Node specific overlay and templating now functioning with other minor fixups

cmd/wwbuild/overlay-utils.go

@@ -0,0 +1,90 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+
+func BuildOverlayDir(sourceDir string, destDir string, replace map[string]string) error {
+	err := os.Chdir(sourceDir)
+	if err != nil {
+		fmt.Println(err)
+		return err
+	}
+
+	err = filepath.Walk(".", func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		if info.IsDir() {
+			err := os.MkdirAll(destDir + "/" + path, info.Mode())
+			if err != nil {
+				fmt.Println(err)
+			}
+		} else {
+			if filepath.Ext(path) == ".in" {
+				destFile := strings.TrimSuffix(path, ".in")
+
+				sourceFD, err := os.Open(sourceDir + "/" + path)
+				if err != nil {
+					return err
+				}
+
+				destFD, err :=os.OpenFile(destDir + "/" + destFile, os.O_RDWR|os.O_CREATE, info.Mode())
+				if err != nil {
+					return err
+				}
+
+				scanner := bufio.NewScanner(sourceFD)
+				w := bufio.NewWriter(destFD)
+
+				for scanner.Scan() {
+					newLine := scanner.Text()
+					for k, v := range replace {
+						replaceString := fmt.Sprintf("@%s@", strings.ToUpper(k))
+						newLine = strings.ReplaceAll(newLine, replaceString, v)
+					}
+					_, err := w.WriteString(newLine + "\n")
+					if err != nil {
+						return err
+					}
+
+				}
+				w.Flush()
+				sourceFD.Close()
+				destFD.Close()
+			} else {
+				sourceFD, err := os.Open(sourceDir + "/" + path)
+				if err != nil {
+					return err
+				}
+				defer sourceFD.Close()
+
+				destFD, err := os.OpenFile(destDir + "/" + path, os.O_RDWR|os.O_CREATE, info.Mode())
+				if err != nil {
+					return err
+				}
+				defer destFD.Close()
+
+				_, err = io.Copy(destFD, sourceFD)
+				if err != nil {
+					return err
+				}
+			}
+		}
+
+		return nil
+	})
+	if err != nil {
+		fmt.Println(err)
+		return err
+	}
+
+	return nil
+}