Support JSON and template format with nomad CLI

command/data_format.go

@@ -0,0 +1,58 @@
+package command
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"text/template"
+)
+
+//DataFormatter is a transformer of the data.
+type DataFormatter interface {
+	// TransformData should return transformed string data.
+	TransformData(interface{}) (string, error)
+}
+
+// DataFormat returns the data formatter specified format.
+func DataFormat(format, tmpl string) (DataFormatter, error) {
+	switch format {
+	case "json":
+		return &JSONFormat{}, nil
+	case "template":
+		return &TemplateFormat{tmpl}, nil
+	}
+	return nil, fmt.Errorf("Unsupported format is specified.")
+}
+
+type JSONFormat struct {
+}
+
+// TransformData returns JSON format string data.
+func (p *JSONFormat) TransformData(data interface{}) (string, error) {
+	out, err := json.MarshalIndent(&data, "", "    ")
+	if err != nil {
+		return "", err
+	}
+
+	return string(out), nil
+}
+
+type TemplateFormat struct {
+	tmpl string
+}
+
+// TransformData returns template format string data.
+func (p *TemplateFormat) TransformData(data interface{}) (string, error) {
+	var out io.Writer = new(bytes.Buffer)
+	if len(p.tmpl) == 0 {
+		return "", fmt.Errorf("template needs to be specified the golang templates.")
+	}
+
+	t := template.Must(template.New("format").Parse(p.tmpl))
+	err := t.Execute(out, data)
+	if err != nil {
+		return "", err
+	}
+	return fmt.Sprint(out), nil
+}