MINOR: server: implement srv_set_stopped()

This function was extracted from check_set_server_down(). In only
manipulates the server state and does not consider the health checks
at all, nor does it modify their status. It takes a reason message to
report in logs, however it passes NULL when recursing through the
trackers chain.

For now the function is not used, but the goal is to split health
checks status from server status and to be able to change a server's
state regardless of health checks statuses.

include/proto/server.h

@@ -126,6 +126,16 @@ void srv_shutdown_backup_sessions(struct proxy *px, int why);
  */
 void srv_append_status(struct chunk *msg, struct server *s, const char *reason, int xferred, int forced);
 
+/* Marks server <s> down, regardless of its checks' statuses, notifies by all
+ * available means, recounts the remaining servers on the proxy and transfers
+ * queued sessions whenever possible to other servers. It automatically
+ * recomputes the number of servers, but not the map. Maintenance servers are
+ * ignored. It reports <reason> if non-null as the reason for going down. Note
+ * that it makes use of the trash to build the log strings, so <reason> must
+ * not be placed there.
+ */
+void srv_set_stopped(struct server *s, const char *reason);
+
 /* Puts server <s> into maintenance mode, and propagate that status down to all
  * tracking servers. This does the same action as the CLI's "disable server x".
  * A log is emitted for all servers that were not yet in maintenance mode.

src/server.c

@@ -217,6 +217,57 @@ void srv_append_status(struct chunk *msg, struct server *s, const char *reason,
 	}
 }
 
+/* Marks server <s> down, regardless of its checks' statuses, notifies by all
+ * available means, recounts the remaining servers on the proxy and transfers
+ * queued sessions whenever possible to other servers. It automatically
+ * recomputes the number of servers, but not the map. Maintenance servers are
+ * ignored. It reports <reason> if non-null as the reason for going down. Note
+ * that it makes use of the trash to build the log strings, so <reason> must
+ * not be placed there.
+ */
+void srv_set_stopped(struct server *s, const char *reason)
+{
+	struct server *srv;
+	int prev_srv_count = s->proxy->srv_bck + s->proxy->srv_act;
+	int srv_was_stopping = (s->state == SRV_ST_STOPPING);
+	int xferred;
+
+	if ((s->admin & SRV_ADMF_MAINT) || s->state == SRV_ST_STOPPED)
+		return;
+
+	s->last_change = now.tv_sec;
+	s->state = SRV_ST_STOPPED;
+	if (s->proxy->lbprm.set_server_status_down)
+		s->proxy->lbprm.set_server_status_down(s);
+
+	if (s->onmarkeddown & HANA_ONMARKEDDOWN_SHUTDOWNSESSIONS)
+		srv_shutdown_sessions(s, SN_ERR_DOWN);
+
+	/* we might have sessions queued on this server and waiting for
+	 * a connection. Those which are redispatchable will be queued
+	 * to another server or to the proxy itself.
+	 */
+	xferred = pendconn_redistribute(s);
+
+	chunk_printf(&trash,
+	             "%sServer %s/%s is DOWN", s->flags & SRV_F_BACKUP ? "Backup " : "",
+	             s->proxy->id, s->id);
+
+	srv_append_status(&trash, s, reason, xferred, 0);
+	Warning("%s.\n", trash.str);
+
+	/* we don't send an alert if the server was previously paused */
+	send_log(s->proxy, srv_was_stopping ? LOG_NOTICE : LOG_ALERT, "%s.\n", trash.str);
+
+	if (prev_srv_count && s->proxy->srv_bck == 0 && s->proxy->srv_act == 0)
+		set_backend_down(s->proxy);
+
+	s->counters.down_trans++;
+
+	for (srv = s->trackers; srv; srv = srv->tracknext)
+		srv_set_stopped(srv, NULL);
+}
+
 /* Puts server <s> into maintenance mode, and propagate that status down to all
  * tracking servers. This does the same action as the CLI's "disable server x".
  * A log is emitted for all servers that were not yet in maintenance mode.