out_splunk: Extend retrying HTTP status code

408 and 429 also should be treated as retry.

Signed-off-by: Hiroshi Hatake <hiroshi@chronosphere.io>

plugins/out_splunk/splunk.c

@@ -768,8 +768,13 @@ static void cb_splunk_flush(struct flb_event_chunk *event_chunk,
  * them:
  *
  * https://docs.splunk.com/Documentation/Splunk/8.0.5/Data/TroubleshootHTTPEventCollector#Possible_error_codes
+ * From trouble shoot document on Splunk secure gateway,
+ * 408 and 429 should be also handled as try again:
+ *
+ * https://docs.splunk.com/Documentation/SecureGateway/3.5.15/Admin/TroubleshootGateway#Troubleshoot_error_codes
  */
- ret = (c->resp.status < 400 || c->resp.status >= 500) ?
+ ret = (c->resp.status < 400 || c->resp.status >= 500 ||
+ c->resp.status == 408 || c->resp.status == 429) ?
  FLB_RETRY : FLB_ERROR;