MXS-2219 Update datastructures instead of recreating them

The node infos of the Clustrix servers are now kept around and
and updated based upon changing conditions instead of regularly
being re-created.

Further, the server is now looked up by name only right after
having been created (and that only due to runtime_create_server()
currently being used).

The state of the dynamically created server is now updated directly
as a result of the health-check ping, while the state of the bootstrap
servers is updated during the tick()-call according to the monitor
"protocol".

server/modules/monitor/clustrixmon/clustrixmonitor.cc

@@ -13,6 +13,7 @@
 
 #include "clustrixmonitor.hh"
 #include <algorithm>
+#include <set>
 #include "../../../core/internal/config_runtime.hh"
 
 namespace http = mxb::http;
@@ -135,11 +136,14 @@ void ClustrixMonitor::fetch_cluster_nodes_from(MXS_MONITORED_SERVER& ms)
         {
             mxb_assert(mysql_field_count(ms.con) == 4);
 
-            vector<ClustrixNodeInfo> node_infos;
-            vector<string> health_urls;
-
             MYSQL_ROW row;
 
+            set<int> nids;
+            for_each(m_node_infos.begin(), m_node_infos.end(),
+                     [&nids](const pair<int, ClustrixNodeInfo>& element) {
+                         nids.insert(element.first);
+                     });
+
             while ((row = mysql_fetch_row(pResult)) != nullptr)
             {
                 if (row[0] && row[1])
@@ -150,20 +154,27 @@ void ClustrixMonitor::fetch_cluster_nodes_from(MXS_MONITORED_SERVER& ms)
                     int health_port = row[3] ? atoi(row[3]) : DEFAULT_HEALTH_PORT;
                     int health_check_threshold = m_config.health_check_threshold();
 
-                    string name = "Clustrix-Server-" + std::to_string(id);
+                    string name = "@Clustrix-Server-" + std::to_string(id);
 
-                    if (SERVER::find_by_unique_name(name) ||
+                    auto it = m_node_infos.find(id);
-			runtime_create_server(name.c_str(),
+
+                    if (it == m_node_infos.end())
+                    {
+                        mxb_assert(!SERVER::find_by_unique_name(name));
+
+			if (runtime_create_server(name.c_str(),
                                                   ip.c_str(),
                                                   std::to_string(mysql_port).c_str(),
                                                   "mariadbbackend",
                                                   "mysqlbackendauth",
                                                   false))
                         {
-                        node_infos.emplace_back(id, ip, mysql_port, health_port, health_check_threshold);
+                            SERVER* pServer = SERVER::find_by_unique_name(name);
+                            mxb_assert(pServer);
 
-                        string health_url = "http://" + ip + ":" + std::to_string(health_port);
+                            ClustrixNodeInfo info(id, ip, mysql_port, health_port, health_check_threshold, pServer);
-                        health_urls.push_back(health_url);
+
+                            m_node_infos.insert(make_pair(id, info));
                         }
                         else
                         {
@@ -173,14 +184,40 @@ void ClustrixMonitor::fetch_cluster_nodes_from(MXS_MONITORED_SERVER& ms)
                     }
                     else
                     {
-                    MXS_WARNING("Either nodeid and/or iface_ip is missing, "
+                        mxb_assert(SERVER::find_by_unique_name(name));
-                                "ignoring node.");
+
+                        auto it = nids.find(id);
+                        mxb_assert(it != nids.end());
+                        nids.erase(it);
+                    }
+                }
+                else
+                {
+                    MXS_WARNING("Either nodeid and/or iface_ip is missing, ignoring node.");
                 }
             }
 
             mysql_free_result(pResult);
 
