/
extension.go
395 lines (346 loc) · 11 KB
/
extension.go
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package common
import (
"bufio"
"crypto/sha1"
"encoding/hex"
"fmt"
"io"
"io/ioutil"
"net/http"
"net/url"
"os"
"path/filepath"
"regexp"
"github.com/mholt/archiver"
"github.com/mitchellh/go-homedir"
"gopkg.in/yaml.v2"
)
// ExtensionImpl provides API for an extension
type ExtensionImpl interface {
ID() string
DecorateStackTemplate(assetName string, stackName string, templateBody io.Reader) (io.Reader, error)
DecorateStackParameters(stackName string, stackParameters map[string]string) (map[string]string, error)
DecorateStackTags(stackName string, stackTags map[string]string) (map[string]string, error)
}
// BaseExtensionImpl basic no-op extension
type BaseExtensionImpl struct {
id string
}
// DecorateStackTemplate don't decorate, just return
func (ext *BaseExtensionImpl) DecorateStackTemplate(assetName string, stackName string, inTemplate io.Reader) (io.Reader, error) {
return inTemplate, nil
}
// DecorateStackParameters don't decorate, just return
func (ext *BaseExtensionImpl) DecorateStackParameters(stackName string, stackParameters map[string]string) (map[string]string, error) {
return stackParameters, nil
}
// DecorateStackTags don't decorate, just return
func (ext *BaseExtensionImpl) DecorateStackTags(stackName string, stackTags map[string]string) (map[string]string, error) {
return stackTags, nil
}
// ID returns unique id for extension
func (ext *BaseExtensionImpl) ID() string {
return ext.id
}
// ExtensionsManager provides API for running extensions
type ExtensionsManager interface {
ExtensionImpl
AddExtension(extension ExtensionImpl) error
}
// Implementation of ExtensionsManager
type extensionsManager struct {
BaseExtensionImpl
extensions []ExtensionImpl
}
// Create a new extensionsManager
func newExtensionsManager() (ExtensionsManager, error) {
extMgr := &extensionsManager{
BaseExtensionImpl{""},
make([]ExtensionImpl, 0),
}
return extMgr, nil
}
func (extMgr *extensionsManager) AddExtension(extension ExtensionImpl) error {
if extension == nil {
return fmt.Errorf("extension was nil")
}
// ensure extension isn't already loaded
for _, existingExt := range extMgr.extensions {
if existingExt.ID() == extension.ID() {
return fmt.Errorf("extension '%s' already loaded...skipping", extension.ID())
}
}
extMgr.extensions = append(extMgr.extensions, extension)
return nil
}
// DecorateStackTemplate for all extensions
func (extMgr *extensionsManager) DecorateStackTemplate(assetName string, stackName string, inTemplate io.Reader) (io.Reader, error) {
outTemplate := inTemplate
for _, ext := range extMgr.extensions {
var err error
outTemplate, err = ext.DecorateStackTemplate(assetName, stackName, outTemplate)
if err != nil {
return nil, err
}
}
return outTemplate, nil
}
// DecorateStackParameters for all extensions
func (extMgr *extensionsManager) DecorateStackParameters(stackName string, stackParameters map[string]string) (map[string]string, error) {
outParams := stackParameters
for _, ext := range extMgr.extensions {
var err error
outParams, err = ext.DecorateStackParameters(stackName, outParams)
if err != nil {
return nil, err
}
}
return outParams, nil
}
// DecorateStackTags for all extensions
func (extMgr *extensionsManager) DecorateStackTags(stackName string, stackTags map[string]string) (map[string]string, error) {
outTags := stackTags
for _, ext := range extMgr.extensions {
var err error
outTags, err = ext.DecorateStackTags(stackName, outTags)
if err != nil {
return nil, err
}
}
return outTags, nil
}
// Extension for template overrides in mu.yml
