Make krusty package - high-level CLI-like package.

api/krusty/kustomizer.go

@@ -0,0 +1,85 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package krusty
+
+import (
+	"sigs.k8s.io/kustomize/api/filesys"
+	"sigs.k8s.io/kustomize/api/k8sdeps/kunstruct"
+	"sigs.k8s.io/kustomize/api/k8sdeps/transformer"
+	"sigs.k8s.io/kustomize/api/k8sdeps/validator"
+	fLdr "sigs.k8s.io/kustomize/api/loader"
+	"sigs.k8s.io/kustomize/api/plugins/builtins"
+	"sigs.k8s.io/kustomize/api/plugins/config"
+	pLdr "sigs.k8s.io/kustomize/api/plugins/loader"
+	"sigs.k8s.io/kustomize/api/resmap"
+	"sigs.k8s.io/kustomize/api/resource"
+	"sigs.k8s.io/kustomize/api/target"
+)
+
+// Kustomizer performs kustomizations.  It's meant to behave
+// similarly to the kustomize CLI, and can be used instead of
+// performing an exec to a kustomize CLI subprocess.
+// To use, load a filesystem with kustomization files (any
+// number of overlays and bases), then make a Kustomizer
+// injected with the given fileystem, then call Build.
+type Kustomizer struct {
+	fSys    filesys.FileSystem
+	options *Options
+}
+
+// MakeDefaultKustomizer returns a Kustomizer with default configuration.
+func MakeDefaultKustomizer() *Kustomizer {
+	return MakeKustomizer(filesys.MakeFsOnDisk(), MakeDefaultOptions())
+}
+
+// MakeKustomizer returns an instance of Kustomizer.
+func MakeKustomizer(fSys filesys.FileSystem, o *Options) *Kustomizer {
+	return &Kustomizer{fSys: fSys, options: o}
+}
+
+// Run performs a kustomization.
+//
+// It uses its internal filesystem reference to read the file at
+// the given path argument, interpret it as a kustomization.yaml
+// file, perform the kustomization it represents, and return the
+// resulting YAML as bytes.
+//
+// Any files referenced by the kustomization must be present in the
+// internal filesystem.  One may call Run any number of times,
+// on any number of internal paths (e.g. the filesystem may contain
+// multiple overlays, and Run can be called on each of them).
+func (b *Kustomizer) Run(path string) ([]byte, error) {
+	pf := transformer.NewFactoryImpl()
+	rf := resmap.NewFactory(
+		resource.NewFactory(
+			kunstruct.NewKunstructuredFactoryImpl()),
+		pf)
+	lr := fLdr.RestrictionNone
+	if b.options.RestrictToRootOnly {
+		lr = fLdr.RestrictionRootOnly
+	}
+	ldr, err := fLdr.NewLoader(lr, path, b.fSys)
+	if err != nil {
+		return nil, err
+	}
+	defer ldr.Cleanup()
+	kt, err := target.NewKustTarget(
+		ldr,
+		validator.NewKustValidator(),
+		rf,
+		pf,
+		pLdr.NewLoader(config.DefaultPluginConfig(), rf),
+	)
+	if err != nil {
+		return nil, err
+	}
+	m, err := kt.MakeCustomizedResMap()
+	if err != nil {
+		return nil, err
+	}
+	if b.options.DoLegacyResourceSort {
+		builtins.NewLegacyOrderTransformerPlugin().Transform(m)
+	}
+	return m.AsYaml()
+}