forked from kubernetes-sigs/kustomize
/
loader.go
317 lines (293 loc) · 9.99 KB
/
loader.go
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// Copyright 2019 The Kubernetes Authors.
// SPDX-License-Identifier: Apache-2.0
package loader
import (
"fmt"
"log"
"os"
"path/filepath"
"plugin"
"reflect"
"strings"
"github.com/pkg/errors"
"sigs.k8s.io/kustomize/api/ifc"
"sigs.k8s.io/kustomize/api/internal/plugins/builtinhelpers"
"sigs.k8s.io/kustomize/api/internal/plugins/execplugin"
"sigs.k8s.io/kustomize/api/internal/plugins/fnplugin"
"sigs.k8s.io/kustomize/api/internal/plugins/utils"
"sigs.k8s.io/kustomize/api/konfig"
"sigs.k8s.io/kustomize/api/resmap"
"sigs.k8s.io/kustomize/api/resource"
"sigs.k8s.io/kustomize/api/types"
"sigs.k8s.io/kustomize/kyaml/filesys"
"sigs.k8s.io/kustomize/kyaml/resid"
)
// Loader loads plugins using a file loader (a different loader).
type Loader struct {
pc *types.PluginConfig
rf *resmap.Factory
fs filesys.FileSystem
// absolutePluginHome caches the location of a valid plugin root directory.
// It should only be set once the directory's existence has been confirmed.
absolutePluginHome string
}
func NewLoader(
pc *types.PluginConfig, rf *resmap.Factory, fs filesys.FileSystem) *Loader {
return &Loader{pc: pc, rf: rf, fs: fs}
}
// Config provides the global (not plugin specific) PluginConfig data.
func (l *Loader) Config() *types.PluginConfig {
return l.pc
}
// SetWorkDir sets the working directory for this loader's plugins
func (l *Loader) SetWorkDir(wd string) {
l.pc.FnpLoadingOptions.WorkingDir = wd
}
func (l *Loader) LoadGenerators(
ldr ifc.Loader, v ifc.Validator, rm resmap.ResMap) (
result []*resmap.GeneratorWithProperties, err error) {
for _, res := range rm.Resources() {
g, err := l.LoadGenerator(ldr, v, res)
if err != nil {
return nil, err
}
generatorOrigin, err := resource.OriginFromCustomPlugin(res)
if err != nil {
return nil, err
}
result = append(result, &resmap.GeneratorWithProperties{Generator: g, Origin: generatorOrigin})
}
return result, nil
}
func (l *Loader) LoadGenerator(
ldr ifc.Loader, v ifc.Validator, res *resource.Resource) (resmap.Generator, error) {
c, err := l.loadAndConfigurePlugin(ldr, v, res)
if err != nil {
return nil, err
}
g, ok := c.(resmap.Generator)
if !ok {
return nil, fmt.Errorf("plugin %s not a generator", res.OrgId())
}
return g, nil
}
func (l *Loader) LoadTransformers(
ldr ifc.Loader, v ifc.Validator, rm resmap.ResMap) ([]*resmap.TransformerWithProperties, error) {
var result []*resmap.TransformerWithProperties
for _, res := range rm.Resources() {
t, err := l.LoadTransformer(ldr, v, res)
if err != nil {
return nil, err
}
transformerOrigin, err := resource.OriginFromCustomPlugin(res)
if err != nil {
return nil, err
}
result = append(result, &resmap.TransformerWithProperties{Transformer: t, Origin: transformerOrigin})
}
return result, nil
}
func (l *Loader) LoadTransformer(
ldr ifc.Loader, v ifc.Validator, res *resource.Resource) (*resmap.TransformerWithProperties, error) {
c, err := l.loadAndConfigurePlugin(ldr, v, res)
if err != nil {
return nil, err
}
t, ok := c.(resmap.Transformer)
if !ok {
return nil, fmt.Errorf("plugin %s not a transformer", res.OrgId())
}
return &resmap.TransformerWithProperties{Transformer: t}, nil
}
func relativePluginPath(id resid.ResId) string {
return filepath.Join(
id.Group,
id.Version,
strings.ToLower(id.Kind))
}
func (l *Loader) AbsolutePluginPath(id resid.ResId) (string, error) {
pluginHome, err := l.absPluginHome()
if err != nil {
return "", err
}
return filepath.Join(pluginHome, relativePluginPath(id), id.Kind), nil
}
// absPluginHome is the home of kustomize Exec and Go plugins.
