API extension to retrieve provider parameters

Author: sciascid

wsrep_config_service.h

@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2022 Codership Oy <[email protected]>
+ *
+ * This file is part of wsrep-API.
+ *
+ * Wsrep-API is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Wsrep-API is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with wsrep-API.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/** @file wsrep_config_service.h
+ *
+ * This file defines interface to retrieve a complete list of configuration
+ * parameters accepted by the provider.
+ * *
+ * The provider which is capable of using the service interface v1 must
+ * export the following functions:
+ *
+ * int wsrep_init_config_service_v1(wsrep_config_service_v1_t*)
+ * void wsrep_deinit_config_service_v1()
+ *
+ * which can be probed by the application.
+ *
+ */
+
+#ifndef WSREP_CONFIG_SERVICE_H
+#define WSREP_CONFIG_SERVICE_H
+
+#include "wsrep_api.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Flags to describe parameters.
+ * By default, a parameter is dynamic and of type string,
+ * unless flagged otherwise.
+ */
+#define WSREP_PARAM_DEPRECATED    (1 << 0)
+#define WSREP_PARAM_READONLY      (1 << 1)
+#define WSREP_PARAM_TYPE_BOOL     (1 << 2)
+#define WSREP_PARAM_TYPE_INTEGER  (1 << 3)
+#define WSREP_PARAM_TYPE_DOUBLE   (1 << 4)
+
+#define WSREP_PARAM_TYPE_MASK ( \
+    WSREP_PARAM_TYPE_BOOL     | \
+    WSREP_PARAM_TYPE_INTEGER  | \
+    WSREP_PARAM_TYPE_DOUBLE     \
+    )
+
+typedef struct wsrep_parameter
+{
+  int flags;
+  const char* name;
+  union {
+    bool as_bool;
+    int64_t as_integer;
+    double as_double;
+    const char* as_string;
+  } value;
+} wsrep_parameter_t;
+
+/**
+ * Callback called once for each parameter exposed by provider.
+ * The callback should return WSREP_OK on success. Any other
+ * return value causes get_parameters() to return WSREP_FATAL.
+ *
+ * @param p        parameter
+ * @param context  application context
+ *
+ * @return WSREP_OK on success, otherwise application failure
+ */
+typedef wsrep_status_t (*wsrep_get_parameters_cb) (const wsrep_parameter_t* p,
+                                                   void* context);
+
+/**
+ * Get configuration parameters exposed by the provider.
+ *
+ * @param wsrep    pointer to provider handle
+ * @param cb       function pointer for callback
+ * @param context  application context passed to callback
+ *
+ * @return WSREP_OK on success, WSREP_FATAL on failure
+ */
+typedef wsrep_status_t (*wsrep_get_parameters_fn) (wsrep_t* wsrep,
+                                                   wsrep_get_parameters_cb cb,
+                                                   void* context);
+
+/**
+ * Config service struct.
+ *
+ * A pointer to this struct must be passed to the call to
+ * wsrep_init_config_service_v1.
+ */
+typedef struct wsrep_config_service_v1_st {
+  wsrep_get_parameters_fn get_parameters;
+} wsrep_config_service_v1_t;
+
+#ifdef __cplusplus
+}
+#endif
+
+#define WSREP_CONFIG_SERVICE_INIT_FUNC_V1 "wsrep_init_config_service_v1"
+#define WSREP_CONFIG_SERVICE_DEINIT_FUNC_V1 "wsrep_deinit_config_service_v1"
+
+#endif /* WSREP_CONFIG_SERVICE */