type templateOverrideExtension struct {
BaseExtensionImpl
stackNameMatcher *regexp.Regexp
decoration interface{}
}
func newTemplateOverrideExtension(stackNamePattern string, template interface{}) ExtensionImpl {
id := fmt.Sprintf("templateOverride:%s", stackNamePattern)
ext := &templateOverrideExtension{
BaseExtensionImpl{id},
regexp.MustCompile(fmt.Sprintf("^%s$", stackNamePattern)),
template,
}
return ext
}
// DecorateStackTemplate from overrides in mu.yml
func (ext *templateOverrideExtension) DecorateStackTemplate(assetName string, stackName string, inTemplate io.Reader) (io.Reader, error) {
if stackName != "" && ext.stackNameMatcher.MatchString(stackName) {
return decorateTemplate(inTemplate, ext.decoration)
}
return inTemplate, nil
}
// Extension for tag overrides in mu.yml
type tagOverrideExtension struct {
BaseExtensionImpl
stackNameMatcher *regexp.Regexp
tags map[string]string
}
func newTagOverrideExtension(stackNamePattern string, tags map[string]string) ExtensionImpl {
id := fmt.Sprintf("tagOverride:%s", stackNamePattern)
ext := &tagOverrideExtension{
BaseExtensionImpl{id},
regexp.MustCompile(fmt.Sprintf("^%s$", stackNamePattern)),
tags,
}
return ext
}
// DecorateStackTags from overrides in mu.yml
func (ext *tagOverrideExtension) DecorateStackTags(stackName string, stackTags map[string]string) (map[string]string, error) {
if ext.stackNameMatcher.MatchString(stackName) {
for k, v := range ext.tags {
stackTags[k] = v
}
}
return stackTags, nil
}
// Extension for param overrides in mu.yml
type paramOverrideExtension struct {
BaseExtensionImpl
stackNameMatcher *regexp.Regexp
params map[string]string
}
func newParameterOverrideExtension(stackNamePattern string, params map[string]string) ExtensionImpl {
id := fmt.Sprintf("paramOverride:%s", stackNamePattern)
ext := ¶mOverrideExtension{
BaseExtensionImpl{id},
regexp.MustCompile(fmt.Sprintf("^%s$", stackNamePattern)),
params,
}
return ext
}
// DecorateStackParameters from overrides in mu.yml
func (ext *paramOverrideExtension) DecorateStackParameters(stackName string, stackParams map[string]string) (map[string]string, error) {
if ext.stackNameMatcher.MatchString(stackName) {
for k, v := range ext.params {
stackParams[k] = v
}
}
return stackParams, nil
}
// Extension for archives of templates
type templateArchiveExtension struct {
BaseExtensionImpl
path string
mode TemplateUpdateMode
}
// TemplateUpdateMode of valid template update modes
type TemplateUpdateMode string
// list of update modes
const (
TemplateUpdateReplace TemplateUpdateMode = "replace"
TemplateUpdateMerge = "merge"
)
func loadExtensionFromArchive(ext *templateArchiveExtension,
artifactManager ArtifactManager,
extensionURL *url.URL) error {
// check for existing etag
etag := ""
etagBytes, err := ioutil.ReadFile(filepath.Join(ext.path, ".etag"))
if err == nil {
etag = string(etagBytes)
}
body, etag, err := artifactManager.GetArtifact(extensionURL.String(), etag)
if err != nil {
return err
}
if body != nil {
defer body.Close()
// empty dir
os.RemoveAll(ext.path)
os.MkdirAll(ext.path, 0700)
// write out archive to dir
err = extractArchive(ext.path, body)
if err != nil {
return err
}
// if single directory in extension, assume that's the path
files, err := ioutil.ReadDir(ext.path)
if err != nil {
return err
}
originalExtPath := ext.path
if len(files) == 1 && files[0].IsDir() {
ext.path = filepath.Join(originalExtPath, files[0].Name())
log.Debugf("Using directory '%s' for extension '%s'", ext.path, extensionURL)
}
// write new etag
err = ioutil.WriteFile(filepath.Join(originalExtPath, ".etag"), []byte(etag), 0644)
if err != nil {
