Start api directory, which will become a module.

api/types/var.go

@@ -0,0 +1,213 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package types
+
+import (
+	"fmt"
+	"reflect"
+	"sort"
+	"strings"
+
+	"sigs.k8s.io/kustomize/v3/api/resid"
+)
+
+const defaultFieldPath = "metadata.name"
+
+// Var represents a variable whose value will be sourced
+// from a field in a Kubernetes object.
+type Var struct {
+	// Value of identifier name e.g. FOO used in container args, annotations
+	// Appears in pod template as $(FOO)
+	Name string `json:"name" yaml:"name"`
+
+	// ObjRef must refer to a Kubernetes resource under the
+	// purview of this kustomization. ObjRef should use the
+	// raw name of the object (the name specified in its YAML,
+	// before addition of a namePrefix and a nameSuffix).
+	ObjRef Target `json:"objref" yaml:"objref"`
+
+	// FieldRef refers to the field of the object referred to by
+	// ObjRef whose value will be extracted for use in
+	// replacing $(FOO).
+	// If unspecified, this defaults to fieldPath: $defaultFieldPath
+	FieldRef FieldSelector `json:"fieldref,omitempty" yaml:"fieldref,omitempty"`
+}
+
+// Target refers to a kubernetes object by Group, Version, Kind and Name
+// gvk.Gvk contains Group, Version and Kind
+// APIVersion is added to keep the backward compatibility of using ObjectReference
+// for Var.ObjRef
+type Target struct {
+	APIVersion string `json:"apiVersion,omitempty" yaml:"apiVersion,omitempty"`
+	resid.Gvk  `json:",inline,omitempty" yaml:",inline,omitempty"`
+	Name       string `json:"name" yaml:"name"`
+	Namespace  string `json:"namespace,omitempty" yaml:"namespace,omitempty"`
+}
+
+// GVK returns the Gvk object in Target
+func (t *Target) GVK() resid.Gvk {
+	if t.APIVersion == "" {
+		return t.Gvk
+	}
+	versions := strings.Split(t.APIVersion, "/")
+	if len(versions) == 2 {
+		t.Group = versions[0]
+		t.Version = versions[1]
+	}
+	if len(versions) == 1 {
+		t.Version = versions[0]
+	}
+	return t.Gvk
+}
+
+// FieldSelector contains the fieldPath to an object field.
+// This struct is added to keep the backward compatibility of using ObjectFieldSelector
+// for Var.FieldRef
+type FieldSelector struct {
+	FieldPath string `json:"fieldPath,omitempty" yaml:"fieldPath,omitempty"`
+}
+
+// defaulting sets reference to field used by default.
+func (v *Var) Defaulting() {
+	if v.FieldRef.FieldPath == "" {
+		v.FieldRef.FieldPath = defaultFieldPath
+	}
+	v.ObjRef.GVK()
+}
+
+// DeepEqual returns true if var a and b are Equals.
+// Note 1: The objects are unchanged by the VarEqual
+// Note 2: Should be normalize be FieldPath before doing
+// the DeepEqual. spec.a[b] is supposed to be the same
+// as spec.a.b
+func (v Var) DeepEqual(other Var) bool {
+	v.Defaulting()
+	other.Defaulting()
+	return reflect.DeepEqual(v, other)
+}
+
+// VarSet is a set of Vars where no var.Name is repeated.
+type VarSet struct {
+	set map[string]Var
+}
+
+// NewVarSet returns an initialized VarSet
+func NewVarSet() VarSet {
+	return VarSet{set: map[string]Var{}}
+}
+
+// AsSlice returns the vars as a slice.
+func (vs *VarSet) AsSlice() []Var {
+	s := make([]Var, len(vs.set))
+	i := 0
+	for _, v := range vs.set {
+		s[i] = v
+		i++
+	}
+	sort.Sort(byName(s))
+	return s
+}
+
+// Copy returns a copy of the var set.
+func (vs *VarSet) Copy() VarSet {
+	newSet := make(map[string]Var, len(vs.set))
+	for k, v := range vs.set {
+		newSet[k] = v
+	}
+	return VarSet{set: newSet}
+}
+
+// MergeSet absorbs other vars with error on name collision.
+func (vs *VarSet) MergeSet(incoming VarSet) error {
+	for _, incomingVar := range incoming.set {
+		if err := vs.Merge(incomingVar); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// MergeSlice absorbs a Var slice with error on name collision.
+// Empty fields in incoming vars are defaulted.
+func (vs *VarSet) MergeSlice(incoming []Var) error {
+	for _, v := range incoming {
+		if err := vs.Merge(v); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Merge absorbs another Var with error on name collision.
+// Empty fields in incoming Var is defaulted.
+func (vs *VarSet) Merge(v Var) error {
+	if vs.Contains(v) {
+		return fmt.Errorf(
+			"var '%s' already encountered", v.Name)
+	}
+	v.Defaulting()
+	vs.set[v.Name] = v
+	return nil
+}
+
+// AbsorbSet absorbs other vars with error on (name,value) collision.
+func (vs *VarSet) AbsorbSet(incoming VarSet) error {
+	for _, v := range incoming.set {
+		if err := vs.Absorb(v); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// AbsorbSlice absorbs a Var slice with error on (name,value) collision.
+// Empty fields in incoming vars are defaulted.
+func (vs *VarSet) AbsorbSlice(incoming []Var) error {
+	for _, v := range incoming {
+		if err := vs.Absorb(v); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Absorb absorbs another Var with error on (name,value) collision.
+// Empty fields in incoming Var is defaulted.
+func (vs *VarSet) Absorb(v Var) error {
+	conflicting := vs.Get(v.Name)
+	if conflicting == nil {
+		// no conflict. The var is valid.
+		v.Defaulting()
+		vs.set[v.Name] = v
+		return nil
+	}
+
+	if !reflect.DeepEqual(v, *conflicting) {
+		// two vars with the same name are pointing at two
+		// different resources.
+		return fmt.Errorf(
+			"var '%s' already encountered", v.Name)
+	}
+	return nil
+}
+
+// Contains is true if the set has the other var.
+func (vs *VarSet) Contains(other Var) bool {
+	return vs.Get(other.Name) != nil
+}
+
+// Get returns the var with the given name, else nil.
+func (vs *VarSet) Get(name string) *Var {
+	if v, found := vs.set[name]; found {
+		return &v
+	}
+	return nil
+}
+
+// byName is a sort interface which sorts Vars by name alphabetically
+type byName []Var
+
+func (v byName) Len() int           { return len(v) }
+func (v byName) Swap(i, j int)      { v[i], v[j] = v[j], v[i] }
+func (v byName) Less(i, j int) bool { return v[i].Name < v[j].Name }