// exportCodelab fetches codelab src from either local disk or remote,
// parses and stores the results on disk, in a dir ancestored by *output.
//
// Stored results include codelab content formatted in *tmplout, its assets
// and metadata in JSON format.
//
// There's a special case where basedir has a value of "-", in which
// nothing is stored on disk and the only output, codelab formatted content,
// is printed to stdout.
func exportCodelab(src string) (*types.Meta, error) {
clab, err := slurpCodelab(src)
if err != nil {
return nil, err
}
var client *http.Client // need for downloadImages
if clab.typ == srcGoogleDoc {
client, err = driveClient()
if err != nil {
return nil, err
}
}
// codelab export context
lastmod := types.ContextTime(clab.mod)
meta := &clab.Meta
ctx := &types.Context{
Source: src,
Env: *expenv,
Format: *tmplout,
Prefix: *prefix,
MainGA: *globalGA,
Updated: &lastmod,
}
// rewritten image urls
var imap map[string]string
dir := *output // output dir or stdout
if !isStdout(dir) {
dir = codelabDir(dir, meta)
imap = rewriteImages(clab.Steps)
}
// write codelab and its metadata to disk
if err := writeCodelab(dir, clab.Codelab, ctx); err != nil {
return nil, err
}
// slurp codelab assets to disk, if any
mdir := filepath.Join(dir, imgDirname)
return meta, downloadImages(client, mdir, imap)
}
// updateCodelab reads metadata from a dir/codelab.json file,
// re-exports the codelab just like it normally would in exportCodelab,
// and removes assets (images) which are not longer in use.
func updateCodelab(dir string) (*types.Meta, error) {
// get stored codelab metadata and fail early if we can't
meta, err := readMeta(filepath.Join(dir, metaFilename))
if err != nil {
return nil, err
}
// override allowed options from cli
if *prefix != "" {
meta.Prefix = *prefix
}
if *globalGA != "" {
meta.MainGA = *globalGA
}
// fetch and parse codelab source
clab, err := slurpCodelab(meta.Source)
if err != nil {
return nil, err
}
updated := types.ContextTime(clab.mod)
meta.Context.Updated = &updated
// update image references before writing codelab
imgmap := rewriteImages(clab.Steps)
basedir := filepath.Join(dir, "..")
newdir := codelabDir(basedir, &clab.Meta)
if err := writeCodelab(newdir, clab.Codelab, &meta.Context); err != nil {
return nil, err
}
// slurp codelab assets to disk
var client *http.Client
if clab.typ == srcGoogleDoc {
client, err = driveClient()
if err != nil {
return nil, err
}
}
imgdir := filepath.Join(newdir, imgDirname)
if err := downloadImages(client, imgdir, imgmap); err != nil {
return nil, err
}
// cleanup:
// - remove original dir if codelab ID has changed and so has the output dir
// - otherwise, remove images which are not in imgs
old := codelabDir(basedir, &meta.Meta)
if old != newdir {
return &meta.Meta, os.RemoveAll(old)
}
visit := func(p string, fi os.FileInfo, err error) error {
if err != nil || p == imgdir {
return err
}
if fi.IsDir() {
return filepath.SkipDir
}
if _, ok := imgmap[filepath.Base(p)]; !ok {
return os.Remove(p)
}
return nil
}
return &meta.Meta, filepath.Walk(imgdir, visit)
}