References lp:1216738, lp:1217567 - adjusted API accordingly.

Author: ayurchen

wsrep_api.h

@@ -88,10 +88,10 @@ typedef _Bool    wsrep_bool_t;    //!< should be the same as standard bool
 /*! undefined seqno */
 #define WSREP_SEQNO_UNDEFINED (-1)
 
-/*! wsrep status codes */
-typedef enum wsrep_status {
+/*! wsrep provider status codes */
+typedef enum wsrep_status
+{
     WSREP_OK = 0,          //!< success
-    WSREP_APPLIER_EXIT,    //!< success, applier marked to terminate
     WSREP_WARNING,         //!< minor warning, error logged
     WSREP_TRX_MISSING,     //!< transaction is not known by wsrep
     WSREP_TRX_FAIL,        //!< transaction aborted, server can continue
@@ -103,6 +103,19 @@ typedef enum wsrep_status {
     WSREP_NOT_IMPLEMENTED  //!< feature not implemented
 } wsrep_status_t;
 
+/*! wsrep callbacks status codes */
+typedef enum wsrep_cb_status
+{
+    WSREP_CB_RETURN  = -1, //!< success, thread wants to return from wsrep::recv() call
+    WSREP_CB_SUCCESS =  0, //!< success (as in "not critical failure")
+    WSREP_CB_FAILURE       //!< critical failure (consistency violation)
+    /* Technically, wsrep provider has no use for specific failure codes since
+     * there is nothing it can do about it but abort execution. Therefore any
+     * positive number shall indicate a critical failure. Optionally that value
+     * may be used by provider to come to a consensus about state consistency
+     * in a group of nodes. */
+} wsrep_cb_status_t;
+
 /*!
  * @brief log severity levels, passed as first argument to log handler
  */
@@ -130,7 +143,7 @@ typedef void (*wsrep_log_cb_t)(wsrep_log_level_t, const char *);
  * UUID type - for all unique IDs
  */
 typedef struct wsrep_uuid {
-    uint8_t uuid[16];
+    uint8_t data[16];
 } wsrep_uuid_t;
 
 /*! Undefined UUID */
@@ -234,8 +247,7 @@ typedef enum wsrep_view_status {
  * view of the group
  */
 typedef struct wsrep_view_info {
-    wsrep_uuid_t        uuid;      //!< global state UUID
-    wsrep_seqno_t       seqno;     //!< global state seqno
+    wsrep_gtid_t        state_id;  //!< global state ID
     wsrep_seqno_t       view;      //!< global view number
     wsrep_view_status_t status;    //!< view status
     wsrep_bool_t        state_gap; //!< gap between global and local states
@@ -282,13 +294,15 @@ typedef struct wsrep_view_info {
  * @param sst_req_len location to store SST request length or error code
  *                    value of 0 means no SST.
  */
-typedef void (*wsrep_view_cb_t) (void*                    app_ctx,
-                                 void*                    recv_ctx,
-                                 const wsrep_view_info_t* view,
-                                 const char*              state,
-                                 size_t                   state_len,
-                                 void**                   sst_req,
-                                 int*                     sst_req_len);
+typedef enum wsrep_cb_status (*wsrep_view_cb_t) (
+    void*                    app_ctx,
+    void*                    recv_ctx,
+    const wsrep_view_info_t* view,
+    const char*              state,
+    size_t                   state_len,
+    void**                   sst_req,
+    int*                     sst_req_len
+);
 
 /*!
  * @brief apply callback
@@ -306,11 +320,12 @@ typedef void (*wsrep_view_cb_t) (void*                    app_ctx,
  * @retval WSREP_NOT_IMPLEMENTED appl. does not support the writeset format
  * @retval WSREP_ERROR failed to apply the writeset
  */
-typedef enum wsrep_status (*wsrep_apply_cb_t) (
+typedef enum wsrep_cb_status (*wsrep_apply_cb_t) (
     void*                   recv_ctx,
     const void*             data,
     size_t                  size,
-    const wsrep_trx_meta_t* meta);
+    const wsrep_trx_meta_t* meta
+);
 
 /*!
  * @brief commit callback
@@ -325,10 +340,11 @@ typedef enum wsrep_status (*wsrep_apply_cb_t) (
  * @retval WSREP_OK
  * @retval WSREP_ERROR call failed
  */
-typedef enum wsrep_status (*wsrep_commit_cb_t) (
+typedef enum wsrep_cb_status (*wsrep_commit_cb_t) (
     void*                   recv_ctx,
     const wsrep_trx_meta_t* meta,
-    wsrep_bool_t            commit);
+    wsrep_bool_t            commit
+);
 
 /*!
  * @brief unordered callback
@@ -344,9 +360,9 @@ typedef enum wsrep_status (*wsrep_commit_cb_t) (
  * @retval WSREP_OK
  * @retval WSREP_ERROR call failed
  */
-typedef enum wsrep_status (*wsrep_unordered_cb_t) (void*       recv_ctx,
-                                                   const void* data,
-                                                   size_t      size);
+typedef enum wsrep_cb_status (*wsrep_unordered_cb_t) (void*       recv_ctx,
+                                                      const void* data,
+                                                      size_t      size);
 
