feat: added downloading templated archives

internal/archive/archive.go

@@ -3,6 +3,7 @@ package archive
 import (
 	"archive/tar"
 	"compress/gzip"
+	"fmt"
 	"io"
 	"os"
 	"strings"
@@ -37,27 +38,47 @@ func Expand(path string) error {
 
 func addToArchive(tw *tar.Writer, filename string, hooks []makeshift.Hook) error {
 	var (
-		hook makeshift.Hook
-		file *os.File
-		data any
-		err  error
+		tempfile = fmt.Sprintf("%s.tmp", filename)
+		file     *os.File
+		contents []byte
+		data     any
+		err      error
 	)
-	// open file to write to archive
-	file, err = os.Open(filename)
-	if err != nil {
-		return err
-	}
-	defer file.Close()
-
 	// run pre-hooks to modify the contents of the file
 	// before archiving using plugins
 	for _, hook := range hooks {
+		// set the file in the data store before running hook
+		contents, err = os.ReadFile(filename)
+		if err != nil {
+			return fmt.Errorf("failed to read '%s' to download: %v", filename, err)
+		}
+		hook.Data.Set("file", contents)
+
 		err = hook.Run()
 		if err != nil {
 			return err
 		}
+
+		// create temporary file to use to add to archive
+		hook = hooks[len(hooks)-1]
+		data, err = hook.Data.Get("out")
+		if err != nil {
+			return fmt.Errorf("failed to get output data from '%s' plugin: %v", hook.Plugin.Name(), err)
+		}
+
+		err = os.WriteFile(tempfile, data.([]byte), 0o777)
+		if err != nil {
+			return fmt.Errorf("failed to write temporary file: %v", err)
+		}
 	}
 
+	// open file to write to archive
+	file, err = os.Open(tempfile)
+	if err != nil {
+		return fmt.Errorf("failed to open temporary file: %v", err)
+	}
+	defer file.Close()
+
 	// get FileInfo for file size, mode, etc.
 	info, err := file.Stat()
 	if err != nil {
@@ -72,7 +93,7 @@ func addToArchive(tw *tar.Writer, filename string, hooks []makeshift.Hook) error
 	// create a tar Header from the FileInfo data
 	header, err := tar.FileInfoHeader(info, info.Name())
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to create FileInfoHeader: %v", err)
 	}
 
 	// use full path as name (FileInfoHeader only takes the basename) to
@@ -86,15 +107,14 @@ func addToArchive(tw *tar.Writer, filename string, hooks []makeshift.Hook) error
 		return err
 	}
 
-	// take the contents from the last hook and update files
-	hook = hooks[len(hooks)-1]
-	data, err = hook.Data.Get("out")
+	// copy file content to tar archive
+	_, err = io.Copy(tw, strings.NewReader(string(data.([]byte))))
 	if err != nil {
 		return err
 	}
 
-	// copy file content to tar archive
-	_, err = io.Copy(tw, strings.NewReader(data.(string)))
+	// delete the temporary file since we're done with it
+	err = os.Remove(tempfile)
 	if err != nil {
 		return err
 	}