Refactor normalizers

* add docs around drift detection
* move modules into subfolders to make import tree clear
* embed diffnormalize in diff package, both are small

internal/cmd/agent/deployer/applied/diff.go

@@ -6,9 +6,9 @@ import (
 	jsonpatch "github.com/evanphx/json-patch"
 
 	"github.com/rancher/fleet/internal/cmd/agent/deployer/internal/diff"
-	"github.com/rancher/fleet/internal/cmd/agent/deployer/internal/diffnormalize"
+	argo "github.com/rancher/fleet/internal/cmd/agent/deployer/internal/normalizers"
 	"github.com/rancher/fleet/internal/cmd/agent/deployer/internal/resource"
-	fleetnorm "github.com/rancher/fleet/internal/cmd/agent/deployer/normalizers"
+	"github.com/rancher/fleet/internal/cmd/agent/deployer/normalizers"
 	fleet "github.com/rancher/fleet/pkg/apis/fleet.cattle.io/v1alpha1"
 
 	"github.com/rancher/wrangler/v3/pkg/apply"
@@ -27,7 +27,7 @@ func Diff(plan apply.Plan, bd *fleet.BundleDeployment, ns string, objs ...runtim
 	desired := objectset.NewObjectSet(objs...).ObjectsByGVK()
 	live := objectset.NewObjectSet(plan.Objects...).ObjectsByGVK()
 
-	norms, err := normalizers(live, bd)
+	norms, err := newNormalizers(live, bd)
 	if err != nil {
 		return plan, err
 	}
@@ -72,6 +72,7 @@ func Diff(plan apply.Plan, bd *fleet.BundleDeployment, ns string, objs ...runtim
 				errs = append(errs, err)
 				continue
 			}
+			// this will overwrite an existing entry in the Update map
 			plan.Update.Add(gvk, key.Namespace, key.Name, string(patch))
 		}
 		if len(errs) > 0 {
@@ -81,9 +82,18 @@ func Diff(plan apply.Plan, bd *fleet.BundleDeployment, ns string, objs ...runtim
 	return plan, nil
 }
 
-func normalizers(live objectset.ObjectByGVK, bd *fleet.BundleDeployment) (diff.Normalizer, error) {
+// newNormalizers creates a normalizer that removes fields from resources.
+// The normalizer is composed of:
+//
+//   - StatusNormalizer
+//   - MutatingWebhookNormalizer
+//   - ValidatingWebhookNormalizer
+//   - normalizers.NewIgnoreNormalizer (patch.JsonPointers)
+//   - normalizers.NewKnownTypesNormalizer (rollout.argoproj.io)
+//   - patch.Operations
+func newNormalizers(live objectset.ObjectByGVK, bd *fleet.BundleDeployment) (diff.Normalizer, error) {
 	var ignore []resource.ResourceIgnoreDifferences
-	jsonPatchNorm := &fleetnorm.JSONPatchNormalizer{}
+	jsonPatchNorm := &normalizers.JSONPatchNormalizer{}
 	if bd.Spec.Options.Diff != nil {
 		for _, patch := range bd.Spec.Options.Diff.ComparePatches {
 			groupVersion, err := schema.ParseGroupVersion(patch.APIVersion)
@@ -114,11 +124,15 @@ func normalizers(live objectset.ObjectByGVK, bd *fleet.BundleDeployment) (diff.N
 		}
 	}
 
-	ignoreNorm, err := diffnormalize.NewDiffNormalizer(ignore, nil)
+	ignoreNormalizer, err := argo.NewIgnoreNormalizer(ignore, nil)
 	if err != nil {
 		return nil, err
 	}
 
-	norm := fleetnorm.New(live, ignoreNorm, jsonPatchNorm)
-	return norm, nil
+	knownTypesNorm, err := argo.NewKnownTypesNormalizer(nil)
+	if err != nil {
+		return nil, err
+	}
+
+	return normalizers.New(live, ignoreNormalizer, knownTypesNorm, jsonPatchNorm), nil
 }

internal/cmd/agent/deployer/internal/diff/diff.go

@@ -1,4 +1,4 @@
-// copied from argoproj/gitops-engine/pkg/diff/diff.go
+// +vendored argoproj/gitops-engine/pkg/diff/diff.go
 /*
 The package provide functions that allows to compare set of Kubernetes resources using the logic equivalent to
 `kubectl diff`.
@@ -21,9 +21,9 @@ import (
 	"k8s.io/apimachinery/pkg/util/strategicpatch"
 	"k8s.io/client-go/kubernetes/scheme"
 
-	jsonutil "github.com/rancher/fleet/internal/cmd/agent/deployer/internal/json"
-	"github.com/rancher/fleet/internal/cmd/agent/deployer/internal/kubernetes_vendor/pkg/api/v1/endpoints"
-	kubescheme "github.com/rancher/fleet/internal/cmd/agent/deployer/internal/scheme"
+	jsonutil "github.com/rancher/fleet/internal/cmd/agent/deployer/internal/diff/json"
+	"github.com/rancher/fleet/internal/cmd/agent/deployer/internal/diff/kubernetes_vendor/pkg/api/v1/endpoints"
+	kubescheme "github.com/rancher/fleet/internal/cmd/agent/deployer/internal/diff/scheme"
 )
 
 const couldNotMarshalErrMsg = "Could not unmarshal to object of type %s: %v"

internal/cmd/agent/deployer/internal/diff/diff_options.go

@@ -1,4 +1,4 @@
-// copied from argoproj/gitops-engine/pkg/diff/diff_options.go
+// +vendored argoproj/gitops-engine/pkg/diff/diff_options.go
 package diff
 
 import (

internal/cmd/agent/deployer/internal/json/json.go → internal/cmd/agent/deployer/internal/diff/json/json.go

