rpc service generation (#26)

* add execute files

* add protoc-osx

* add rpc generation

* add rpc generation

* add: rpc template generation

* update usage

* fixed env prepare for project in go path

* optimize gomod cache

* add README.md

* format error

* reactor templatex.go

* remove waste code

tools/goctl/rpc/execx/execx.go

@@ -0,0 +1,34 @@
+package execx
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"os/exec"
+	"runtime"
+)
+
+func Run(arg string) (string, error) {
+	goos := runtime.GOOS
+	var cmd *exec.Cmd
+	switch goos {
+	case "darwin":
+		cmd = exec.Command("sh", "-c", arg)
+	case "windows":
+		cmd = exec.Command("cmd.exe", "/c", arg)
+	default:
+		return "", fmt.Errorf("unexpected os: %v", goos)
+	}
+	dtsout := new(bytes.Buffer)
+	stderr := new(bytes.Buffer)
+	cmd.Stdout = dtsout
+	cmd.Stderr = stderr
+	err := cmd.Run()
+	if err != nil {
+		if stderr.Len() > 0 {
+			return "", errors.New(stderr.String())
+		}
+		return "", err
+	}
+	return dtsout.String(), nil
+}