Move server disk space threshold setting to private Server-class

The setting can be read and written simultaneously and is protected with
a mutex.

The public SERVER-class is now abstract.

include/maxscale/server.hh

@@ -103,8 +103,9 @@ static uint64_t server_encode_version(const SERVER_VERSION* server_version)
  * the name of a protocol module that is loaded to implement the protocol
  * between the gateway and the server.
  */
-struct SERVER
+class SERVER
 {
+public:
     // Base settings
     char*          name;                            /**< Server config name */
     char           address[MAX_SERVER_ADDRESS_LEN]; /**< Server hostname/IP-address */
@@ -151,7 +152,31 @@ struct SERVER
                                                  * used
                                                  *   by rwsplit. TODO: Move to rwsplit */
     bool                   warn_ssl_not_enabled;/**< SSL not used for an SSL enabled server */
-    MxsDiskSpaceThreshold* disk_space_threshold;/**< Disk space thresholds */
+
+    virtual ~SERVER()
+    {
+    }
+
+    /**
+     * Check if server has disk space threshold settings.
+     *
+     * @return True if limits exist
+     */
+    virtual bool have_disk_space_limits() const = 0;
+
+    /**
+     * Get a copy of disk space limit settings.
+     *
+     * @return A copy of settings
+     */
+    virtual MxsDiskSpaceThreshold get_disk_space_limits() const = 0;
+
+    /**
+     * Set new disk space limits for the server.
+     *
+     * @param new_limits New limits
+     */
+    virtual void set_disk_space_limits(const MxsDiskSpaceThreshold& new_limits) = 0;
 };
 
 /**

server/core/internal/server.hh

@@ -36,6 +36,10 @@ public:
     {
     }
 
+    ~Server() override
+    {
+    }
+
     int response_time_num_samples() const
     {
         return m_response_time.num_samples();
@@ -51,10 +55,35 @@ public:
     static void dprintServer(DCB*, const Server*);
     static void dprintPersistentDCBs(DCB*, const Server*);
 
+    bool have_disk_space_limits() const override
+    {
+        std::lock_guard<std::mutex> guard(m_settings.lock);
+        return !m_settings.disk_space_limits.empty();
+    }
+
+    MxsDiskSpaceThreshold get_disk_space_limits() const override
+    {
+        std::lock_guard<std::mutex> guard(m_settings.lock);
+        return m_settings.disk_space_limits;
+    }
+
+    void set_disk_space_limits(const MxsDiskSpaceThreshold& new_limits) override
+    {
+        std::lock_guard<std::mutex> guard(m_settings.lock);
+        m_settings.disk_space_limits = new_limits;
+    }
+
     mutable std::mutex m_lock;
 
 private:
-    maxbase::EMAverage m_response_time;
+    struct Settings
+    {
+        mutable std::mutex lock;                 /**< Protects array-like settings from concurrent access */
+        MxsDiskSpaceThreshold disk_space_limits; /**< Disk space thresholds */
+    };
+
+    maxbase::EMAverage m_response_time;   /**< Response time calculations for this server */
+    Settings m_settings;                  /**< Server settings */
 };
 
 void server_free(Server* server);

server/core/monitor.cc

@@ -2623,12 +2623,11 @@ bool MonitorInstance::should_update_disk_space_status(const MXS_MONITORED_SERVER
 {
     bool should_check = false;
 
-    if (m_monitor->disk_space_check_interval
-        && (m_monitor->disk_space_threshold || pMs->server->disk_space_threshold)
-        && (pMs->disk_space_checked != -1))     // -1 means disabled
+    if ((m_monitor->disk_space_check_interval > 0)
+        && (pMs->disk_space_checked != -1) // -1 means disabled
+        && (m_monitor->disk_space_threshold || pMs->server->have_disk_space_limits()))
     {
         int64_t now = get_time_ms();
-
         if (now - pMs->disk_space_checked > m_monitor->disk_space_check_interval)
         {
             should_check = true;
@@ -2674,21 +2673,21 @@ void MonitorInstance::update_disk_space_status(MXS_MONITORED_SERVER* pMs)
 
