ent/field: add default value for time

Reviewed By: alexsn

Differential Revision: D16890453

fbshipit-source-id: 362ae9e9666c523bdcce16503441565b6279ff08

schema/field/field.go

@@ -6,6 +6,7 @@ import (
 	"regexp"
 	"strconv"
 	"strings"
+	"time"
 )
 
 // Type is a field type.
@@ -482,6 +483,17 @@ func (b *timeBuilder) StructTag(s string) *timeBuilder {
 	return b
 }
 
+// Default sets the function that is applied to set default value
+// of the field on creation. For example:
+//
+//	field.Time("created_at").
+//		Default(time.Now)
+//
+func (b *timeBuilder) Default(f func() time.Time) *timeBuilder {
+	b.value = f
+	return b
+}
+
 // boolBuilder is the builder for boolean fields.
 type boolBuilder struct {
 	Field

schema/field/field_test.go

@@ -3,6 +3,7 @@ package field_test
 import (
 	"regexp"
 	"testing"
+	"time"
 
 	"fbc/ent"
 	"fbc/ent/schema/field"
@@ -75,10 +76,16 @@ func TestCharset(t *testing.T) {
 }
 
 func TestTime(t *testing.T) {
-	f := field.Time("created_at")
+	now := time.Now()
+	f := field.Time("created_at").
+		Default(func() time.Time {
+			return now
+		})
 	assert.Equal(t, "created_at", f.Name())
 	assert.Equal(t, field.TypeTime, f.Type())
 	assert.Equal(t, "time.Time", f.Type().String())
+	assert.NotNil(t, f.Value())
+	assert.Equal(t, now, f.Value().(func() time.Time)())
 }
 
 func TestField_Tag(t *testing.T) {