common: functions for template processing

common/template.go

+package common
+
+import (
+	"bytes"
+	"strconv"
+	"text/template"
+	"time"
+)
+
+type Template struct {
+	root *template.Template
+}
+
+func NewTemplate() (*Template, error) {
+	root := template.New("configTemplateRoot")
+	root.Funcs(template.FuncMap{
+		"timestamp": templateTimestamp,
+	})
+
+	result := &Template{
+		root: root,
+	}
+
+	return result, nil
+}
+
+func (t *Template) Process(s string, data interface{}) (string, error) {
+	tpl, err := t.root.New("tpl").Parse(s)
+	if err != nil {
+		return "", err
+	}
+
+	buf := new(bytes.Buffer)
+	if err := tpl.Execute(buf, data); err != nil {
+		return "", err
+	}
+
+	return buf.String(), nil
+}
+
+func templateTimestamp() string {
+	return strconv.FormatInt(time.Now().UTC().Unix(), 10)
+}

common/template_test.go

+package common
+
+import (
+	"math"
+	"strconv"
+	"testing"
+	"time"
+)
+
+func TestTemplateProcess(t *testing.T) {
+	tpl, err := NewTemplate()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	result, err := tpl.Process(`{{timestamp}}`, nil)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	val, err := strconv.ParseInt(result, 10, 64)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	currentTime := time.Now().UTC().Unix()
+	if math.Abs(float64(currentTime-val)) > 10 {
+		t.Fatalf("val: %d (current: %d)", val, currentTime)
+	}
+}