return err
}
log.Debugf("Loaded extension from '%s' [id=%s]", extensionURL, ext.id)
} else {
log.Debugf("Loaded extension from cache [id=%s]", ext.id)
}
return nil
}
func newTemplateArchiveExtension(extensionURL *url.URL, artifactManager ArtifactManager) (ExtensionImpl, error) {
log.Debugf("Loading extension from '%s'", extensionURL)
userdir, err := homedir.Dir()
if err != nil {
return nil, err
}
extensionsDirectory := filepath.Join(userdir, ".mu", "extensions")
extID := urlToID(extensionURL)
ext := &templateArchiveExtension{
BaseExtensionImpl{extensionURL.String()},
filepath.Join(extensionsDirectory, extID),
TemplateUpdateMerge,
}
if fi, err := os.Stat(extensionURL.Path); extensionURL.Scheme == "file" && err == nil && fi.IsDir() {
ext.path = extensionURL.Path
log.Debugf("Loaded extension from '%s'", extensionURL.Path)
} else {
err := loadExtensionFromArchive(ext,
artifactManager,
extensionURL)
if err != nil {
return nil, err
}
}
// try loading the extension manifest
extManifest := make(map[interface{}]interface{})
extManifestFile, err := ioutil.ReadFile(filepath.Join(ext.path, "mu-extension.yml"))
if err == nil {
err = yaml.Unmarshal(extManifestFile, extManifest)
if err != nil {
log.Debugf("error unmarshalling mu-extension.yml: %s", err)
} else {
if v, ok := extManifest["templateUpdateMode"]; ok {
ext.mode = TemplateUpdateMode(v.(string))
}
}
} else {
log.Debugf("error reading mu-extension.yml: %s", err)
}
// log info about the new extension
if name, ok := extManifest["name"]; ok {
if version, ok := extManifest["version"]; ok {
log.Warningf("Loaded extension %s (version=%v)", name, version)
} else {
log.Warningf("Loaded extension %s", name)
}
} else {
log.Warningf("Loaded extension %s", extensionURL)
}
return ext, nil
}
// DecorateStackTemplate from template files in archive
func (ext *templateArchiveExtension) DecorateStackTemplate(assetName string, stackName string, inTemplate io.Reader) (io.Reader, error) {
if assetName == "" {
return inTemplate, nil
}
outTemplate := inTemplate
assetPath := filepath.Join(ext.path, assetName)
if _, err := os.Stat(assetPath); os.IsNotExist(err) {
log.Debugf("Path missing, trying without directory: %s", assetPath)
_, assetName = filepath.Split(assetPath)
assetPath = filepath.Join(ext.path, assetName)
}
if ext.mode == TemplateUpdateReplace {
f, err := os.Open(assetPath)
if err != nil {
log.Debugf("Error trying to replace template '%s': %v", assetName, err)
return inTemplate, nil
}
log.Debugf("Replacing input template '%s'", assetName)
return f, nil
}
yamlFile, err := ioutil.ReadFile(assetPath)
if err != nil {
log.Debugf("Unable to find asset '%s' in extension '%s': %s", assetName, ext.id, err)
} else {
decoration := make(map[interface{}]interface{})
err = yaml.Unmarshal(yamlFile, decoration)
if err != nil {
log.Warningf("Unable to parse asset '%s' in extension '%s': %s", assetName, ext.id, err)
} else {
return decorateTemplate(inTemplate, decoration)
}
}
return outTemplate, nil
}
func urlToID(u *url.URL) string {
h := sha1.New()
h.Write([]byte(u.String()))
return hex.EncodeToString(h.Sum(nil))
}
func extractArchive(destPath string, archive io.ReadCloser) error {
reader := bufio.NewReader(archive)
headBytes, err := reader.Peek(512)
if err != nil {
return err
}
contentType := http.DetectContentType(headBytes)
log.Debugf("Extracting type '%s'", contentType)
switch contentType {
case "application/x-gzip":
return archiver.TarGz.Read(reader, destPath)
case "application/zip":
return archiver.Zip.Read(reader, destPath)
default:
return fmt.Errorf("unable to handle archive of content-type '%s'", contentType)
}
}