nghttpx: Log error in INFO level when frame cannot be sent

src/shrpx_http2_session.cc

@@ -1142,10 +1142,12 @@ int on_frame_not_send_callback(nghttp2_session *session,
                                const nghttp2_frame *frame, int lib_error_code,
                                void *user_data) {
   auto http2session = static_cast<Http2Session *>(user_data);
-  SSLOG(WARN, http2session) << "Failed to send control frame type="
-                            << static_cast<uint32_t>(frame->hd.type)
-                            << "lib_error_code=" << lib_error_code << ":"
-                            << nghttp2_strerror(lib_error_code);
+  if (LOG_ENABLED(INFO)) {
+    SSLOG(INFO, http2session) << "Failed to send control frame type="
+                              << static_cast<uint32_t>(frame->hd.type)
+                              << "lib_error_code=" << lib_error_code << ":"
+                              << nghttp2_strerror(lib_error_code);
+  }
   if (frame->hd.type == NGHTTP2_HEADERS &&
       frame->headers.cat == NGHTTP2_HCAT_REQUEST) {
     // To avoid stream hanging around, flag Downstream::MSG_RESET and

src/shrpx_http2_upstream.cc

@@ -553,10 +553,12 @@ int on_frame_not_send_callback(nghttp2_session *session,
                                const nghttp2_frame *frame, int lib_error_code,
                                void *user_data) {
   auto upstream = static_cast<Http2Upstream *>(user_data);
-  ULOG(WARN, upstream) << "Failed to send control frame type="
-                       << static_cast<uint32_t>(frame->hd.type)
-                       << ", lib_error_code=" << lib_error_code << ":"
-                       << nghttp2_strerror(lib_error_code);
+  if (LOG_ENABLED(INFO)) {
+    ULOG(INFO, upstream) << "Failed to send control frame type="
+                         << static_cast<uint32_t>(frame->hd.type)
+                         << ", lib_error_code=" << lib_error_code << ":"
+                         << nghttp2_strerror(lib_error_code);
+  }
   if (frame->hd.type == NGHTTP2_HEADERS &&
       frame->headers.cat == NGHTTP2_HCAT_RESPONSE &&
       lib_error_code != NGHTTP2_ERR_STREAM_CLOSED &&

src/shrpx_spdy_upstream.cc

@@ -343,9 +343,11 @@ void on_ctrl_not_send_callback(spdylay_session *session,
                                spdylay_frame_type type, spdylay_frame *frame,
                                int error_code, void *user_data) {
   auto upstream = static_cast<SpdyUpstream *>(user_data);
-  ULOG(WARN, upstream) << "Failed to send control frame type=" << type
-                       << ", error_code=" << error_code << ":"
-                       << spdylay_strerror(error_code);
+  if (LOG_ENABLED(INFO)) {
+    ULOG(INFO, upstream) << "Failed to send control frame type=" << type
+                         << ", error_code=" << error_code << ":"
+                         << spdylay_strerror(error_code);
+  }
   if (type == SPDYLAY_SYN_REPLY && error_code != SPDYLAY_ERR_STREAM_CLOSED &&
       error_code != SPDYLAY_ERR_STREAM_CLOSING) {
     // To avoid stream hanging around, issue RST_STREAM.