// Kustomize plugin configuration files are k8s-style objects
// containing the fields 'apiVersion' and 'kind', e.g.
// apiVersion: apps/v1
// kind: Deployment
// kustomize reads plugin configuration data from a file path
// specified in the 'generators:' or 'transformers:' field of a
// kustomization file. For Exec and Go plugins, kustomize
// uses this data to both locate the plugin and configure it.
// Each Exec or Go plugin (its code, its tests, its supporting data
// files, etc.) must be housed in its own directory at
// ${absPluginHome}/${pluginApiVersion}/LOWERCASE(${pluginKind})
// where
// - ${absPluginHome} is an absolute path, defined below.
// - ${pluginApiVersion} is taken from the plugin config file.
// - ${pluginKind} is taken from the plugin config file.
func (l *Loader) absPluginHome() (string, error) {
// External plugins are disabled--return the dummy plugin root.
if l.pc.PluginRestrictions != types.PluginRestrictionsNone {
return konfig.NoPluginHomeSentinal, nil
}
// We've already determined plugin home--use the cached value.
if l.absolutePluginHome != "" {
return l.absolutePluginHome, nil
}
// Check default locations for a valid plugin root, and cache it if found.
dir, err := konfig.DefaultAbsPluginHome(l.fs)
if err != nil {
return "", err
}
l.absolutePluginHome = dir
return l.absolutePluginHome, nil
}
func isBuiltinPlugin(res *resource.Resource) bool {
// TODO: the special string should appear in Group, not Version.
return res.GetGvk().Group == "" &&
res.GetGvk().Version == konfig.BuiltinPluginApiVersion
}
func (l *Loader) loadAndConfigurePlugin(
ldr ifc.Loader,
v ifc.Validator,
res *resource.Resource) (c resmap.Configurable, err error) {
if isBuiltinPlugin(res) {
switch l.pc.BpLoadingOptions {
case types.BploLoadFromFileSys:
c, err = l.loadPlugin(res)
case types.BploUseStaticallyLinked:
// Instead of looking for and loading a .so file,
// instantiate the plugin from a generated factory
// function (see "pluginator"). Being able to do this
// is what makes a plugin "builtin".
