[internal/utils] add EmbedFile function

utils.EmbedFile is a text file embed script for go:generate
to embed text files into generated golang source.

related to #830

internal/utils/file_embed.go

@@ -0,0 +1,64 @@
+package utils
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+
+	"github.com/iancoleman/strcase"
+)
+
+// EmbedFile Text file embed script for go:generate.
+// This script embeds a text file located at filePath into a string constant
+// named as constName defined in a golang source file located at the current
+// go:generate path.
+func EmbedFile(filePath string, constName string) {
+	// validate inputs
+	if _, err := os.Stat(filePath); os.IsNotExist(err) {
+		panic(fmt.Sprintf("File %s does not exist", filePath))
+	}
+
+	if strcase.ToLowerCamel(constName) != constName {
+		panic(fmt.Sprintf("constName %s is not in lower camel-case", constName))
+	}
+
+	// generate go file
+	var err error
+	fileName := filepath.Base(filePath)
+	generatedFileName := "generated_" + strcase.ToSnake(fileName) + ".go"
+	out, err := os.Create(generatedFileName)
+	if err != nil {
+		panic(err)
+	}
+
+	_, err = out.Write([]byte(fmt.Sprintf("package %s\n\nconst (\n", os.Getenv("GOPACKAGE"))))
+	if err != nil {
+		panic(err)
+	}
+
+	_, err = out.Write([]byte("\t" + constName + " = `"))
+	if err != nil {
+		panic(err)
+	}
+
+	f, err := os.Open(filePath)
+	if err != nil {
+		panic(err)
+	}
+
+	_, err = io.Copy(out, f)
+	if err != nil {
+		panic(err)
+	}
+
+	_, err = out.Write([]byte("`\n"))
+	if err != nil {
+		panic(err)
+	}
+
+	_, err = out.Write([]byte(")\n"))
+	if err != nil {
+		panic(err)
+	}
+}

scripts/wallet_embed_ini_files.go

@@ -1,30 +1,8 @@
 package main
 
-import (
-	"io"
-	"io/ioutil"
-	"os"
-	"path"
-	"strings"
+import "github.com/harmony-one/harmony/internal/utils"
 
-	"github.com/iancoleman/strcase"
-)
-
-// Reads all .ini files in the `.hmy` folder of root path
-// then encodes them as strings literals in `cmd/client/wallet/generated_ini.go`
+// Embed the default wallet.ini file into defaultWalletIni string literal constant
 func main() {
-	const root = "../../../"
-	hmy := path.Join(root, ".hmy")
-	fs, _ := ioutil.ReadDir(hmy)
-	out, _ := os.Create("generated_ini.go")
-	out.Write([]byte("package main\n\nconst (\n"))
-	for _, f := range fs {
-		if strings.HasSuffix(f.Name(), ".ini") {
-			out.Write([]byte("\t" + strcase.ToLowerCamel("default_"+strings.TrimSuffix(f.Name(), ".ini")+"_ini") + " = `"))
-			f, _ := os.Open(path.Join(hmy, f.Name()))
-			io.Copy(out, f)
-			out.Write([]byte("`\n"))
-		}
-	}
-	out.Write([]byte(")\n"))
+	utils.EmbedFile("../../../.hmy/wallet.ini", "defaultWalletIni")
 }