Make inventory public.

api/inventory/constants.go

@@ -0,0 +1,12 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package inventory
+
+const (
+	// Annotation that contains the inventory content.
+	ContentAnnotation = "kustomize.config.k8s.io/Inventory"
+
+	// Annotation for inventory content hash.
+	HashAnnotation = "kustomize.config.k8s.io/InventoryHash"
+)

api/inventory/inventory.go

@@ -0,0 +1,235 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package inventory
+
+import (
+	"encoding/json"
+
+	"sigs.k8s.io/kustomize/v3/api/resid"
+)
+
+//Refs is a reference map.  Each key is the id
+//of a k8s resource, and each value is a list of
+//object ids that refer back to the object in the
+//key.
+
+//For example, the key could correspond to a
+//ConfigMap, and the list of values might include
+//several different Deployments that get data from
+//that ConfigMap (and thus refer to it).
+
+//References are important in inventory management
+//because one may not delete an object before all
+//objects referencing it have been removed.
+type Refs map[resid.ResId][]resid.ResId
+
+func NewRefs() Refs {
+	return Refs{}
+}
+
+// Merge merges a Refs into an existing Refs
+func (rf Refs) Merge(b Refs) Refs {
+	for key, value := range b {
+		_, ok := rf[key]
+		if ok {
+			rf[key] = append(rf[key], value...)
+		} else {
+			rf[key] = value
+		}
+	}
+	return rf
+}
+
+// removeIfContains removes the reference relationship
+//  a --> b
+// from the Refs if it exists
+func (rf Refs) RemoveIfContains(a, b resid.ResId) {
+	refs, ok := rf[a]
+	if !ok {
+		return
+	}
+	for i, ref := range refs {
+		if ref.Equals(b) {
+			rf[a] = append(refs[:i], refs[i+1:]...)
+			break
+		}
+	}
+}
+
+//Inventory is a an object intended for
+//serialization into the annotations of a so-called
+//apply-root object (a ConfigMap, an Application,
+//etc.) living in the cluster.  This apply-root
+//object is written as part of an apply operation as
+//a means to record overall cluster state changes.
+
+//At the end of a successful apply, the "current"
+//field in Inventory will be a map whose keys all
+//correspond to an object in the cluster, and
+//"previous" will be the previous such set (an empty
+//set on the first apply).
+
+//An Inventory allows the Prune method to work.
+type Inventory struct {
+	Current  Refs `json:"current,omitempty"`
+	Previous Refs `json:"previous,omitempty"`
+}
+
+// NewInventory returns an Inventory object
+func NewInventory() *Inventory {
+	return &Inventory{
+		Current:  NewRefs(),
+		Previous: NewRefs(),
+	}
+}
+
+// UpdateCurrent updates the Inventory given a
+// new current Refs
+// The existing Current refs is merged into
+// the Previous refs
+func (a *Inventory) UpdateCurrent(curref Refs) *Inventory {
+	if len(a.Previous) > 0 {
+		a.Previous.Merge(a.Current)
+	} else {
+		a.Previous = a.Current
+	}
+	a.Current = curref
+	return a
+}
+
+func (a *Inventory) removeNewlyOrphanedItemsFromPrevious() []resid.ResId {
+	var results []resid.ResId
+	for item, refs := range a.Previous {
+		if _, ok := a.Current[item]; ok {
+			delete(a.Previous, item)
+			continue
+		}
+
+		var newRefs []resid.ResId
+		toDelete := true
+		for _, ref := range refs {
+			if _, ok := a.Current[ref]; ok {
+				toDelete = false
+				newRefs = append(newRefs, ref)
+			}
+		}
+		if toDelete {
+			results = append(results, item)
+			delete(a.Previous, item)
+		} else {
+			a.Previous[item] = newRefs
+		}
+	}
+	return results
+}
+
+func (a *Inventory) removeOrphanedItemsFromPreviousThatAreNotInCurrent() []resid.ResId {
+	var results []resid.ResId
+	for item, refs := range a.Previous {
+		if _, ok := a.Current[item]; ok {
+			continue
+		}
+		if len(refs) == 0 {
+			results = append(results, item)
+			delete(a.Previous, item)
+		}
+	}
+	return results
+}
+
+func (a *Inventory) removeOrphanedItemsFromPreviousThatAreInCurrent() {
+	//Remove references from Previous that are already in Current refs
+	for item, refs := range a.Current {
+		for _, ref := range refs {
+			a.Previous.RemoveIfContains(item, ref)
+		}
+	}
+	//Remove items from Previous that are already in Current refs
+	for item, refs := range a.Previous {
+		if len(refs) == 0 {
+			if _, ok := a.Current[item]; ok {
+				delete(a.Previous, item)
+			}
+		}
+	}
+}
+
+// Prune computes the diff of Current refs and Previous refs
+// and returns a list of Items that can be pruned.
+// An item that can be pruned shows up only in Previous refs.
+// Prune also updates the Previous refs with those items removed
+func (a *Inventory) Prune() []resid.ResId {
+	a.removeOrphanedItemsFromPreviousThatAreInCurrent()
+
+	// These are candidates for deletion from the cluster.
+	removable1 := a.removeOrphanedItemsFromPreviousThatAreNotInCurrent()
+	removable2 := a.removeNewlyOrphanedItemsFromPrevious()
+	return append(removable1, removable2...)
+}
+
+// inventory is the internal type used for serialization
+type inventory struct {
+	Current  map[string][]resid.ResId `json:"current,omitempty"`
+	Previous map[string][]resid.ResId `json:"previous,omitempty"`
+}
+
+func (a *Inventory) toInternalType() inventory {
+	prev := map[string][]resid.ResId{}
+	curr := map[string][]resid.ResId{}
+	for id, refs := range a.Current {
+		curr[id.String()] = refs
+	}
+	for id, refs := range a.Previous {
+		prev[id.String()] = refs
+	}
+	return inventory{
+		Current:  curr,
+		Previous: prev,
+	}
+}
+
+func (a *Inventory) fromInternalType(i *inventory) {
+	for s, refs := range i.Previous {
+		a.Previous[resid.FromString(s)] = refs
+	}
+	for s, refs := range i.Current {
+		a.Current[resid.FromString(s)] = refs
+	}
+}
+
+func (a *Inventory) marshal() ([]byte, error) {
+	return json.Marshal(a.toInternalType())
+}
+
+func (a *Inventory) unMarshal(data []byte) error {
+	inv := &inventory{
+		Current:  map[string][]resid.ResId{},
+		Previous: map[string][]resid.ResId{},
+	}
+	err := json.Unmarshal(data, inv)
+	if err != nil {
+		return err
+	}
+	a.fromInternalType(inv)
+	return nil
+}
+
+// UpdateAnnotations update the annotation map
+func (a *Inventory) UpdateAnnotations(annot map[string]string) error {
+	data, err := a.marshal()
+	if err != nil {
+		return err
+	}
+	annot[ContentAnnotation] = string(data)
+	return nil
+}
+
+// LoadFromAnnotation loads the Inventory date from the annotation map
+func (a *Inventory) LoadFromAnnotation(annot map[string]string) error {
+	value, ok := annot[ContentAnnotation]
+	if ok {
+		return a.unMarshal([]byte(value))
+	}
+	return nil
+}