c, err = l.makeBuiltinPlugin(res.GetGvk())
default:
err = fmt.Errorf(
"unknown plugin loader behavior specified: %v",
l.pc.BpLoadingOptions)
}
} else {
switch l.pc.PluginRestrictions {
case types.PluginRestrictionsNone:
c, err = l.loadPlugin(res)
case types.PluginRestrictionsBuiltinsOnly:
err = types.NewErrOnlyBuiltinPluginsAllowed(res.OrgId().Kind)
default:
err = fmt.Errorf(
"unknown plugin restriction specified: %v",
l.pc.PluginRestrictions)
}
}
if err != nil {
return nil, err
}
yaml, err := res.AsYAML()
if err != nil {
return nil, errors.Wrapf(err, "marshalling yaml from res %s", res.OrgId())
}
err = c.Config(resmap.NewPluginHelpers(ldr, v, l.rf, l.pc), yaml)
if err != nil {
return nil, errors.Wrapf(
err, "plugin %s fails configuration", res.OrgId())
}
return c, nil
}
func (l *Loader) makeBuiltinPlugin(r resid.Gvk) (resmap.Configurable, error) {
bpt := builtinhelpers.GetBuiltinPluginType(r.Kind)
if f, ok := builtinhelpers.GeneratorFactories[bpt]; ok {
return f(), nil
}
if f, ok := builtinhelpers.TransformerFactories[bpt]; ok {
return f(), nil
}
return nil, errors.Errorf("unable to load builtin %s", r)
}
func (l *Loader) loadPlugin(res *resource.Resource) (resmap.Configurable, error) {
spec := fnplugin.GetFunctionSpec(res)
if spec != nil {
// validation check that function mounts are under the current kustomization directory
for _, mount := range spec.Container.StorageMounts {
if filepath.IsAbs(mount.Src) {
return nil, errors.New(fmt.Sprintf("plugin %s with mount path '%s' is not permitted; "+
"mount paths must be relative to the current kustomization directory", res.OrgId(), mount.Src))
}
if strings.HasPrefix(filepath.Clean(mount.Src), "../") {
return nil, errors.New(fmt.Sprintf("plugin %s with mount path '%s' is not permitted; "+
"mount paths must be under the current kustomization directory", res.OrgId(), mount.Src))
}
}
return fnplugin.NewFnPlugin(&l.pc.FnpLoadingOptions), nil
}
return l.loadExecOrGoPlugin(res.OrgId())
}
func (l *Loader) loadExecOrGoPlugin(resId resid.ResId) (resmap.Configurable, error) {
absPluginPath, err := l.AbsolutePluginPath(resId)
if err != nil {
return nil, err
}
// First try to load the plugin as an executable.
p := execplugin.NewExecPlugin(absPluginPath)
if err = p.ErrIfNotExecutable(); err == nil {
return p, nil
}
if !os.IsNotExist(err) {
// The file exists, but something else is wrong,
// likely it's not executable.
// Assume the user forgot to set the exec bit,
// and return an error, rather than adding ".so"
// to the name and attempting to load it as a Go
// plugin, which will likely fail and result
// in an obscure message.
return nil, err
}
// Failing the above, try loading it as a Go plugin.
c, err := l.loadGoPlugin(resId, absPluginPath+".so")
if err != nil {
return nil, err
}
return c, nil
}
// registry is a means to avoid trying to load the same .so file
// into memory more than once, which results in an error.
// Each test makes its own loader, and tries to load its own plugins,
// but the loaded .so files are in shared memory, so one will get
// "this plugin already loaded" errors if the registry is maintained
// as a Loader instance variable. So make it a package variable.
var registry = make(map[string]resmap.Configurable)
func (l *Loader) loadGoPlugin(id resid.ResId, absPath string) (resmap.Configurable, error) {
regId := relativePluginPath(id)
if c, ok := registry[regId]; ok {
return copyPlugin(c), nil
}
if !utils.FileExists(absPath) {
return nil, fmt.Errorf(
"expected file with Go object code at: %s", absPath)
}
log.Printf("Attempting plugin load from '%s'", absPath)
p, err := plugin.Open(absPath)
if err != nil {
return nil, errors.Wrapf(err, "plugin %s fails to load", absPath)
}
symbol, err := p.Lookup(konfig.PluginSymbol)
if err != nil {
return nil, errors.Wrapf(
err, "plugin %s doesn't have symbol %s",
regId, konfig.PluginSymbol)
}
c, ok := symbol.(resmap.Configurable)
if !ok {
return nil, fmt.Errorf("plugin '%s' not configurable", regId)
}
registry[regId] = c
return copyPlugin(c), nil
}
func copyPlugin(c resmap.Configurable) resmap.Configurable {
indirect := reflect.Indirect(reflect.ValueOf(c))
newIndirect := reflect.New(indirect.Type())
newIndirect.Elem().Set(reflect.ValueOf(indirect.Interface()))
newNamed := newIndirect.Interface()
return newNamed.(resmap.Configurable)
}