statically-embedded initializer

embedded/initializer.go

@@ -0,0 +1,120 @@
+package embedded
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+	"sort"
+
+	"github.com/markbates/pkger"
+)
+
+// DefautlContext is the default function signature / environmental context
+// of the resultant template.  All languages are expected to have at least
+// an HTTP Handler ("http") and Cloud Events ("events")
+const DefaultContext = "events"
+
+// Until such time as embedding static assets in binaries is included in the
+// base go build funcitonality (see https://github.com/golang/go/issues/35950)
+// a third-party tool is used and invoked via go-generate such that this package
+// can still be installed via go install.
+// 1) install pkger
+//    go install github.com/markbates/pkger/cmd/pkger
+// 2) Generate pkged.go (from module root):
+//    pkger -o embedded
+// 3)
+
+var defaultContexts = map[string]string{
+	"go": "events",
+}
+
+func init() {
+	pkger.Include("/templates")
+}
+
+type Initializer struct {
+	Verbose bool
+}
+
+func NewInitializer() *Initializer {
+	return &Initializer{}
+}
+
+func (n *Initializer) Initialize(language, context string, path string) error {
+	if context == "" {
+		context = DefaultContext
+	}
+
+	// TODO: Confirm the path is empty?  This is currently handled by an earlier
+	// step of the create process but future calls directly to initialize would
+	// be better off being made safe.
+
+	// TODO: since these are included in the binary statically, should we use os.PathSeparator?
+	return copy("/templates/"+language+"/"+context, path)
+}
+
+func copy(src, dest string) (err error) {
+	node, err := pkger.Stat(src)
+	if err != nil {
+		return
+	}
+	if node.IsDir() {
+		return copyNode(src, dest)
+	} else {
+		return copyLeaf(src, dest)
+	}
+}
+
+func copyNode(src, dest string) (err error) {
+	node, err := pkger.Stat(src)
+	if err != nil {
+		return
+	}
+
+	err = os.MkdirAll(dest, node.Mode())
+	if err != nil {
+		return
+	}
+
+	children, err := ReadDir(src)
+	if err != nil {
+		return
+	}
+	for _, child := range children {
+		if err = copy(filepath.Join(src, child.Name()), filepath.Join(dest, child.Name())); err != nil {
+			return
+		}
+	}
+	return
+}
+
+func ReadDir(src string) ([]os.FileInfo, error) {
+	f, err := pkger.Open(src)
+	if err != nil {
+		return nil, err
+	}
+	list, err := f.Readdir(-1)
+	f.Close()
+	if err != nil {
+		return nil, err
+	}
+	sort.Slice(list, func(i, j int) bool { return list[i].Name() < list[j].Name() })
+	return list, nil
+}
+
+func copyLeaf(src, dest string) (err error) {
+	srcFile, err := pkger.Open(src)
+	if err != nil {
+		return
+	}
+	defer srcFile.Close()
+
+	destFile, err := os.Create(dest)
+	if err != nil {
+		return
+	}
+	defer destFile.Close()
+
+	_, err = io.Copy(destFile, srcFile)
+	return
+}