@@ -1,4 +1,4 @@
-// copied from argoproj/gitops-engine/pkg/utils/json/json.go
+// +vendored argoproj/gitops-engine/pkg/utils/json/json.go
 package json
 
 // https://github.com/ksonnet/ksonnet/blob/master/pkg/kubecfg/diff.go

internal/cmd/agent/deployer/internal/kubernetes_vendor/pkg/api/v1/endpoints/util.go → internal/cmd/agent/deployer/internal/diff/kubernetes_vendor/pkg/api/v1/endpoints/util.go

@@ -22,7 +22,7 @@ import (
 	"hash"
 	"sort"
 
-	hashutil "github.com/rancher/fleet/internal/cmd/agent/deployer/internal/kubernetes_vendor/pkg/util/hash"
+	hashutil "github.com/rancher/fleet/internal/cmd/agent/deployer/internal/diff/kubernetes_vendor/pkg/util/hash"
 	v1 "k8s.io/api/core/v1"
 )
 

internal/cmd/agent/deployer/internal/scheme/scheme.go → internal/cmd/agent/deployer/internal/diff/scheme/scheme.go

@@ -1,4 +1,4 @@
-// copied from https://github.com/argoproj/gitops-engine/blob/master/pkg/utils/kube/scheme/scheme.go
+// +vendored https://github.com/argoproj/gitops-engine/blob/master/pkg/utils/kube/scheme/scheme.go
 package scheme
 
 import (

internal/cmd/agent/deployer/internal/normalizers/diff_normalizer.go

@@ -1,4 +1,7 @@
-// extracted from argoproj/argo-cd/util/argo/normalizers/diff_normalizer.go
+// Package normalizers contains normalizers for resources. Normalizers are used to modify resources before they are compared.
+// This includes the "ignore" normalizer, which removes a matched path and the knownTypes normalizer.
+//
+// +vendored argoproj/argo-cd/util/argo/normalizers/diff_normalizer.go
 package normalizers
 
 import (
@@ -11,7 +14,7 @@ import (
 	"k8s.io/apimachinery/pkg/runtime/schema"
 
 	"github.com/rancher/fleet/internal/cmd/agent/deployer/internal/diff"
-	"github.com/rancher/fleet/internal/cmd/agent/deployer/internal/glob"
+	"github.com/rancher/fleet/internal/cmd/agent/deployer/internal/normalizers/glob"
 	"github.com/rancher/fleet/internal/cmd/agent/deployer/internal/resource"
 )
 

internal/cmd/agent/deployer/internal/glob/glob.go → internal/cmd/agent/deployer/internal/normalizers/glob/glob.go

@@ -1,4 +1,4 @@
-// copied from argoproj/argo-cd/util/glob/glob.go
+// +vendored argoproj/argo-cd/util/glob/glob.go
 package glob
 
 import (

internal/cmd/agent/deployer/internal/normalizers/knowntypes_normalizer.go

@@ -1,4 +1,4 @@
-// copied from argoproj/argo-cd/util/argo/normalizers/knowntypes_normalizer.go
+// +vendored argoproj/argo-cd/util/argo/normalizers/knowntypes_normalizer.go
 package normalizers
 
 import (

internal/cmd/agent/deployer/internal/resource/ignore.go

@@ -1,4 +1,4 @@
-// extracted from argoproj/argo-cd/pkg/apis/application/v1alpha1/types.go
+// +vendored argoproj/argo-cd/pkg/apis/application/v1alpha1/types.go
 package resource
 
 import (

internal/cmd/agent/deployer/monitor/updatestatus.go

@@ -1,3 +1,6 @@
+// Package monitor provides functionality for monitoring and updating the status of a bundle deployment.
+// It includes functions for determining whether the agent should be redeployed, whether the status should be updated,
+// and for updating the status based on the resources and helm release history.
 package monitor
 
 import (
@@ -155,10 +158,15 @@ func (m *Monitor) updateFromResources(logger logr.Logger, bd *fleet.BundleDeploy
 		ns = m.defaultNamespace
 	}
 
+	// resources.Objects contains the desired state of the resources from helm history
 	plan, err := m.applied.DryRun(ns, applied.GetSetID(bd.Name, m.labelPrefix, m.labelSuffix), resources.Objects...)
 	if err != nil {
 		return err
 	}
+
+	// applied.Diff only takes plan.Update into account. plan.Update
+	// contains objects which have changes to existing values. Adding a new
+	// key to a map is not considered an update.
 	plan, err = applied.Diff(plan, bd, resources.DefaultNamespace, resources.Objects...)
 	if err != nil {
 		return err
@@ -237,6 +245,10 @@ func nonReady(logger logr.Logger, plan apply.Plan, ignoreOptions fleet.IgnoreOpt
 	return result
 }
 
+// modified returns a list of modified statuses based on the provided plan and previous release resources.
+// The function iterates through the plan's create, delete, and update actions and constructs a modified status
+// for each resource.
+// If the number of modified statuses exceeds 10, the function stops and returns the current result.
 func modified(plan apply.Plan, resourcesPreviousRelease *helmdeployer.Resources) (result []fleet.ModifiedStatus) {
 	defer func() {
 		sort.Slice(result, func(i, j int) bool {