-            m_node_infos.swap(node_infos);
+	    for_each(nids.begin(), nids.end(),
+		     [this](int nid) {
+		       auto it = m_node_infos.find(nid);
+		       mxb_assert(it != m_node_infos.end());
+
+		       ClustrixNodeInfo& info = it->second;
+		       info.deactivate_server();
+		       m_node_infos.erase(it);
+		     });
+
+            vector<string> health_urls;
+            for_each(m_node_infos.begin(), m_node_infos.end(),
+                     [&health_urls](const pair<int, ClustrixNodeInfo>& element) {
+                         const ClustrixNodeInfo& info = element.second;
+                         string url = "http://" + info.ip() + ":" + std::to_string(info.health_port());
+
+                         health_urls.push_back(url);
+                     });
+
             m_health_urls.swap(health_urls);
 
             m_last_cluster_check = now();
@@ -233,13 +270,16 @@ void ClustrixMonitor::update_server_statuses()
                  monitor_stash_current_status(&ms);
 
                  auto it = find_if(m_node_infos.begin(), m_node_infos.end(),
-                                   [&ms](const ClustrixNodeInfo& info) -> bool {
+                                   [&ms](const std::pair<int,ClustrixNodeInfo>& element) -> bool {
+                                       const ClustrixNodeInfo& info = element.second;
                                        return ms.server->address == info.ip();
                                    });
 
                  if (it != m_node_infos.end())
                  {
-                     if (it->is_running())
+                     const ClustrixNodeInfo& info = it->second;
+
+                     if (info.is_running())
                      {
                          monitor_set_pending_status(&ms, SERVER_RUNNING);
                      }
@@ -310,10 +350,10 @@ bool ClustrixMonitor::check_http(Call::action_t action)
             {
                 const vector<http::Result>& results = m_http.results();
 
-                for (size_t i = 0; i < results.size(); ++i)
+                auto it = m_node_infos.begin();
-                {
-                    const auto& result = results[i];
 
+                for_each(results.begin(), results.end(),
+                         [&it](const http::Result& result) {
                              bool running = false;
 
                              if (result.code == 200)
@@ -321,10 +361,12 @@ bool ClustrixMonitor::check_http(Call::action_t action)
                                  running = true;
                              }
 
-		    auto& node_info = m_node_infos[i];
+                             auto& node_info = it->second;
 
                              node_info.set_running(running);
-                }
+
+                             ++it;
+                         });
             }
             break;
 

server/modules/monitor/clustrixmon/clustrixmonitor.hh

@@ -13,6 +13,7 @@
 #pragma once
 
 #include "clustrixmon.hh"
+#include <map>
 #include <maxscale/monitor.hh>
 #include <maxbase/http.hh>
 #include "clustrixnodeinfo.hh"
@@ -87,7 +88,7 @@ private:
 private:
     Config                          m_config;
     std::vector<std::string>        m_config_servers;
-    std::vector<ClustrixNodeInfo> m_node_infos;
+    std::map<int, ClustrixNodeInfo> m_node_infos;
     std::vector<std::string>        m_health_urls;
     mxb::http::Async                m_http;
     uint32_t                        m_delayed_http_check_id { 0 };

server/modules/monitor/clustrixmon/clustrixnodeinfo.hh

@@ -24,13 +24,15 @@ public:
                      const std::string& ip,
                      int mysql_port,
                      int health_port,
-                     int health_check_threshold)
+                     int health_check_threshold,
+                     SERVER* pServer)
         : m_id(id)
         , m_ip(ip)
         , m_mysql_port(mysql_port)
         , m_health_port(health_port)
         , m_health_check_threshold(health_check_threshold)
         , m_nRunning(m_health_check_threshold)
+        , m_pServer(pServer)
     {
     }
 
@@ -64,15 +66,27 @@ public:
         if (running)
         {
             m_nRunning = m_health_check_threshold;
+
+            m_pServer->set_status(SERVER_RUNNING);
         }
         else
         {
             if (m_nRunning > 0)
             {
                 --m_nRunning;
+
+                if (m_nRunning == 0)
+                {
+                    m_pServer->clear_status(SERVER_RUNNING);
                 }
             }
         }
+    }
+
+    void deactivate_server()
+    {
+        m_pServer->is_active = false;
+    }
 
     std::string to_string() const
     {
@@ -93,6 +107,7 @@ private:
     int         m_health_port;
     int         m_health_check_threshold;
     int         m_nRunning;
+    SERVER*     m_pServer;
 };
 
 inline std::ostream& operator << (std::ostream& out, const ClustrixNodeInfo& x)