create zip archive

.gitignore

@@ -1,2 +1,4 @@
 # binary file
-packer
+packer
+# zip file
+*.zip

main.go

@@ -3,8 +3,10 @@
 package main
 
 import (
+	"archive/zip"
 	"fmt"
 	"github.com/akamensky/argparse"
+	"io"
 	"log"
 	"os"
 	fp "path/filepath"
@@ -48,7 +50,7 @@ func walkDirFiltered(directory string, regex re.Regexp) ([]string, error) {
 				return err
 			}
 			if !info.IsDir() && regex.MatchString(path) {
-				fmt.Println(path)
+				log.Println("file found :", path)
 				files = append(files, path)
 			}
 			return err
@@ -62,6 +64,70 @@ func getFilesFromDirectoryPath(directory string, regex re.Regexp) ([]string, err
 	return files, err
 }
 
+// writeFileContent - write file content into zipped file
+// chunking is used to avoid memory errors with large files
+func writeFileContent(f *os.File, zf io.Writer) (err error) {
+	const chunkSize = 4
+	b := make([]byte, chunkSize)
+
+	for {
+		_, err := f.Read(b)
+		if err != nil {
+			if err != io.EOF {
+				continue
+			}
+			break
+		}
+		zf.Write(b)
+	}
+
+	return err
+}
+
+// generateZip - create a zip archive
+// * outputPath: zip archive full path
+// * filePaths: files path
+func generateZip(outputPath string, filepaths []string) (err error) {
+
+	// create a zipfile from `outputPath`
+	zipPath, err := os.Create(outputPath)
+	if err != nil {
+		return err
+	}
+	defer zipPath.Close()
+
+	// create a new zip archive from `zipPath`
+	w := zip.NewWriter(zipPath)
+
+	for _, filepath := range filepaths {
+		// open matching regex file
+		f, err := os.Open(filepath)
+		if err != nil {
+			log.Println("[ERROR] :", err)
+			continue
+		}
+
+		// create a zipped file
+		zf, err := w.Create(filepath)
+		if err != nil {
+			log.Println("[ERROR] :", err)
+			f.Close()
+			continue
+		}
+
+		// write file content into zipped file
+		err = writeFileContent(f, zf)
+
+		// clean up opened file
+		f.Close()
+	}
+
+	// make sure to check the error on Close.
+	err = w.Close()
+
+	return err
+}
+
 func main() {
 
 	// parse arguments
@@ -83,6 +149,9 @@ func main() {
 	log.Printf("looking for file '%s' in '%s' ...", rd.String(), directory)
 	files, err := getFilesFromDirectoryPath(directory, rd)
 
+	// generating zip archive
 	log.Printf("files found : %d", len(files))
-	log.Printf("files zipped in %s", outputPath)
+	generateZip(outputPath, files)
+
+	log.Printf("zip archive generated in %s", outputPath)
 }