nghttpx: Don't cache time for logging

Update is done by main event loop which is stopped after graceful
shutdown is commenced, which means time is no longer update.  To avoid
this situation, we just avoid caching and get time for each logging.

src/shrpx.cc

@@ -421,19 +421,11 @@ void graceful_shutdown_signal_cb(struct ev_loop *loop, ev_signal *w,
 }
 } // namespace
 
-namespace {
-std::unique_ptr<std::string> generate_time() {
-  return util::make_unique<std::string>(
-      util::format_common_log(std::chrono::system_clock::now()));
-}
-} // namespace
-
 namespace {
 void refresh_cb(struct ev_loop *loop, ev_timer *w, int revents) {
   auto listener_handler = static_cast<ListenHandler *>(w->data);
   auto worker_stat = listener_handler->get_worker_stat();
 
-  mod_config()->cached_time = generate_time();
   // In multi threaded mode (get_config()->num_worker > 1), we have to
   // wait for event notification to workers to finish.
   if (get_config()->num_worker == 1 && worker_config->graceful_shutdown &&
@@ -698,7 +690,6 @@ void fill_default_config() {
   nghttp2_option_set_no_auto_window_update(mod_config()->http2_option, 1);
 
   mod_config()->tls_proto_mask = 0;
-  mod_config()->cached_time = generate_time();
   mod_config()->no_location_rewrite = false;
   mod_config()->argc = 0;
   mod_config()->argv = nullptr;

src/shrpx_config.h

@@ -169,7 +169,6 @@ struct Config {
   std::vector<std::pair<std::string, std::string>> add_response_headers;
   std::vector<unsigned char> alpn_prefs;
   std::vector<LogFragment> accesslog_format;
-  std::shared_ptr<std::string> cached_time;
   std::vector<DownstreamAddr> downstream_addrs;
   // binary form of http proxy host and port
   sockaddr_union downstream_http_proxy_addr;

src/shrpx_log.cc

@@ -122,16 +122,16 @@ Log::~Log() {
   char buf[4096];
   auto tty = wconf->errorlog_tty;
 
-  auto cached_time = get_config()->cached_time;
+  auto time_now = util::format_common_log(std::chrono::system_clock::now());
 
   if (severity_ == NOTICE) {
-    rv = snprintf(buf, sizeof(buf), "%s PID%d [%s%s%s] %s\n",
-                  cached_time->c_str(), get_config()->pid,
-                  tty ? SEVERITY_COLOR[severity_] : "", SEVERITY_STR[severity_],
-                  tty ? "\033[0m" : "", stream_.str().c_str());
+    rv = snprintf(buf, sizeof(buf), "%s PID%d [%s%s%s] %s\n", time_now.c_str(),
+                  get_config()->pid, tty ? SEVERITY_COLOR[severity_] : "",
+                  SEVERITY_STR[severity_], tty ? "\033[0m" : "",
+                  stream_.str().c_str());
   } else {
     rv = snprintf(buf, sizeof(buf), "%s PID%d [%s%s%s] %s%s:%d%s %s\n",
-                  cached_time->c_str(), get_config()->pid,
+                  time_now.c_str(), get_config()->pid,
                   tty ? SEVERITY_COLOR[severity_] : "", SEVERITY_STR[severity_],
                   tty ? "\033[0m" : "", tty ? "\033[1;30m" : "", filename_,
                   linenum_, tty ? "\033[0m" : "", stream_.str().c_str());