api/inventory/inventory_test.go

@@ -0,0 +1,60 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package inventory_test
+
+import (
+	"testing"
+
+	. "sigs.k8s.io/kustomize/v3/api/inventory"
+	"sigs.k8s.io/kustomize/v3/api/resid"
+)
+
+func makeRefs() (Refs, Refs) {
+	a := resid.FromString("G1_V1_K1|ns1|nm1")
+	b := resid.FromString("G2_V2_K2|ns2|nm2")
+	c := resid.FromString("G3_V3_K3|ns3|nm3")
+	current := NewRefs()
+	current[a] = []resid.ResId{b, c}
+	current[b] = []resid.ResId{}
+	current[c] = []resid.ResId{}
+	newRefs := NewRefs()
+	newRefs[a] = []resid.ResId{b}
+	newRefs[b] = []resid.ResId{}
+	return current, newRefs
+}
+
+func TestInventory(t *testing.T) {
+	inventory := NewInventory()
+	curref, _ := makeRefs()
+
+	inventory.UpdateCurrent(curref)
+	if len(inventory.Current) != 3 {
+		t.Fatalf("not getting the correct inventory %v", inventory)
+	}
+	curref, newref := makeRefs()
+	inventory.UpdateCurrent(curref)
+	if len(inventory.Current) != 3 {
+		t.Fatalf("not getting the corrent inventory %v", inventory)
+	}
+	if len(inventory.Previous) != 3 {
+		t.Fatalf("not getting the corrent inventory %v", inventory)
+	}
+
+	items := inventory.Prune()
+	if len(items) != 0 {
+		t.Fatalf("not getting the corrent items %v", items)
+	}
+	if len(inventory.Previous) != 0 {
+		t.Fatalf("not getting the corrent inventory %v", inventory)
+	}
+
+	inventory.UpdateCurrent(newref)
+	items = inventory.Prune()
+	if len(items) != 1 {
+		t.Fatalf("not getting the corrent items %v", items)
+	}
+	if len(inventory.Previous) != 0 {
+		t.Fatalf("not getting the corrent inventory %v", inventory.Previous)
+	}
+}