/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.kafka.clients;
import java.util.HashMap;
import java.util.Map;
/**
* The state of our connection to each node in the cluster.
*
*/
final class ClusterConnectionStates {
private final long reconnectBackoffMs;
private final Map<String, NodeConnectionState> nodeState;
public ClusterConnectionStates(long reconnectBackoffMs) {
this.reconnectBackoffMs = reconnectBackoffMs;
this.nodeState = new HashMap<String, NodeConnectionState>();
}
/**
* Return true iff we can currently initiate a new connection. This will be the case if we are not
* connected and haven't been connected for at least the minimum reconnection backoff period.
* @param id the connection id to check
* @param now the current time in ms
* @return true if we can initiate a new connection
*/
public boolean canConnect(String id, long now) {
NodeConnectionState state = nodeState.get(id);
if (state == null)
return true;
else
return state.state == ConnectionState.DISCONNECTED && now - state.lastConnectAttemptMs >= this.reconnectBackoffMs;
}
/**
* Return true if we are disconnected from the given node and can't re-establish a connection yet.
* @param id the connection to check
* @param now the current time in ms
*/
public boolean isBlackedOut(String id, long now) {
NodeConnectionState state = nodeState.get(id);
if (state == null)
return false;
else
return state.state == ConnectionState.DISCONNECTED && now - state.lastConnectAttemptMs < this.reconnectBackoffMs;
}
/**
* Returns the number of milliseconds to wait, based on the connection state, before attempting to send data. When
* disconnected, this respects the reconnect backoff time. When connecting or connected, this handles slow/stalled
* connections.
* @param id the connection to check
* @param now the current time in ms
*/
public long connectionDelay(String id, long now) {
NodeConnectionState state = nodeState.get(id);
if (state == null) return 0;
long timeWaited = now - state.lastConnectAttemptMs;
if (state.state == ConnectionState.DISCONNECTED) {
return Math.max(this.reconnectBackoffMs - timeWaited, 0);
} else {
// When connecting or connected, we should be able to delay indefinitely since other events (connection or
// data acked) will cause a wakeup once data can be sent.
return Long.MAX_VALUE;
}
}
/**
* Return true if a specific connection establishment is currently underway
* @param id The id of the node to check
*/
public boolean isConnecting(String id) {
NodeConnectionState state = nodeState.get(id);
return state != null && state.state == ConnectionState.CONNECTING;
}
/**
* Enter the connecting state for the given connection.
* @param id the id of the connection
* @param now the current time
*/
public void connecting(String id, long now) {
nodeState.put(id, new NodeConnectionState(ConnectionState.CONNECTING, now));
}
/**
* Enter the disconnected state for the given node.
* @param id the connection we have disconnected
* @param now the current time
*/
public void disconnected(String id, long now) {
NodeConnectionState nodeState = nodeState(id);
nodeState.state = ConnectionState.DISCONNECTED;
nodeState.lastConnectAttemptMs = now;
}
/**
* Enter the checking_api_versions state for the given node.
* @param id the connection identifier
*/
public void checkingApiVersions(String id) {
NodeConnectionState nodeState = nodeState(id);
nodeState.state = ConnectionState.CHECKING_API_VERSIONS;
}
/**
* Enter the ready state for the given node.
* @param id the connection identifier
*/
public void ready(String id) {
NodeConnectionState nodeState = nodeState(id);
nodeState.state = ConnectionState.READY;
}
/**
* Return true if the connection is ready.
* @param id the connection identifier
*/
public boolean isReady(String id) {
NodeConnectionState state = nodeState.get(id);
return state != null && state.state == ConnectionState.READY;
}
/**
* Return true if the connection has been disconnected
* @param id The id of the node to check
*/
public boolean isDisconnected(String id) {
NodeConnectionState state = nodeState.get(id);
return state != null && state.state == ConnectionState.DISCONNECTED;
}
/**
* Remove the given node from the tracked connection states. The main difference between this and `disconnected`
* is the impact on `connectionDelay`: it will be 0 after this call whereas `reconnectBackoffMs` will be taken
* into account after `disconnected` is called.
*
* @param id the connection to remove
*/
public void remove(String id) {
nodeState.remove(id);
}
/**
* Get the state of a given connection.
* @param id the id of the connection
* @return the state of our connection
*/
public ConnectionState connectionState(String id) {
return nodeState(id).state;
}
/**
* Get the state of a given node.
* @param id the connection to fetch the state for
*/
private NodeConnectionState nodeState(String id) {
NodeConnectionState state = this.nodeState.get(id);
if (state == null)
throw new IllegalStateException("No entry found for connection " + id);
return state;
}
/**
* The state of our connection to a node.
*/
private static class NodeConnectionState {
ConnectionState state;
long lastConnectAttemptMs;
public NodeConnectionState(ConnectionState state, long lastConnectAttempt) {
this.state = state;
this.lastConnectAttemptMs = lastConnectAttempt;
}
public String toString() {
return "NodeState(" + state + ", " + lastConnectAttemptMs + ")";
}
}
}