add inventory package and refactor inventory transformer

pkg/inventory/constants.go

@@ -0,0 +1,25 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package inventory
+
+const (
+	// the annotation for inventory hash
+	InventoryHashAnnotation = "kustomize.config.k8s.io/InventoryHash"
+
+	// the annotation that contains the inventory information
+	InventoryAnnotation = "kustomize.config.k8s.io/Inventory"
+)

pkg/inventory/inventory.go

@@ -0,0 +1,173 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package inventory
+
+import (
+	"encoding/json"
+
+	"sigs.k8s.io/kustomize/pkg/resid"
+)
+
+// A Refs is a map from an Item string to a list of Items
+// that it is referred
+type Refs map[string][]resid.ItemId
+
+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 string, b resid.ItemId) {
+	refs, ok := rf[a]
+	if !ok {
+		return
+	}
+	for i, ref := range refs {
+		if ref.String() == b.String() {
+			rf[a] = append(refs[:i], refs[i+1:]...)
+			break
+		}
+	}
+}
+
+// An Inventory contains current refs
+// and previous refs
+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
+}
+
+// Prune returns a list of Items that can be pruned
+// as well as updates the Inventory
+func (a *Inventory) Prune() []resid.ItemId {
+	var results []resid.ItemId
+	curref := a.Current
+
+	// Remove references that are already in Current refs
+	for item, refs := range curref {
+		for _, ref := range refs {
+			a.Previous.RemoveIfContains(item, ref)
+		}
+	}
+	// Remove items that are already in Current refs
+	for item, refs := range a.Previous {
+		if len(refs) == 0 {
+			if _, ok := curref[item]; ok {
+				delete(a.Previous, item)
+			}
+		}
+	}
+
+	// Remove items from the Previous refs
+	// that are not referred by others
+	for item, refs := range a.Previous {
+		if _, ok := curref[item]; ok {
+			continue
+		}
+		if len(refs) == 0 {
+			results = append(results, resid.FromString(item))
+			delete(a.Previous, item)
+		}
+	}
+
+	// Remove items from the Previous refs
+	// that are referred only by to be deleted items
+	for item, refs := range a.Previous {
+		if _, ok := curref[item]; ok {
+			delete(a.Previous, item)
+			continue
+		}
+
+		var newRefs []resid.ItemId
+		toDelete := true
+		for _, ref := range refs {
+			if _, ok := curref[ref.String()]; ok {
+				toDelete = false
+				newRefs = append(newRefs, ref)
+			}
+		}
+		if toDelete {
+			results = append(results, resid.FromString(item))
+			delete(a.Previous, item)
+		} else {
+			a.Previous[item] = newRefs
+		}
+	}
+	return results
+}
+
+func (a *Inventory) marshal() ([]byte, error) {
+	return json.Marshal(a)
+}
+
+func (a *Inventory) unMarshal(data []byte) error {
+	return json.Unmarshal(data, a)
+}
+
+func (a *Inventory) UpdateAnnotations(annot map[string]string) error {
+	data, err := a.marshal()
+	if err != nil {
+		return err
+	}
+	annot[InventoryAnnotation] = string(data)
+	return nil
+}
+
+func (a *Inventory) LoadFromAnnotation(annot map[string]string) error {
+	value, ok := annot[InventoryAnnotation]
+	if ok {
+		return a.unMarshal([]byte(value))
+	}
+	return nil
+}

pkg/inventory/inventory_test.go

@@ -0,0 +1,72 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package inventory
+
+import (
+	"testing"
+
+	"sigs.k8s.io/kustomize/pkg/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.String()] = []resid.ItemId{b, c}
+	current[b.String()] = []resid.ItemId{}
+	current[c.String()] = []resid.ItemId{}
+	new := NewRefs()
+	new[a.String()] = []resid.ItemId{b}
+	new[b.String()] = []resid.ItemId{}
+	return current, new
+}
+
+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)
+	}
+}