- Initialize member cluster ID only on connection to cluster and forget

it on disconnect.
 - Don't rely on own index from the view because the view may come from
   another member (IST/SST), instead always determine own index from own ID.

Refs codership/wsrep-lib#13

src/CMakeLists.txt

@@ -11,6 +11,7 @@ add_library(wsrep-lib
   logger.cpp
   provider.cpp
   seqno.cpp
+  view.cpp
   server_state.cpp
   transaction.cpp
   wsrep_provider_v26.cpp)

src/server_state.cpp

@@ -565,14 +565,38 @@ wsrep::server_state::causal_read(int timeout) const
     return provider_->causal_read(timeout);
 }
 
-void wsrep::server_state::on_connect(const wsrep::gtid& gtid)
+void wsrep::server_state::on_connect(const wsrep::view& view)
 {
+    // Sanity checks
+    if (id_.is_undefined() == false)
+    {
+        wsrep::log_warning() << "Unexpected connection in connected state. "
+                             << "Received view: " << view
+                             << "Previous ID: " << id_;
+        assert(0);
+    }
+
+    if (view.own_index() < 0 ||
+        size_t(view.own_index()) >= view.members().size())
+    {
+        std::ostringstream os;
+        os << "Invalid view on connect: own index out of range: " << view;
+        wsrep::log_error() << os.str();
+        assert(0);
+        throw wsrep::runtime_error(os.str());
+    }
+
+    id_ = view.members()[view.own_index()].id();
+
     wsrep::log_info() << "Server "
                       << name_
                       << " connected to cluster at position "
-                      << gtid;
+                      << view.state_id()
+                      << " with ID "
+                      << id_;
+
     wsrep::unique_lock<wsrep::mutex> lock(mutex_);
-    connected_gtid_ = gtid;
+    connected_gtid_ = view.state_id();
     state(lock, s_connected);
 }
 
@@ -599,22 +623,7 @@ void wsrep::server_state::on_view(const wsrep::view& view,
     if (view.status() == wsrep::view::primary)
     {
         wsrep::unique_lock<wsrep::mutex> lock(mutex_);
-        if (view.own_index() >= 0)
-        {
-            if (id_.is_undefined())
-            {
-                // No identifier was passed during server state initialization
-                // and the ID was generated by the provider.
-                id_ = view.members()[view.own_index()].id();
-            }
-            else
-            {
-                // Own identifier must not change between views.
-                // assert(id_ == view.members()[view.own_index()].id());
-            }
-        }
         assert(view.final() == false);
-
         //
         // Reached primary from connected state. This may mean the following
         //
@@ -703,6 +712,7 @@ void wsrep::server_state::on_view(const wsrep::view& view,
             {
                 close_transactions_at_disconnect(*high_priority_service);
             }
+            id_ = id::undefined();
             state(lock, s_disconnected);
         }
         else if (state_ != s_disconnecting)

src/view.cpp

@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2018 Codership Oy <info@codership.com>
+ *
+ * This file is part of wsrep-lib.
+ *
+ * Wsrep-lib 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-lib 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-lib.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "wsrep/view.hpp"
+
+void wsrep::view::print(std::ostream& os) const
+{
+    os << "  id: " << state_id() << "\n"
+       << "  status: " << status() << "\n"
+       << "  prococol_version: " << protocol_version() << "\n"
+       << "  final: " << final() << "\n"
+       << "  own_index: " << own_index() << "\n"
+       << "  members(" << members().size() << "):\n";
+
+    for (std::vector<wsrep::view::member>::const_iterator i(members().begin());
+         i != members().end(); ++i)
+    {
+        os << "\t" << (i - members().begin()) /* ordinal index */
+           << ") id: " << i->id()
+           << ", name: " << i->name() << "\n";
+    }
+}

src/wsrep_provider_v26.cpp

@@ -287,7 +287,8 @@ namespace
     {
         return capabilities;
     }
-    wsrep::view view_from_native(const wsrep_view_info& view_info)
+    wsrep::view view_from_native(const wsrep_view_info& view_info,
+                                 const wsrep::id& own_id)
     {
         std::vector<wsrep::view::member> members;
         for (int i(0); i < view_info.memb_num; ++i)
@@ -303,6 +304,25 @@ namespace
                         sizeof(view_info.members[i].incoming)));
             members.push_back(wsrep::view::member(id, name, incoming));
         }
+
+        int own_idx(-1);
+        if (own_id.is_undefined())
+        {
+            // If own ID is undefined, obtain it from the view. This is
+            // the case on the initial connect to cluster.
+            own_idx = view_info.my_idx;
+        }
+        else
+        {
+            // If the node has already obtained its ID from cluster,
+            // its position in the view (or lack thereof) must be determined
+            // by the ID.
+            for (size_t i(0); i < members.size(); ++i)
+            {
+                if (own_id == members[i].id()) { own_idx = i; break; }
+            }
+        }
+
         return wsrep::view(
             wsrep::gtid(
                 wsrep::id(view_info.state_id.uuid.data,
@@ -311,7 +331,7 @@ namespace
             wsrep::seqno(view_info.view),
             map_view_status_from_native(view_info.status),
             map_capabilities_from_native(view_info.capabilities),
-            view_info.my_idx,
+            own_idx,
             view_info.proto_ver,
             members);
     }
@@ -325,12 +345,14 @@ namespace
         const wsrep_view_info_t* view_info)
     {
         assert(app_ctx);
-        wsrep::view view(view_from_native(*view_info));
         wsrep::server_state& server_state(
             *reinterpret_cast<wsrep::server_state*>(app_ctx));
+        assert(server_state.id().is_undefined());
+        wsrep::view view(view_from_native(*view_info, server_state.id()));
+        assert(view.own_index() >= 0);
         try
         {
-            server_state.on_connect(view.state_id());
+            server_state.on_connect(view);
             return WSREP_CB_SUCCESS;
         }
         catch (const wsrep::runtime_error& e)
@@ -354,7 +376,7 @@ namespace
             reinterpret_cast<wsrep::high_priority_service*>(recv_ctx));
         try
         {
-            wsrep::view view(view_from_native(*view_info));
+            wsrep::view view(view_from_native(*view_info, server_state.id()));
             server_state.on_view(view, high_priority_service);
             return WSREP_CB_SUCCESS;
         }