MEDIUM: http: do not report connection errors for second and further requests

In HTTP keep-alive, if we face a connection error to the server while sending
the request, the error should not be reported, and the client-side connection
should simply be closed, so that client knows it can retry. This can happen if
the server has too short a keep-alive timeout and quits at the same moment the
new request comes in.

diff --git a/src/proto_http.c b/src/proto_http.c
index f9554b422469196162f508a107b954584e82b2c4..721bc36beff5c1e8da82cf6b7003b63d7f38130b 100644 (file)
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -913,6 +913,8 @@ void http_perform_server_redirect(struct session *s, struct stream_interface *si
  * logs might explain incomplete retries. All others should avoid
  * being cumulated. It should normally not be possible to have multiple
  * aborts at once, but just in case, the first one in sequence is reported.
+ * Note that connection errors appearing on the second request of a keep-alive
+ * connection are not reported since this allows the client to retry.
  */
 void http_return_srv_error(struct session *s, struct stream_interface *si)
 {
@@ -923,7 +925,8 @@ void http_return_srv_error(struct session *s, struct stream_interface *si)
                                  503, http_error_message(s, HTTP_ERR_503));
        else if (err_type & SI_ET_CONN_ABRT)
                http_server_error(s, si, SN_ERR_CLICL, SN_FINST_C,
-                                 503, http_error_message(s, HTTP_ERR_503));
+                                 503, (s->txn.flags & TX_NOT_FIRST) ? NULL :
+                                 http_error_message(s, HTTP_ERR_503));
        else if (err_type & SI_ET_QUEUE_TO)
                http_server_error(s, si, SN_ERR_SRVTO, SN_FINST_Q,
                                  503, http_error_message(s, HTTP_ERR_503));
@@ -932,13 +935,16 @@ void http_return_srv_error(struct session *s, struct stream_interface *si)
                                  503, http_error_message(s, HTTP_ERR_503));
        else if (err_type & SI_ET_CONN_TO)
                http_server_error(s, si, SN_ERR_SRVTO, SN_FINST_C,
-                                 503, http_error_message(s, HTTP_ERR_503));
+                                 503, (s->txn.flags & TX_NOT_FIRST) ? NULL :
+                                 http_error_message(s, HTTP_ERR_503));
        else if (err_type & SI_ET_CONN_ERR)
                http_server_error(s, si, SN_ERR_SRVCL, SN_FINST_C,
-                                 503, http_error_message(s, HTTP_ERR_503));
+                                 503, (s->txn.flags & TX_NOT_FIRST) ? NULL :
+                                 http_error_message(s, HTTP_ERR_503));
        else if (err_type & SI_ET_CONN_RES)
                http_server_error(s, si, SN_ERR_RESOURCE, SN_FINST_C,
-                                 503, http_error_message(s, HTTP_ERR_503));
+                                 503, (s->txn.flags & TX_NOT_FIRST) ? NULL :
+                                 http_error_message(s, HTTP_ERR_503));
        else /* SI_ET_CONN_OTHER and others */
                http_server_error(s, si, SN_ERR_INTERNAL, SN_FINST_C,
                                  500, http_error_message(s, HTTP_ERR_500));
@@ -5136,6 +5142,8 @@ int http_wait_for_response(struct session *s, struct channel *rep, int an_bit)
                else if (rep->flags & CF_READ_ERROR) {
                        if (msg->err_pos >= 0)
                                http_capture_bad_message(&s->be->invalid_rep, s, msg, msg->msg_state, s->fe);
+                       else if (txn->flags & TX_NOT_FIRST)
+                               goto abort_keep_alive;
 
                        s->be->be_counters.failed_resp++;
                        if (objt_server(s->target)) {
@@ -5161,6 +5169,8 @@ int http_wait_for_response(struct session *s, struct channel *rep, int an_bit)
                else if (rep->flags & CF_READ_TIMEOUT) {
                        if (msg->err_pos >= 0)
                                http_capture_bad_message(&s->be->invalid_rep, s, msg, msg->msg_state, s->fe);
+                       else if (txn->flags & TX_NOT_FIRST)
+                               goto abort_keep_alive;
 
                        s->be->be_counters.failed_resp++;
                        if (objt_server(s->target)) {
@@ -5209,6 +5219,8 @@ int http_wait_for_response(struct session *s, struct channel *rep, int an_bit)
                else if (rep->flags & CF_SHUTR) {
                        if (msg->msg_state >= HTTP_MSG_RPVER || msg->err_pos >= 0)
                                http_capture_bad_message(&s->be->invalid_rep, s, msg, msg->msg_state, s->fe);
+                       else if (txn->flags & TX_NOT_FIRST)
+                               goto abort_keep_alive;
 
                        s->be->be_counters.failed_resp++;
                        if (objt_server(s->target)) {
@@ -5234,6 +5246,8 @@ int http_wait_for_response(struct session *s, struct channel *rep, int an_bit)
                else if (rep->flags & CF_WRITE_ERROR) {
                        if (msg->err_pos >= 0)
                                http_capture_bad_message(&s->be->invalid_rep, s, msg, msg->msg_state, s->fe);
+                       else if (txn->flags & TX_NOT_FIRST)
+                               goto abort_keep_alive;
 
                        s->be->be_counters.failed_resp++;
                        rep->analysers = 0;
@@ -5451,6 +5465,22 @@ skip_content_length:
        rep->analyse_exp = TICK_ETERNITY;
        channel_auto_close(rep);
        return 1;
+
+ abort_keep_alive:
+       /* A keep-alive request to the server failed on a network error.
+        * The client is required to retry. We need to close without returning
+        * any other information so that the client retries.
+        */
+       txn->status = 0;
+       rep->analysers = 0;
+       s->req->analysers = 0;
+       channel_auto_close(rep);
+       s->logs.logwait = 0;
+       s->logs.level = 0;
+       s->rep->flags &= ~CF_EXPECT_MORE; /* speed up sending a previous response */
+       bi_erase(rep);
+       stream_int_retnclose(rep->cons, NULL);
+       return 0;
 }
 
 /* This function performs all the processing enabled for the current response.