[pgexporter#64] Retrieving Server's Information

src/include/pgexporter.h

@@ -100,6 +100,8 @@ extern "C" {
 #define SERVER_QUERY_PRIMARY 1
 #define SERVER_QUERY_REPLICA 2
 
+#define SERVER_UNDERTERMINED_VERSION 0
+
 #define START_STATUS            0
 #define SEQUENCE_STATUS         1
 #define BLOCK_STATUS            2
@@ -198,6 +200,7 @@ struct server
    bool new;                           /**< Is the connection new */
    bool extension;                     /**< Is the pgexporter_ext extension installed */
    int state;                          /**< The state of the server */
+   char version;                       /**< The PostgreSQL version (char for minimum bytes)*/
 } __attribute__ ((aligned (64)));
 
 /** @struct

src/include/queries.h

@@ -86,6 +86,17 @@ pgexporter_query_get_functions(int server, struct query** query);
 int
 pgexporter_query_execute(int server, char* sql, char* tag, struct query** query);
 
+/**
+
+ * Extracts the server's version as a char (minimum integral data type), and sets
+ * the value of `config->servers[server].version` to it.
+ *
+ * @param server The server index in config
+ * @return 0 upon success, otherwise 1
+ */
+int
+pgexporter_server_version(int server);
+
 /**
  * Query for used disk space
  * @param server The server

src/libpgexporter/configuration.c

@@ -728,6 +728,7 @@ pgexporter_read_configuration(void* shm, char* filename)
 
    if (strlen(srv.name) > 0)
    {
+      srv.version = SERVER_UNDERTERMINED_VERSION;
       memcpy(&(config->servers[idx_server - 1]), &srv, sizeof(struct server));
    }
 

src/libpgexporter/queries.c

@@ -86,6 +86,7 @@ pgexporter_open_connections(void)
          {
             config->servers[server].new = true;
             pgexporter_server_info(server);
+            pgexporter_server_version(server);
          }
          else
          {
@@ -140,6 +141,31 @@ pgexporter_close_connections(void)
    }
 }
 
+int
+pgexporter_server_version(int server)
+{
+   struct query* q;
+   int ret;
+   struct configuration* config;
+
+   config = (struct configuration*)shmem;
+
+   ret = query_execute(server, "SELECT split_part(split_part(version(), ' ', 2), '.', 1);", "version", 1, NULL, &q);
+
+   if (q)
+   {
+      struct tuple* t = q->tuples;
+      if (t && t->data[0])
+      {
+         config->servers[server].version = atoi(t->data[0]);
+      }
+   }
+
+   pgexporter_free_query(q);
+
+   return ret;
+}
+
 int
 pgexporter_query_get_functions(int server, struct query** query)
 {