added helper html template rendering utils

tools/template/renderer.go

@@ -0,0 +1,33 @@
+package template
+
+import (
+	"bytes"
+	"errors"
+	"html/template"
+)
+
+// Renderer defines a single parsed template.
+type Renderer struct {
+	template   *template.Template
+	parseError error
+}
+
+// Render executes the template with the specified data as the dot object
+// and returns the result as plain string.
+func (r *Renderer) Render(data any) (string, error) {
+	if r.parseError != nil {
+		return "", r.parseError
+	}
+
+	if r.template == nil {
+		return "", errors.New("invalid or nil template")
+	}
+
+	buf := new(bytes.Buffer)
+
+	if err := r.template.Execute(buf, data); err != nil {
+		return "", err
+	}
+
+	return buf.String(), nil
+}