Merge pull request fluent#99 from dearonesama/fix-panic-struct

Fix panic when accessing unexported struct field

Author: tagomoris

fluent/fluent.go

@@ -212,13 +212,18 @@ func (f *Fluent) PostWithTime(tag string, tm time.Time, message interface{}) err
 fields := msgtype.NumField()
 for i := 0; i < fields; i++ {
 field := msgtype.Field(i)
+value := msg.FieldByIndex(field.Index)
+// ignore unexported fields
+if !value.CanInterface() {
+continue
+}
 name := field.Name
 if n1 := field.Tag.Get("msg"); n1 != "" {
 name = n1
 } else if n2 := field.Tag.Get("codec"); n2 != "" {
 name = n2
 }
-kv[name] = msg.FieldByIndex(field.Index).Interface()
+kv[name] = value.Interface()
 }
 return f.EncodeAndPostData(tag, tm, kv)
 }

fluent/fluent_test.go

@@ -436,6 +436,8 @@ func TestPostWithTime(t *testing.T) {
 
 _ = f.PostWithTime("tag_name", time.Unix(1482493046, 0), map[string]string{"foo": "bar"})
 _ = f.PostWithTime("tag_name", time.Unix(1482493050, 0), map[string]string{"fluentd": "is awesome"})
+_ = f.PostWithTime("tag_name", time.Unix(1634263200, 0),
+struct {Welcome string `msg:"welcome"`; cannot string}{"to use", "see me"})
 }()
 
 conn := d.waitForNextDialing(true)
@@ -446,6 +448,9 @@ func TestPostWithTime(t *testing.T) {
 assertReceived(t,
 conn.waitForNextWrite(true, ""),
 "[\"acme.tag_name\",1482493050,{\"fluentd\":\"is awesome\"},{}]")
+assertReceived(t,
+conn.waitForNextWrite(true, ""),
+"[\"acme.tag_name\",1634263200,{\"welcome\":\"to use\"},{}]")
 })
 }
 }