 /*!
  * @brief a callback to donate state snapshot
@@ -361,8 +377,7 @@ typedef enum wsrep_status (*wsrep_unordered_cb_t) (void*       recv_ctx,
  * @param recv_ctx  receiver context
  * @param msg       state transfer request message
  * @param msg_len   state transfer request message length
- * @param uuid      current state uuid on this node
- * @param seqno     current state seqno on this node
+ * @param gtid      current state ID on this node
  * @param state     current wsrep internal state buffer
  * @param state_len current wsrep internal state buffer len
  * @param bypass    bypass snapshot transfer, only transfer uuid:seqno pair
@@ -372,8 +387,7 @@ typedef int (*wsrep_sst_donate_cb_t) (void*               app_ctx,
                                       void*               recv_ctx,
                                       const void*         msg,
                                       size_t              msg_len,
-                                      const wsrep_uuid_t* uuid,
-                                      wsrep_seqno_t       seqno,
+                                      const wsrep_gtid_t* state_id,
                                       const char*         state,
                                       size_t              state_len,
                                       wsrep_bool_t        bypass);
@@ -406,8 +420,7 @@ struct wsrep_init_args
     int         proto_ver;     //!< Max supported application protocol version
 
     /* Application initial state information. */
-    const wsrep_uuid_t* state_uuid;  //!< Application state sequence UUID
-    wsrep_seqno_t       state_seqno; //!< Applicaiton state sequence number
+    const wsrep_gtid_t* state_id;    //!< Application state ID
     const char*         state;       //!< Initial state for wsrep implementation
     size_t              state_len;   //!< Length of state buffer
 
@@ -840,29 +853,27 @@ struct wsrep_ {
    * @brief Signals to wsrep provider that state snapshot has been sent to
    *        joiner.
    *
-   * @param wsrep  provider handle
-   * @param uuid   sequence UUID (group UUID)
-   * @param seqno  sequence number or negative error code of the operation
+   * @param wsrep    provider handle
+   * @param state_id state ID
    */
     wsrep_status_t (*sst_sent)(wsrep_t*            wsrep,
-                               const wsrep_uuid_t* uuid,
-                               wsrep_seqno_t       seqno);
+                               const wsrep_gtid_t* state_id);
 
   /*!
    * @brief Signals to wsrep provider that new state snapshot has been received.
    *        May deadlock if called from sst_prepare_cb.
    *
    * @param wsrep     provider handle
-   * @param uuid      sequence UUID (group UUID)
-   * @param seqno     sequence number or negative error code of the operation
+   * @param state_id  state ID
    * @param state     initial state provided by SST donor
    * @param state_len length of state buffer
+   * @param rcode     0 or negative error code of the operation.
    */
     wsrep_status_t (*sst_received)(wsrep_t*            wsrep,
-                                   const wsrep_uuid_t* uuid,
-                                   wsrep_seqno_t       seqno,
+                                   const wsrep_gtid_t* state_id,
                                    const char*         state,
-                                   size_t              state_len);
+                                   size_t              state_len,
+                                   int                 rcode);
 
 
   /*!

wsrep_dummy.c

@@ -220,19 +220,18 @@ static wsrep_status_t dummy_preordered(
 
 static wsrep_status_t dummy_sst_sent(
     wsrep_t* w,
-    const wsrep_uuid_t* uuid   __attribute__((unused)),
-    wsrep_seqno_t       seqno  __attribute__((unused)))
+    const wsrep_gtid_t* state_id __attribute__((unused)))
 {
     WSREP_DBUG_ENTER(w);
     return WSREP_OK;
 }
 
 static wsrep_status_t dummy_sst_received(
     wsrep_t* w,
-    const wsrep_uuid_t* uuid      __attribute__((unused)),
-    const wsrep_seqno_t seqno     __attribute__((unused)),
+    const wsrep_gtid_t* state_id  __attribute__((unused)),
     const char*         state     __attribute__((unused)),
-    const size_t        state_len __attribute__((unused)))
+    const size_t        state_len __attribute__((unused)),
+    const int           rcode     __attribute__((unused)))
 {
     WSREP_DBUG_ENTER(w);
     return WSREP_OK;

wsrep_listener.c

@@ -50,18 +50,18 @@ logger_cb (wsrep_log_level_t level __attribute__((unused)), const char* msg)
  *  Each view change is the point where application may be pronounced out of
  *  sync with the current cluster view and need state transfer.
  *  It is guaranteed that no other callbacks are called concurrently with it. */
-static void
+static wsrep_cb_status_t
 view_cb (void*                    app_ctx   __attribute__((unused)),
          void*                    recv_ctx  __attribute__((unused)),
          const wsrep_view_info_t* view,
          const char*              state     __attribute__((unused)),
          size_t                   state_len __attribute__((unused)),
          void**                   sst_req,
-         ssize_t*                 sst_req_len)
+         int*                     sst_req_len)
 {
     printf ("New cluster membership view: %d nodes, my index is %d, "
             "global seqno: %lld\n",
-            view->memb_num, view->my_idx, (long long)view->seqno);
+            view->memb_num, view->my_idx, (long long)view->state_id.seqno);
 
     if (view->state_gap) /* we need to receive new state from the cluster */
     {
@@ -76,12 +76,14 @@ view_cb (void*                    app_ctx   __attribute__((unused)),
         else
             *sst_req_len = -ENOMEM;
     }
+
+    return WSREP_CB_SUCCESS;
 }
 
