipecd/pkg/app/piped/platformprovider/kubernetes/diff.go

Lines 148 to 212 in 20577c0

	func (r *DiffListResult) Render(opt DiffRenderOptions) string {
	var b strings.Builder
	index := 0
	for _, delete := range r.Deletes {
	index++
	b.WriteString(fmt.Sprintf("- %d. %s\n\n", index, delete.Key.ReadableString()))
	}
	for _, add := range r.Adds {
	index++
	b.WriteString(fmt.Sprintf("+ %d. %s\n\n", index, add.Key.ReadableString()))
	}
	maxPrintDiffs := len(r.Changes)
	if opt.MaxChangedManifests != 0 && opt.MaxChangedManifests < maxPrintDiffs {
	maxPrintDiffs = opt.MaxChangedManifests
	}
	var prints = 0
	for _, change := range r.Changes {
	key := change.Old.Key
	opts := []diff.RenderOption{
	diff.WithLeftPadding(1),
	}
	needMaskValue := false
	if opt.MaskSecret && key.IsSecret() {
	opts = append(opts, diff.WithMaskPath("data"))
	needMaskValue = true
	} else if opt.MaskConfigMap && key.IsConfigMap() {
	opts = append(opts, diff.WithMaskPath("data"))
	needMaskValue = true
	}
	renderer := diff.NewRenderer(opts...)
	index++
	b.WriteString(fmt.Sprintf("# %d. %s\n\n", index, key.ReadableString()))
	// Use our diff check in one of the following cases:
	// - not explicit set useDiffCommand option.
	// - requires masking secret or configmap value.
	if !opt.UseDiffCommand || needMaskValue {
	b.WriteString(renderer.Render(change.Diff.Nodes()))
	} else {
	// TODO: Find a way to mask values in case of using unix `diff` command.
	d, err := diffByCommand(diffCommand, change.Old, change.New)
	if err != nil {
	b.WriteString(fmt.Sprintf("An error occurred while rendering diff (%v)", err))
	} else {
	b.Write(d)
	}
	}
	b.WriteString("\n")
	prints++
	if prints >= maxPrintDiffs {
	break
	}
	}
	if prints < len(r.Changes) {
	b.WriteString(fmt.Sprintf("... (omitted %d other changed manifests\n", len(r.Changes)-prints))
	}
	return b.String()
	}

I omit the option to use diff command to calculate diff.

[Warashi]

ref;

pipecd/pkg/app/piped/platformprovider/kubernetes/diff.go

Lines 266 to 305 in 20577c0

	func groupManifests(olds, news []Manifest) (adds, deletes, newChanges, oldChanges []Manifest) {
	// Sort the manifests before comparing.
	sort.Slice(news, func(i, j int) bool {
	return news[i].Key.IsLessWithIgnoringNamespace(news[j].Key)
	})
	sort.Slice(olds, func(i, j int) bool {
	return olds[i].Key.IsLessWithIgnoringNamespace(olds[j].Key)
	})
	var n, o int
	for {
	if n >= len(news) || o >= len(olds) {
	break
	}
	if news[n].Key.IsEqualWithIgnoringNamespace(olds[o].Key) {
	newChanges = append(newChanges, news[n])
	oldChanges = append(oldChanges, olds[o])
	n++
	o++
	continue
	}
	// Has in news but not in olds so this should be a added one.
	if news[n].Key.IsLessWithIgnoringNamespace(olds[o].Key) {
	adds = append(adds, news[n])
	n++
	continue
	}
	// Has in olds but not in news so this should be an deleted one.
	deletes = append(deletes, olds[o])
	o++
	}
	if len(news) > n {
	adds = append(adds, news[n:]...)
	}
	if len(olds) > o {
	deletes = append(deletes, olds[o:]...)
	}
	return
	}

I changed it to compare with the namespace because the plugin's implementation sets the namespace when loading and parsing manifests, so I think it's ok.

[khanhtc1202]

Here you go 👍