Handle server repurposing under a lock

By moving the repurposing of the servers under the global server lock, the
repurposing of a server and allocation of a new server behave in the same
way.

Also fixed the wrong error message on server creation failure referring to
invalid server relationships.

include/maxscale/server.h

@@ -132,7 +132,6 @@ typedef struct server
     int            persistmax;     /**< Maximum pool size actually achieved since startup */
     uint8_t        charset;        /**< Default server character set */
     bool           is_active;      /**< Server is active and has not been "destroyed" */
-    bool           created_online; /**< Whether this server was created after startup */
     bool           proxy_protocol; /**< Send proxy-protocol header to backend when connecting client sessions. */
 #if defined(SS_DEBUG)
     skygw_chk_t    server_chk_tail;
@@ -258,12 +257,16 @@ extern SERVER* server_alloc(const char *name, const char *address, unsigned shor
  * @param protocol      Protocol used by the server
  * @param authenticator The authenticator module of the server
  * @param auth_options  Options for the authenticator
- * @return Reusable SERVER or NULL if no servers matching the criteria were
+ * @param address       The network address of the new server
+ * @param port          The port of the new server
+ *
+ * @return Repurposed SERVER or NULL if no servers matching the criteria were
  * found
  * @see runtime_create_server
  */
-SERVER* server_find_destroyed(const char *name, const char *protocol,
+SERVER* server_repurpose_destroyed(const char *name, const char *protocol,
-                              const char *authenticator, const char *auth_options);
+                                   const char *authenticator, const char *auth_options,
+                                   const char *address, const char *port);
 /**
  * @brief Serialize a server to a file
  *

server/core/config_runtime.cc

@@ -161,36 +161,30 @@ bool runtime_create_server(const char *name, const char *address, const char *po
         }
 
         /** First check if this service has been created before */
-        SERVER *server = server_find_destroyed(name, protocol, authenticator,
+        SERVER *server = server_repurpose_destroyed(name, protocol, authenticator,
-                                               authenticator_options);
+                                                    authenticator_options,
+                                                    address, port);
 
         if (server)
         {
-            /** Found old server, replace network details with new ones and
+            MXS_DEBUG("Reusing server '%s'", name);
-             * reactivate it */
-            snprintf(server->name, sizeof(server->name), "%s", address);
-            server->port = atoi(port);
-            server->is_active = true;
-            rval = true;
         }
         else
         {
-            /**
+            MXS_DEBUG("Creating server '%s'", name);
-             * server_alloc will add the server to the global list of
-             * servers so we don't need to manually add it.
-             */
             server = server_alloc(name, address, atoi(port), protocol,
                                   authenticator, authenticator_options);
         }
 
         if (server && server_serialize(server))
         {
-            /** Mark that the server was created after startup */
+            rval = true;
-            server->created_online = true;
-
             MXS_NOTICE("Created server '%s' at %s:%u", server->unique_name,
                        server->name, server->port);
-            rval = true;
+        }
+        else
+        {
+            runtime_error("Failed to create server '%s', see error log for more details", name);
         }
     }
     else
@@ -1160,8 +1154,9 @@ SERVER* runtime_create_server_from_json(json_t* json)
 
         set<string> relations;
 
-        if (extract_relations(json, relations, server_relation_types, server_relation_is_valid) &&
+        if (extract_relations(json, relations, server_relation_types, server_relation_is_valid))
-            runtime_create_server(name, address, port.c_str(), protocol, authenticator, authenticator_options))
+        {
+            if (runtime_create_server(name, address, port.c_str(), protocol, authenticator, authenticator_options))
             {
                 rval = server_find_by_unique_name(name);
                 ss_dassert(rval);
@@ -1172,6 +1167,7 @@ SERVER* runtime_create_server_from_json(json_t* json)
                     rval = NULL;
                 }
             }
+        }
         else
         {
             runtime_error("Invalid relationships in request JSON");

server/core/server.cc

@@ -139,7 +139,6 @@ SERVER* server_alloc(const char *name, const char *address, unsigned short port,
     server->monuser[0] = '\0';
     server->monpw[0] = '\0';
     server->is_active = true;
-    server->created_online = false;
     server->charset = SERVER_DEFAULT_CHARSET;
     server->proxy_protocol = false;
 
@@ -1281,8 +1280,9 @@ bool server_serialize(const SERVER *server)
     return rval;
 }
 
-SERVER* server_find_destroyed(const char *name, const char *protocol,
+SERVER* server_repurpose_destroyed(const char *name, const char *protocol,
-                              const char *authenticator, const char *auth_options)
+                                   const char *authenticator, const char *auth_options,
+                                   const char *address, const char *port)
 {
     spinlock_acquire(&server_spin);
     SERVER *server = allServers;
@@ -1297,6 +1297,9 @@ SERVER* server_find_destroyed(const char *name, const char *protocol,
                 (auth_options && server->auth_options &&
                  strcmp(server->auth_options, auth_options) == 0))
             {
+                snprintf(server->name, sizeof(server->name), "%s", address);
+                server->port = atoi(port);
+                server->is_active = true;
                 break;
             }
         }