Templates factory to return clones (#343)

Author: yuri-tceretian

templates/factory.go

@@ -127,12 +127,12 @@ func (cf *CachedFactory) GetTemplate(kind Kind) (*Template, error) {
 	cf.mtx.Lock()
 	defer cf.mtx.Unlock()
 	if t, ok := cf.m[kind]; ok {
-		return t, nil
+		return t.Clone()
 	}
 	t, err := cf.factory.GetTemplate(kind)
 	if err != nil {
 		return nil, err
 	}
 	cf.m[kind] = t
-	return t, nil
+	return t.Clone()
 }

templates/factory_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"maps"
+	"strings"
 	"testing"
 	"time"
 
@@ -241,3 +242,30 @@ func TestFactoryWithTemplate(t *testing.T) {
 		require.ErrorIs(t, err, ErrInvalidKind)
 	})
 }
+
+func TestCachedTemplateFactory(t *testing.T) {
+	def := []TemplateDefinition{
+		{
+			Name:     "test",
+			Kind:     GrafanaKind,
+			Template: fmt.Sprintf(`{{ define "factory_test" }}TEST %s KIND{{ end }}`, GrafanaKind),
+		},
+	}
+	f, err := NewFactory(def, log.NewNopLogger(), "http://localhost")
+	require.NoError(t, err)
+	cached := NewCachedFactory(f)
+
+	for i := 0; i < 3; i++ { // check many times to ensure that clone it always return clean clone
+		tmpl, err := cached.GetTemplate(GrafanaKind)
+		require.NoError(t, err)
+
+		expanded, err := tmpl.ExecuteTextString(`{{ template "factory_test" . }}`, nil)
+		require.NoError(t, err)
+		require.Equal(t, `TEST Grafana KIND`, expanded)
+		// redefine template
+		require.NoError(t, tmpl.Parse(strings.NewReader(`{{ define "factory_test" }}TEST{{ end }}`)))
+		expanded, err = tmpl.ExecuteTextString(`{{ template "factory_test" . }}`, nil)
+		require.NoError(t, err)
+		require.Equal(t, `TEST`, expanded)
+	}
+}