walk into directory and filter filename with regex

main.go

@@ -1,10 +1,14 @@
+// packer - a simple CLI tool to find and zip file corresponding to a given regex
+// find + zip linux CLI works too
 package main
 
 import (
+	"fmt"
 	"github.com/akamensky/argparse"
 	"log"
 	"os"
-	"fmt"
+	fp "path/filepath"
+	re "regexp"
 )
 
 // parseArguments - get needed arguments to launch the `packer`
@@ -25,17 +29,60 @@ func parseArguments() (string, string, string, error) {
 		err = fmt.Errorf("parsing error: %s", parseError)
 	}
 
-	return *regex, *outputPath, *directory, err
+	return *regex, *directory, *outputPath, err
+}
+
+// buildRegex - build POSIX regex from a string
+// WARN: lookahead and lookbehind are not supported
+func buildRegex(regex string) (*re.Regexp, error) {
+	rc, err := re.CompilePOSIX(regex)
+	return rc, err
+}
+
+// walkFilteredDir - walk into a directory and its subdirectories and find files that match a regex
+func walkDirFiltered(directory string, regex re.Regexp) ([]string, error) {
+	var files []string
+	err := fp.Walk(directory,
+		func(path string, info os.FileInfo, err error) error {
+			if err != nil {
+				return err
+			}
+			if !info.IsDir() && regex.MatchString(path) {
+				fmt.Println(path)
+				files = append(files, path)
+			}
+			return err
+		})
+	return files, err
+}
+
+// getFilesFromDirectoryPath - wrapper calling `walkDirFiltered()`
+func getFilesFromDirectoryPath(directory string, regex re.Regexp) ([]string, error) {
+	files, err := walkDirFiltered(directory, regex)
+	return files, err
 }
 
 func main() {
 
+	// parse arguments
 	regex, directory, outputPath, err := parseArguments()
-
 	if err != nil {
 		log.Fatal("error while parsing args : ", err)
 	}
 
-	log.Printf("looking for file '%s' in '%s' ...", regex, directory)
+	// build regex from string
+	rc, err := buildRegex(regex)
+	if err != nil {
+		log.Fatal("error while compiling regex : '", regex, "'\nWARN: lookahead and lookbehind not implemented")
+	}
+
+	// deferencing Regexp pointer
+	rd := *rc
+
+	// walk into directory
+	log.Printf("looking for file '%s' in '%s' ...", rd.String(), directory)
+	files, err := getFilesFromDirectoryPath(directory, rd)
+
+	log.Printf("files found : %d", len(files))
 	log.Printf("files zipped in %s", outputPath)
 }