     if (rv == 0)
     {
+        // Server-specific setting takes precedence.
+        MxsDiskSpaceThreshold dst = pMs->server->get_disk_space_limits();
+        if (dst.empty())
+        {
+            dst = *m_monitor->disk_space_threshold;
+        }
+
         bool disk_space_exhausted = false;
-
-        MxsDiskSpaceThreshold* pDst =
-            pMs->server->disk_space_threshold ?
-            pMs->server->disk_space_threshold : m_monitor->disk_space_threshold;
-        mxb_assert(pDst);
-
         int32_t star_max_percentage = -1;
-
         std::set<std::string> checked_paths;
 
-        for (auto i = pDst->begin(); i != pDst->end(); ++i)
+        for (const auto& dst_item : dst)
         {
-            string path = i->first;
-            int32_t max_percentage = i->second;
+            string path = dst_item.first;
+            int32_t max_percentage = dst_item.second;
 
             if (path == "*")
             {

server/core/server.cc

@@ -182,7 +182,6 @@ SERVER* server_alloc(const char* name, MXS_CONFIG_PARAMETER* params)
     server->master_id = -1;
     server->master_err_is_logged = false;
     server->warn_ssl_not_enabled = true;
-    server->disk_space_threshold = NULL;
 
     if (*monuser && *monpw)
     {
@@ -236,7 +235,6 @@ void server_free(Server* server)
         MXS_FREE(server->persistent);
     }
 
-    delete server->disk_space_threshold;
     delete server;
 }
 
@@ -1513,29 +1511,12 @@ json_t* server_list_to_json(const char* host)
 
 bool server_set_disk_space_threshold(SERVER* server, const char* disk_space_threshold)
 {
-    bool rv = false;
-
     MxsDiskSpaceThreshold dst;
-
-    rv = config_parse_disk_space_threshold(&dst, disk_space_threshold);
-
+    bool rv = config_parse_disk_space_threshold(&dst, disk_space_threshold);
     if (rv)
     {
-        if (!server->disk_space_threshold)
-        {
-            server->disk_space_threshold = new(std::nothrow) MxsDiskSpaceThreshold;
-        }
-
-        if (server->disk_space_threshold)
-        {
-            server->disk_space_threshold->swap(dst);
-        }
-        else
-        {
-            rv = false;
-        }
+        server->set_disk_space_limits(dst);
     }
-
     return rv;
 }
 

server/core/test/test_local_address.cc

@@ -16,6 +16,7 @@
 #include <iostream>
 #include <maxscale/config.hh>
 #include <maxscale/mysql_utils.hh>
+#include "../internal/server.hh"
 
 using namespace std;
 
@@ -78,9 +79,7 @@ int test(bool success, const char* zHost, const char* zUser, const char* zPasswo
     MXS_CONFIG* config = config_get_global_options();
     config->local_address = const_cast<char*>(zAddress);
 
-    SERVER server;
-    memset(&server, 0, sizeof(server));
-
+    Server server;
     strcpy(server.address, zHost);
     server.port = 3306;
 

server/modules/monitor/mariadbmon/test/test_cycle_find.cc

@@ -15,12 +15,13 @@
 #include <algorithm>
 #include <iostream>
 #include <numeric>
+#include <set>
 #include <string>
 #include <vector>
 #include <maxbase/log.hh>
 #include <maxbase/maxbase.hh>
 #include <maxscale/alloc.h>
-#include <set>
+#include "../../../../core/internal/server.hh"
 
 using std::string;
 using std::cout;
@@ -155,7 +156,7 @@ void MariaDBMonitor::Test::init_servers(int count)
 
     for (int i = 1; i < count + 1; i++)
     {
-        SERVER* base_server = new SERVER;   // Contents mostly undefined
+        auto base_server = new Server;   // Contents mostly undefined
         string server_name = create_servername(i);
         base_server->name = MXS_STRDUP(server_name.c_str());