add more logs in cluster module

src/tendisplus/cluster/cluster_manager.cpp

@@ -377,10 +377,15 @@ uint32_t ClusterNode::delAllSlots() {
 bool ClusterNode::addSlave(std::shared_ptr<ClusterNode> slave) {
   std::lock_guard<myMutex> lk(_mutex);
   for (auto v : _slaves) {
-    if (v == slave)
+    if (v == slave) {
+      LOG(ERROR) << "node:" << getNodeName()
+                 << " already has slave:" << slave->getNodeName();
       return false;
+    }
   }
 
+  LOG(INFO) << "node:" << getNodeName()
+            << " add slave:" << slave->getNodeName();
   _slaves.emplace_back(std::move(slave));
   _flags |= CLUSTER_NODE_MIGRATE_TO;
   _numSlaves++;
@@ -392,6 +397,8 @@ bool ClusterNode::removeSlave(std::shared_ptr<ClusterNode> slave) {
 
   for (auto iter = _slaves.begin(); iter != _slaves.end();) {
     if (*iter == slave) {
+      LOG(WARNING) << "node:" << getNodeName()
+                   << " delete slave:" << slave->getNodeName();
       iter = _slaves.erase(iter);
       _numSlaves--;
 
@@ -557,6 +564,8 @@ void ClusterNode::setAsMaster() {
   std::lock_guard<myMutex> lk(_mutex);
   _flags &= ~CLUSTER_NODE_SLAVE;
   _flags |= CLUSTER_NODE_MASTER;
+  LOG(INFO) << "node:" << getNodeName() << " are master now. old master:"
+            << (_slaveOf ? _slaveOf->getNodeName() : "None");
   _slaveOf = nullptr;
 }
 
@@ -597,6 +606,8 @@ bool ClusterNode::clearNodeFailureIfNeeded(uint32_t timeout) {
 
 void ClusterNode::setMaster(std::shared_ptr<ClusterNode> master) {
   std::lock_guard<myMutex> lk(_mutex);
+  LOG(INFO) << "node:" << getNodeName() << " are slave now. old master:"
+            << (_slaveOf ? _slaveOf->getNodeName() : "None");
   _slaveOf = master;
 }