resmap.go

// Copyright 2019 The Kubernetes Authors.
// SPDX-License-Identifier: Apache-2.0

// Package resmap implements a map from ResId to Resource that
// tracks all resources in a kustomization.
package resmap

import (
	"sigs.k8s.io/kustomize/api/ifc"
	"sigs.k8s.io/kustomize/api/resource"
	"sigs.k8s.io/kustomize/api/types"
	"sigs.k8s.io/kustomize/kyaml/kio"
	"sigs.k8s.io/kustomize/kyaml/resid"
	"sigs.k8s.io/kustomize/kyaml/yaml"
)

// A Transformer modifies an instance of ResMap.
type Transformer interface {
	// Transform modifies data in the argument,
	// e.g. adding labels to resources that can be labelled.
	Transform(m ResMap) error
}

// A TransformerWithProperties contains a Transformer and stores
// some of its properties
type TransformerWithProperties struct {
	Transformer
	Origin *resource.Origin
}

// A Generator creates an instance of ResMap.
type Generator interface {
	Generate() (ResMap, error)
}

// A GeneratorWithProperties contains a Generator and stores
// some of its properties
type GeneratorWithProperties struct {
	Generator
	Origin *resource.Origin
}

// Something that's configurable accepts an
// instance of PluginHelpers and a raw config
// object (YAML in []byte form).
type Configurable interface {
	Config(h *PluginHelpers, config []byte) error
}

// NewPluginHelpers makes an instance of PluginHelpers.
func NewPluginHelpers(
	ldr ifc.Loader, v ifc.Validator, rf *Factory,
	pc *types.PluginConfig) *PluginHelpers {
	return &PluginHelpers{ldr: ldr, v: v, rf: rf, pc: pc}
}

// PluginHelpers holds things that any or all plugins might need.
// This should be available to each plugin, in addition to
// any plugin-specific configuration.
type PluginHelpers struct {
	ldr ifc.Loader
	v   ifc.Validator
	rf  *Factory
	pc  *types.PluginConfig
}

func (c *PluginHelpers) GeneralConfig() *types.PluginConfig {
	return c.pc
}

func (c *PluginHelpers) Loader() ifc.Loader {
	return c.ldr
}

func (c *PluginHelpers) ResmapFactory() *Factory {
	return c.rf
}

func (c *PluginHelpers) Validator() ifc.Validator {
	return c.v
}

type GeneratorPlugin interface {
	Generator
	Configurable
}

type TransformerPlugin interface {
	Transformer
	Configurable
}

// ResMap is an interface describing operations on the
// core kustomize data structure, a list of Resources.
//
// Every Resource has two ResIds: OrgId and CurId.
//
// In a ResMap, no two resources may have the same CurId,
// but they may have the same OrgId.  The latter can happen
// when mixing two or more different overlays apply different
// transformations to a common base.  When looking for a
// resource to transform, try the OrgId first, and if this
// fails or finds too many, it might make sense to then try
// the CurrId.  Depends on the situation.
//
// TODO: get rid of this interface (use bare resWrangler).
// There aren't multiple implementations any more.
type ResMap interface {
	// Size reports the number of resources.
	Size() int

	// Resources provides a discardable slice
	// of resource pointers, returned in the order
	// as appended.
	Resources() []*resource.Resource

	// Append adds a Resource. Error on CurId collision.
	//
	// A class invariant of ResMap is that all of its
	// resources must differ in their value of
	// CurId(), aka current Id.  The Id is the tuple
	// of {namespace, group, version, kind, name}
	// (see ResId).
	//
	// This invariant reflects the invariant of a
	// kubernetes cluster, where if one tries to add
	// a resource to the cluster whose Id matches
	// that of a resource already in the cluster,
	// only two outcomes are allowed.  Either the
	// incoming resource is _merged_ into the existing
	// one, or the incoming resource is rejected.
	// One cannot end up with two resources
	// in the cluster with the same Id.
	Append(*resource.Resource) error

	// AppendAll appends another ResMap to self,
	// failing on any CurId collision.
	AppendAll(ResMap) error

	// AbsorbAll appends, replaces or merges the contents
	// of another ResMap into self,
	// allowing and sometimes demanding ID collisions.
	// A collision would be demanded, say, when a generated
	// ConfigMap has the "replace" option in its generation
	// instructions, meaning it _must_ replace
	// something in the known set of resources.
	// If a resource id for resource X is found to already
	// be in self, then the behavior field for X must
	// be BehaviorMerge or BehaviorReplace. If X is not in
	// self, then its behavior _cannot_ be merge or replace.
	AbsorbAll(ResMap) error

	// AddOriginAnnotation will add the provided origin as
	// an origin annotation to all resources in the ResMap, if
	// the origin is not nil.
	AddOriginAnnotation(origin *resource.Origin) error

	// RemoveOriginAnnotation will remove the origin annotation
	// from all resources in the ResMap
	RemoveOriginAnnotations() error

	// AddTransformerAnnotation will add the provided origin as
	// an origin annotation if the resource doesn't have one; a
	// transformer annotation otherwise; to all resources in
	// ResMap
	AddTransformerAnnotation(origin *resource.Origin) error

	// RemoveTransformerAnnotation will remove the transformer annotation
	// from all resources in the ResMap
	RemoveTransformerAnnotations() error

	// AnnotateAll annotates all resources in the ResMap with
	// the provided key value pair.
	AnnotateAll(key string, value string) error

	// AsYaml returns the yaml form of resources.
	AsYaml() ([]byte, error)

	// GetByIndex returns a resource at the given index,
	// nil if out of range.
	GetByIndex(int) *resource.Resource

