void MasterHandler::leadershipLoop() {
long maxSleep = 1000l*UPDATE_INTERVAL;
long interval = UPDATE_INTERVAL;
/**
* Algorithm:
* 1)Fetch list of files from backend
* 2)Check if there is any new change
* 3)Fetch list of avail nodes, their free space
* 4)Divide tasks among nodes
* 5)Clean all previous assignments
* 6)Publish assignments
*/
while(isRunning) {
//1)Fetch list of files from backend
Backend* backend = BackendManager::getActiveBackend();
if(backend == nullptr) {
LOG(DEBUG)<<"leadershipLoop(): No active backend.";
interval *= 10;
if(interval > maxSleep)
interval = maxSleep;
usleep(interval);
continue;
}
vector<BackendItem> backendList;
if(!backend->list(backendList)) {
LOG(ERROR)<<"leadershipLoop(): failed to retrive list of files from backend!";
interval *= 10;
if(interval > maxSleep)
interval = maxSleep;
usleep(interval);
continue;
}
//3)Fetch list of avail nodes, their free space
vector<ZooNode> globalView;
ZooHandler::getInstance().getGlobalView(globalView);
vector<ZooNode> globalFreeView = ZooHandler::getInstance().getGlobalFreeView();
//Fill GlobaView with globalfreeview
for(ZooNode& node:globalView) {
bool found = false;
for(ZooNode& fnode:globalFreeView){
if(fnode.hostName == node.hostName){
found = true;
node.freeSpace = fnode.freeSpace;
break;
}
}
if(!found){
LOG(ERROR)<<"\nCann't find free space for node:"<<node.hostName<<"\n";
continue;
}
}
//Check if there is any change in nodes(only checks freespace name and mac)
bool nodesChanged = false;
if(globalView.size()!=existingNodes.size()) {
//Get rid of already assigned ones because some of them might be dead
cleanAssignmentFolder();
nodesChanged = true;
}
else {
for(ZooNode &node:globalView)
if(!contains<ZooNode>(existingNodes,node)) {
nodesChanged = true;
break;
}
}
//2)Check if there is any new change or any change in nodes!
vector<BackendItem> oldAssignments = getExistingAssignments();
//cerr<<"oldAssignments:";printVector(oldAssignments);
if(oldAssignments.size() > 0)
removeDuplicates(backendList,oldAssignments);
if(nodesChanged) { //Get a copy in existing nodes
existingNodes.clear();
existingNodes.insert(existingNodes.end(),globalView.begin(),globalView.end());
}
//4)Divide tasks among nodes
//5)Clean all previous assignments
//6)Publish assignments
bool change = false;
if(backendList.size() || nodesChanged)
change = divideTaskAmongNodes(&backendList,globalView);
//Release Memory
backendList.clear();
//delete backendList;
//Release memory for GlobalView
for(ZooNode &node:globalView)
if(node.containedFiles)
delete node.containedFiles;
//Adaptive sleep
if(!change)
interval *= 10;
if(interval > maxSleep)
interval = maxSleep;
usleep(interval);
}
LOG(ERROR)<<"MASTERHANDLER LOOP DEAD!";
isRunning.store(false);
}
