Add "json" function

Author: md5

template.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"bytes"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
@@ -80,6 +81,15 @@ func hashSha1(input string) string {
 	return fmt.Sprintf("%x", h.Sum(nil))
 }
 
+func marshalJson(input interface{}) (string,error) {
+	var buf bytes.Buffer
+	enc := json.NewEncoder(&buf)
+	if err := enc.Encode(input); err != nil {
+		return "", err
+	}
+	return strings.TrimSuffix(buf.String(), "\n"), nil
+}
+
 func generateFile(config Config, containers Context) bool {
 	templatePath := config.Template
 	tmpl, err := template.New(filepath.Base(templatePath)).Funcs(template.FuncMap{
@@ -91,6 +101,7 @@ func generateFile(config Config, containers Context) bool {
 		"replace":      strings.Replace,
 		"dict":         dict,
 		"sha1":         hashSha1,
+		"json":         marshalJson,
 	}).ParseFiles(templatePath)
 	if err != nil {
 		log.Fatalf("unable to parse template: %s", err)

template_test.go

@@ -1,6 +1,10 @@
 package main
 
-import "testing"
+import (
+	"bytes"
+	"encoding/json"
+	"testing"
+)
 
 func TestContains(t *testing.T) {
 	env := map[string]string{
@@ -139,3 +143,43 @@ func TestSha1(t *testing.T) {
 		t.Fatal("Incorrect SHA1 sum")
 	}
 }
+
+func TestJson(t *testing.T) {
+	containers := []*RuntimeContainer{
+		&RuntimeContainer{
+			Env: map[string]string{
+				"VIRTUAL_HOST": "demo1.localhost",
+			},
+			ID: "1",
+		},
+		&RuntimeContainer{
+			Env: map[string]string{
+				"VIRTUAL_HOST": "demo1.localhost,demo3.localhost",
+			},
+			ID: "2",
+		},
+		&RuntimeContainer{
+			Env: map[string]string{
+				"VIRTUAL_HOST": "demo2.localhost",
+			},
+			ID: "3",
+		},
+	}
+	output, err := marshalJson(containers)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	buf := bytes.NewBufferString(output)
+	dec := json.NewDecoder(buf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var decoded []*RuntimeContainer
+	if err := dec.Decode(&decoded); err != nil {
+		t.Fatal(err)
+	}
+	if len(decoded) != len(containers) {
+		t.Fatal("Incorrect unmarshaled container count. Expected %d, got %d.", len(containers), len(decoded))
+	}
+}