@Override
public Set<NodeId> getAvailableNodes(NodeType type) {
Set<NodeId> result = Sets.newHashSet();
ZNode typeNode = rootNode.child(CoordinationUtil.nodeNameOf(type));
for (ZNode node : typeNode.children()) {
if (node.hasChild(CoordinationUtil.AVAILABLE_NODE_NAME)) {
result.add(NodeId.of(type, node.getShortPath()));
}
}
return result;
}
@Override
public void initialize() {
log.debug("Going to initialize required znode structure in zookeeper");
for (NodeType type : NodeType.values()) {
String child = CoordinationUtil.nodeNameOf(type);
rootNode.createChild(znode().withPath(child));
log.debug("Created node {}", child);
}
rootNode.createChild(znode().withPath(CoordinationUtil.STATUSES_NODE_NAME));
log.debug("Created node {}", CoordinationUtil.STATUSES_NODE_NAME);
log.debug("Successfully initialized");
}
@Override
public boolean canExecuteCommands(NodeId nodeId, Set<Qualifier<?>> qualifiers) {
ZNode typeNode = rootNode.child(CoordinationUtil.nodeNameOf(nodeId.getType()));
String identifier = nodeId.getIdentifier();
if (!typeNode.hasChild(identifier)) {
throw new CoordinatorException("Node with id " + nodeId + " is not found");
}
ZNode node = typeNode.child(identifier);
if (!node.hasChild(CoordinationUtil.AVAILABLE_NODE_NAME)) {
return false;
}
for (Qualifier<?> qualifier : qualifiers) {
if (!node.hasChild(nodeNameOf(qualifier))) {
return false;
}
}
return true;
}
@Override
public void registerNode(
NodeContext nodeContext, Set<Worker> workers, final StatusChangeListener listener)
throws CoordinatorException {
log.info("Going to register node {} with {} workers", nodeContext.getId(), workers.size());
ZNode typeNode = rootNode.child(CoordinationUtil.nodeNameOf(nodeContext.getId().getType()));
ZNode node = typeNode.createChild(znode().withPath(nodeContext.getId().getIdentifier()));
Set<CommandExecutor<?, ?>> executors = Sets.newHashSet();
Set<Qualifier<?>> qualifiers = Sets.newHashSet();
for (Worker worker : workers) {
for (CommandExecutor<?, ?> executor : worker.getExecutors()) {
Qualifier<?> qualifier = executor.getQualifier();
if (qualifiers.contains(qualifier)) {
throw new CoordinatorException(
"Executor for qualifier " + qualifier + " is already registered");
}
executors.add(executor);
}
}
for (CommandExecutor<?, ?> executor : executors) {
registerExecutor(nodeContext, executor, node);
}
rootNode.addNodeWatcher(
new Watcher() {
@Override
public void process(WatchedEvent event) {
if (event.getState() == Event.KeeperState.Disconnected) {
listener.onCoordinatorDisconnected();
}
if (event.getState() == Event.KeeperState.SyncConnected) {
listener.onCoordinatorConnected();
}
}
});
ZNode statuses = rootNode.child(CoordinationUtil.STATUSES_NODE_NAME);
statuses.createChild(znode().ephemeralSequential().withDataObject(nodeContext.getId()));
Lock lock = new ReentrantLock();
lock.lock();
try {
Collection<NodeId> nodeIds = Sets.newHashSet();
StatusWatcher statusWatcher = new StatusWatcher(statuses, lock, nodeIds, listener);
List<ZNode> nodes = statuses.children(statusWatcher);
for (ZNode zNode : nodes) {
nodeIds.add(zNode.getObject(NodeId.class));
}
} finally {
lock.unlock();
}
node.createChild(znode().withPath(CoordinationUtil.AVAILABLE_NODE_NAME));
}