 /*! This is called to "apply" writeset.
  *  If writesets don't conflict on keys, it may be called concurrently to
  *  utilize several CPU cores. */
-static wsrep_status_t
+static wsrep_cb_status_t
 apply_cb (void*                   recv_ctx,
           const void*             ws_data __attribute__((unused)),
           size_t                  ws_size,
@@ -93,14 +95,14 @@ apply_cb (void*                   recv_ctx,
               "Got writeset %lld, size %zu", (long long)meta->gtid.seqno,
               ws_size);
 
-    return WSREP_OK;
+    return WSREP_CB_SUCCESS;
 }
 
 /*! This is called to "commit" or "rollback" previously applied writeset,
  *  depending on commit parameter.
  *  By default this callback is called synchronously in the order determined
  *  by seqno. */
-static wsrep_status_t
+static wsrep_cb_status_t
 commit_cb (void*                   recv_ctx,
            const wsrep_trx_meta_t* meta __attribute__((unused)),
            wsrep_bool_t            commit)
@@ -111,7 +113,7 @@ commit_cb (void*                   recv_ctx,
      * we don't need to worry about exclusive access to stdout. */
     if (commit) puts(ctx->msg);
 
-    return WSREP_OK;
+    return WSREP_CB_SUCCESS;
 }
 
 /* The following callbacks are stubs and not used in this example. */
@@ -120,8 +122,7 @@ sst_donate_cb (void*               app_ctx   __attribute__((unused)),
                void*               recv_ctx  __attribute__((unused)),
                const void*         msg       __attribute__((unused)),
                size_t              msg_len   __attribute__((unused)),
-               const wsrep_uuid_t* uuid      __attribute__((unused)),
-               wsrep_seqno_t       seqno     __attribute__((unused)),
+               const wsrep_gtid_t* state_id  __attribute__((unused)),
                const char*         state     __attribute__((unused)),
                size_t              state_len __attribute__((unused)),
                wsrep_bool_t        bypass    __attribute__((unused)))
@@ -176,6 +177,8 @@ int main (int argc, char* argv[])
         exit (EXIT_FAILURE);
     }
 
+    wsrep_gtid_t state_id = { WSREP_UUID_UNDEFINED, WSREP_SEQNO_UNDEFINED };
+
     /* wsrep provider initialization arguments */
     struct wsrep_init_args wsrep_args =
     {
@@ -188,8 +191,7 @@ int main (int argc, char* argv[])
         .options       = "",
         .proto_ver     = 127, // maximum supported application event protocol
 
-        .state_uuid    = &WSREP_UUID_UNDEFINED,
-        .state_seqno   = WSREP_SEQNO_UNDEFINED,
+        .state_id      = &state_id,
         .state         = NULL,
         .state_len     = 0,
 

wsrep_uuid.c

@@ -47,10 +47,10 @@ wsrep_uuid_scan (const char* str, size_t str_len, wsrep_uuid_t* uuid)
 
         if (isxdigit(str[uuid_len]) && isxdigit(str[uuid_len + 1])) {
             // got hex digit, scan another byte to uuid, increment uuid_offt
-            sscanf (str + uuid_len, "%2hhx", uuid->uuid + uuid_offt);
+            sscanf (str + uuid_len, "%2hhx", uuid->data + uuid_offt);
             uuid_len  += 2;
             uuid_offt += 1;
-            if (sizeof (uuid->uuid) == uuid_offt)
+            if (sizeof (uuid->data) == uuid_offt)
                 return uuid_len;
         }
         else {
@@ -71,7 +71,7 @@ int
 wsrep_uuid_print (const wsrep_uuid_t* uuid, char* str, size_t str_len)
 {
     if (str_len > 36) {
-        const unsigned char* u = uuid->uuid;
+        const unsigned char* u = uuid->data;
         return snprintf(str, str_len, "%02x%02x%02x%02x-%02x%02x-%02x%02x-"
                         "%02x%02x-%02x%02x%02x%02x%02x%02x",
                         u[ 0], u[ 1], u[ 2], u[ 3], u[ 4], u[ 5], u[ 6], u[ 7],
@@ -81,4 +81,3 @@ wsrep_uuid_print (const wsrep_uuid_t* uuid, char* str, size_t str_len)
         return -EMSGSIZE;
     }
 }
-