	// GetIndexOfCurrentId returns the index of the resource
	// with the given CurId.
	// Returns error if there is more than one match.
	// Returns (-1, nil) if there is no match.
	GetIndexOfCurrentId(id resid.ResId) (int, error)

	// GetMatchingResourcesByCurrentId returns the resources
	// who's CurId is matched by the argument.
	GetMatchingResourcesByCurrentId(matches IdMatcher) []*resource.Resource

	// GetMatchingResourcesByAnyId returns the resources
	// who's current or previous IDs is matched by the argument.
	GetMatchingResourcesByAnyId(matches IdMatcher) []*resource.Resource

	// GetByCurrentId is shorthand for calling
	// GetMatchingResourcesByCurrentId with a matcher requiring
	// an exact match, returning an error on multiple or no matches.
	GetByCurrentId(resid.ResId) (*resource.Resource, error)

	// GetById is shorthand for calling
	// GetMatchingResourcesByAnyId with a matcher requiring
	// an exact match, returning an error on multiple or no matches.
	GetById(resid.ResId) (*resource.Resource, error)

	// GroupedByCurrentNamespace returns a map of namespace
	// to a slice of *Resource in that namespace.
	// Cluster-scoped Resources are not included (see ClusterScoped).
	// Resources with an empty namespace are placed
	// in the resid.DefaultNamespace entry.
	GroupedByCurrentNamespace() map[string][]*resource.Resource

	// GroupedByOriginalNamespace performs as GroupByNamespace
	// but use the original namespace instead of the current
	// one to perform the grouping.
	GroupedByOriginalNamespace() map[string][]*resource.Resource

	// ClusterScoped returns a slice of resources that
	// cannot be placed in a namespace, e.g.
	// Node, ClusterRole, Namespace itself, etc.
	ClusterScoped() []*resource.Resource

	// AllIds returns all CurrentIds.
	AllIds() []resid.ResId

	// Replace replaces the resource with the matching CurId.
	// Error if there's no match or more than one match.
	// Returns the index where the replacement happened.
	Replace(*resource.Resource) (int, error)

	// Remove removes the resource whose CurId matches the argument.
	// Error if not found.
	Remove(resid.ResId) error

	// Clear removes all resources and Ids.
	Clear()

	// DropEmpties drops empty resources from the ResMap.
	DropEmpties()

	// SubsetThatCouldBeReferencedByResource returns a ResMap subset
	// of self with resources that could be referenced by the
	// resource argument.
	// This is a filter; it excludes things that cannot be
	// referenced by the resource, e.g. objects in other
	// namespaces. Cluster wide objects are never excluded.
	SubsetThatCouldBeReferencedByResource(*resource.Resource) (ResMap, error)

	// DeAnchor replaces YAML aliases with structured data copied from anchors.
	// This cannot be undone; if desired, call DeepCopy first.
	// Subsequent marshalling to YAML will no longer have anchor
	// definitions ('&') or aliases ('*').
	//
	// Anchors are not expected to work across YAML 'documents'.
	// If three resources are loaded from one file containing three YAML docs:
	//
	//   {resourceA}
	//   ---
	//   {resourceB}
	//   ---
	//   {resourceC}
	//
	// then anchors defined in A cannot be seen from B and C and vice versa.
	// OTOH, cross-resource links (a field in B referencing fields in A) will
	// work if the resources are gathered in a ResourceList:
	//
	//   apiVersion: config.kubernetes.io/v1
	//   kind: ResourceList
	//   metadata:
	//     name: someList
	//   items:
	//   - {resourceA}
	//   - {resourceB}
	//   - {resourceC}
	//
	DeAnchor() error

	// DeepCopy copies the ResMap and underlying resources.
	DeepCopy() ResMap

	// ShallowCopy copies the ResMap but
	// not the underlying resources.
	ShallowCopy() ResMap

	// ErrorIfNotEqualSets returns an error if the
	// argument doesn't have the same resources as self.
	// Ordering is _not_ taken into account,
	// as this function was solely used in tests written
	// before internal resource order was maintained,
	// and those tests are initialized with maps which
	// by definition have random ordering, and will
	// fail spuriously.
	// TODO: modify tests to not use resmap.FromMap,
	// TODO: - and replace this with a stricter equals.
	ErrorIfNotEqualSets(ResMap) error

	// ErrorIfNotEqualLists returns an error if the
	// argument doesn't have the resource objects
	// data as self, in the same order.
	// Meta information is ignored; this is similar
	// to comparing the AsYaml() strings, but allows
	// for more informed errors on not equals.
	ErrorIfNotEqualLists(ResMap) error

	// Debug prints the ResMap.
	Debug(title string)

	// Select returns a list of resources that
	// are selected by a Selector
	Select(types.Selector) ([]*resource.Resource, error)

	// ToRNodeSlice returns a copy of the resources as RNodes.
	ToRNodeSlice() []*yaml.RNode

	// ApplySmPatch applies a strategic-merge patch to the
	// selected set of resources.
	ApplySmPatch(
		selectedSet *resource.IdSet, patch *resource.Resource) error

	// RemoveBuildAnnotations removes annotations created by the build process.
	RemoveBuildAnnotations()

	// ApplyFilter applies an RNode filter to all Resources in the ResMap.
	// TODO: Send/recover ancillary Resource data to/from subprocesses.
	// Assure that the ancillary data in Resource (everything not in the RNode)
	// is sent to and re-captured from transformer subprocess (as the process
	// might edit that information).  One way to do this would be to solely use
	// RNode metadata annotation reading and writing instead of using Resource
	// struct data members, i.e. the Resource struct is replaced by RNode
	// and use of (slow) k8s metadata annotations inside the RNode.
	ApplyFilter(f kio.Filter) error
}