Add glob support

pkg/fs/realfs.go

@@ -19,6 +19,7 @@ package fs
 import (
 	"io/ioutil"
 	"os"
+	"path/filepath"
 )
 
 var _ FileSystem = realFS{}
@@ -46,6 +47,26 @@ func (realFS) Stat(name string) (os.FileInfo, error) { return os.Stat(name) }
 // ReadFile delegates to ioutil.ReadFile.
 func (realFS) ReadFile(name string) ([]byte, error) { return ioutil.ReadFile(name) }
 
+// ReadFiles use glob to find the matching files and then read content from all of them
+func (realFS) ReadFiles(name string) (map[string][]byte, error) {
+	files, err := filepath.Glob(name)
+	if err != nil || len(files) == 0 {
+		return nil, err
+	}
+
+	output := map[string][]byte{}
+	for _, file := range files {
+		bytes, err := ioutil.ReadFile(file)
+		if err != nil {
+			return nil, err
+		}
+		if bytes != nil {
+			output[file] = bytes
+		}
+	}
+	return output, nil
+}
+
 // WriteFile delegates to ioutil.WriteFile with read/write permissions.
 func (realFS) WriteFile(name string, c []byte) error {
 	return ioutil.WriteFile(name, c, 0666)