| /* |
| * 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.ratis.util; |
| |
| import org.apache.ratis.protocol.exceptions.AlreadyClosedException; |
| import org.apache.ratis.protocol.RaftPeer; |
| import org.apache.ratis.protocol.RaftPeerId; |
| import org.apache.ratis.util.function.CheckedFunction; |
| import org.apache.ratis.util.function.CheckedSupplier; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.io.Closeable; |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Objects; |
| import java.util.Optional; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| |
| /** A map from peer id to peer and its proxy. */ |
| public class PeerProxyMap<PROXY extends Closeable> implements RaftPeer.Add, Closeable { |
| public static final Logger LOG = LoggerFactory.getLogger(PeerProxyMap.class); |
| |
| /** Peer and its proxy. */ |
| private class PeerAndProxy { |
| private final RaftPeer peer; |
| private volatile PROXY proxy = null; |
| private final LifeCycle lifeCycle; |
| |
| PeerAndProxy(RaftPeer peer) { |
| this.peer = peer; |
| this.lifeCycle = new LifeCycle(peer); |
| } |
| |
| RaftPeer getPeer() { |
| return peer; |
| } |
| |
| PROXY getProxy() throws IOException { |
| if (proxy == null) { |
| synchronized (this) { |
| if (proxy == null) { |
| final LifeCycle.State current = lifeCycle.getCurrentState(); |
| if (current.isClosingOrClosed()) { |
| throw new AlreadyClosedException(name + " is already " + current); |
| } |
| lifeCycle.startAndTransition( |
| () -> proxy = createProxyImpl(peer), IOException.class); |
| } |
| } |
| } |
| return proxy; |
| } |
| |
| Optional<PROXY> setNullProxyAndClose() { |
| final PROXY p; |
| synchronized (this) { |
| p = proxy; |
| lifeCycle.checkStateAndClose(() -> proxy = null); |
| } |
| return Optional.ofNullable(p); |
| } |
| |
| @Override |
| public String toString() { |
| return peer.getId().toString(); |
| } |
| } |
| |
| private final String name; |
| private final Map<RaftPeerId, PeerAndProxy> peers = new ConcurrentHashMap<>(); |
| private final Object resetLock = new Object(); |
| |
| private final CheckedFunction<RaftPeer, PROXY, IOException> createProxy; |
| private final AtomicBoolean closed = new AtomicBoolean(); |
| |
| public PeerProxyMap(String name, CheckedFunction<RaftPeer, PROXY, IOException> createProxy) { |
| this.name = name; |
| this.createProxy = createProxy; |
| } |
| |
| public String getName() { |
| return name; |
| } |
| |
| private PROXY createProxyImpl(RaftPeer peer) throws IOException { |
| if (closed.get()) { |
| throw new AlreadyClosedException(name + ": Failed to create proxy for " + peer); |
| } |
| return createProxy.apply(peer); |
| } |
| |
| public PROXY getProxy(RaftPeerId id) throws IOException { |
| Objects.requireNonNull(id, "id == null"); |
| PeerAndProxy p = peers.get(id); |
| if (p == null) { |
| synchronized (resetLock) { |
| p = Objects.requireNonNull(peers.get(id), |
| () -> name + ": Server " + id + " not found: peers=" + peers.keySet()); |
| } |
| } |
| return p.getProxy(); |
| } |
| |
| @Override |
| public void addRaftPeers(Collection<RaftPeer> newPeers) { |
| for(RaftPeer p : newPeers) { |
| computeIfAbsent(p); |
| } |
| } |
| |
| /** |
| * This method is similar to {@link Map#computeIfAbsent(Object, java.util.function.Function)} |
| * except that this method does not require a mapping function. |
| * |
| * @param peer the peer for retrieving/building a proxy. |
| * @return a supplier of the proxy for the given peer. |
| */ |
| public CheckedSupplier<PROXY, IOException> computeIfAbsent(RaftPeer peer) { |
| final PeerAndProxy peerAndProxy = peers.computeIfAbsent(peer.getId(), k -> new PeerAndProxy(peer)); |
| return peerAndProxy::getProxy; |
| } |
| |
| public void resetProxy(RaftPeerId id) { |
| LOG.debug("{}: reset proxy for {}", name, id ); |
| final PeerAndProxy pp; |
| Optional<PROXY> optional = Optional.empty(); |
| synchronized (resetLock) { |
| pp = peers.remove(id); |
| if (pp != null) { |
| final RaftPeer peer = pp.getPeer(); |
| optional = pp.setNullProxyAndClose(); |
| computeIfAbsent(peer); |
| } |
| } |
| // close proxy without holding the reset lock |
| optional.map(proxy -> closeProxy(proxy, pp)) |
| .ifPresent(e -> LOG.warn("Failed to close the previous proxy", e)); |
| } |
| |
| /** @return true if the given throwable is handled; otherwise, the call is a no-op, return false. */ |
| public boolean handleException(RaftPeerId serverId, Throwable e, boolean reconnect) { |
| if (reconnect || IOUtils.shouldReconnect(e)) { |
| resetProxy(serverId); |
| return true; |
| } |
| return false; |
| } |
| |
| @Override |
| public void close() { |
| if (!closed.compareAndSet(false, true)) { |
| return; |
| } |
| |
| final List<IOException> exceptions = Collections.synchronizedList(new ArrayList<>()); |
| ConcurrentUtils.parallelForEachAsync(peers.values(), |
| pp -> pp.setNullProxyAndClose().map(proxy -> closeProxy(proxy, pp)).ifPresent(exceptions::add), |
| r -> new Thread(r).start() |
| ).join(); |
| |
| final int size = exceptions.size(); |
| if (size > 0) { |
| final Iterator<IOException> i = exceptions.iterator(); |
| final IOException e = new IOException(name + ": Failed to close proxy map", i.next()); |
| for(; i.hasNext(); ) { |
| e.addSuppressed(i.next()); |
| } |
| LOG.warn("{}: {} exception(s)", name, size, e); |
| } |
| } |
| |
| private IOException closeProxy(PROXY proxy, PeerAndProxy pp) { |
| try { |
| LOG.debug("{}: Closing proxy {} {} for peer {}", name, proxy.getClass().getSimpleName(), proxy, pp); |
| proxy.close(); |
| return null; |
| } catch (IOException e) { |
| return new IOException(name + ": Failed to close proxy for peer " + pp + ", " + proxy.getClass(), e); |
| } |
| } |
| } |