Apache9 commented on code in PR #5631: URL: https://github.com/apache/hbase/pull/5631#discussion_r1478326465
########## hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionRegistryRpcStubHolder.java: ########## @@ -0,0 +1,212 @@ +/* + * 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.hadoop.hbase.client; + +import java.io.Closeable; +import java.io.IOException; +import java.util.ArrayList; +import java.util.Collection; +import java.util.Collections; +import java.util.List; +import java.util.Set; +import java.util.concurrent.CompletableFuture; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.hbase.HConstants; +import org.apache.hadoop.hbase.ServerName; +import org.apache.hadoop.hbase.ipc.HBaseRpcController; +import org.apache.hadoop.hbase.ipc.RpcClient; +import org.apache.hadoop.hbase.ipc.RpcClientFactory; +import org.apache.hadoop.hbase.ipc.RpcControllerFactory; +import org.apache.hadoop.hbase.security.User; +import org.apache.hadoop.hbase.util.IOExceptionSupplier; +import org.apache.yetus.audience.InterfaceAudience; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import org.apache.hbase.thirdparty.com.google.common.base.Preconditions; +import org.apache.hbase.thirdparty.com.google.common.collect.ImmutableMap; +import org.apache.hbase.thirdparty.com.google.protobuf.RpcCallback; +import org.apache.hbase.thirdparty.com.google.protobuf.RpcChannel; + +import org.apache.hadoop.hbase.shaded.protobuf.generated.RegistryProtos.ClientMetaService; +import org.apache.hadoop.hbase.shaded.protobuf.generated.RegistryProtos.ConnectionRegistryService; +import org.apache.hadoop.hbase.shaded.protobuf.generated.RegistryProtos.GetConnectionRegistryRequest; +import org.apache.hadoop.hbase.shaded.protobuf.generated.RegistryProtos.GetConnectionRegistryResponse; + +/** + * A class for creating {@link RpcClient} and related stubs used by + * {@link AbstractRpcBasedConnectionRegistry}. We need to connect to bootstrap nodes to get the + * cluster id first, before creating the final {@link RpcClient} and related stubs. + * <p> + * See HBASE-25051 for more details. + */ [email protected] +class ConnectionRegistryRpcStubHolder implements Closeable { + + private static final Logger LOG = LoggerFactory.getLogger(ConnectionRegistryRpcStubHolder.class); + + private final Configuration conf; + + // used for getting cluster id + private final Configuration noAuthConf; + + private final User user; + + private final RpcControllerFactory rpcControllerFactory; + + private final Set<ServerName> bootstrapNodes; + + private final int rpcTimeoutMs; + + private volatile ImmutableMap<ServerName, ClientMetaService.Interface> addr2Stub; + + private volatile RpcClient rpcClient; + + private CompletableFuture<ImmutableMap<ServerName, ClientMetaService.Interface>> addr2StubFuture; + + ConnectionRegistryRpcStubHolder(Configuration conf, User user, + RpcControllerFactory rpcControllerFactory, Set<ServerName> bootstrapNodes) { + this.conf = conf; + if (User.isHBaseSecurityEnabled(conf)) { + this.noAuthConf = new Configuration(conf); + this.noAuthConf.set(User.HBASE_SECURITY_CONF_KEY, "simple"); + } else { + this.noAuthConf = conf; + } + this.user = user; + this.rpcControllerFactory = rpcControllerFactory; + this.bootstrapNodes = Collections.unmodifiableSet(bootstrapNodes); + this.rpcTimeoutMs = (int) Math.min(Integer.MAX_VALUE, + conf.getLong(HConstants.HBASE_RPC_TIMEOUT_KEY, HConstants.DEFAULT_HBASE_RPC_TIMEOUT)); + } + + private ImmutableMap<ServerName, ClientMetaService.Interface> createStubs(RpcClient rpcClient, + Collection<ServerName> addrs) { + LOG.debug("Going to use new servers to create stubs: {}", addrs); + Preconditions.checkNotNull(addrs); + ImmutableMap.Builder<ServerName, ClientMetaService.Interface> builder = + ImmutableMap.builderWithExpectedSize(addrs.size()); + for (ServerName masterAddr : addrs) { + builder.put(masterAddr, + ClientMetaService.newStub(rpcClient.createRpcChannel(masterAddr, user, rpcTimeoutMs))); + } + return builder.build(); + } + + private void createStubsAndComplete(String clusterId, + CompletableFuture<ImmutableMap<ServerName, ClientMetaService.Interface>> future) { + RpcClient c = RpcClientFactory.createClient(conf, clusterId); + ImmutableMap<ServerName, ClientMetaService.Interface> m = createStubs(c, bootstrapNodes); + rpcClient = c; + addr2Stub = m; + future.complete(m); + } + + private void createStubs(List<ServerName> bootstrapServers, int index, + CompletableFuture<ImmutableMap<ServerName, ClientMetaService.Interface>> future) { + // use null cluster id here as we do not know the cluster id yet, we will fetch it through this + // rpc client and use it to create the final rpc client + RpcClient getConnectionRegistryRpcClient = RpcClientFactory.createClient(noAuthConf, null); + // user and rpcTimeout are both not important here, as we will not actually send any rpc calls + // out, only a preamble connection header, but if we pass null as user, there will be NPE in + // some code paths... + RpcChannel channel = + getConnectionRegistryRpcClient.createRpcChannel(bootstrapServers.get(index), user, 0); + ConnectionRegistryService.Interface stub = ConnectionRegistryService.newStub(channel); + HBaseRpcController controller = rpcControllerFactory.newController(); + stub.getConnectionRegistry(controller, GetConnectionRegistryRequest.getDefaultInstance(), + new RpcCallback<GetConnectionRegistryResponse>() { + + @Override + public void run(GetConnectionRegistryResponse resp) { + synchronized (ConnectionRegistryRpcStubHolder.this) { + addr2StubFuture = null; + if (controller.failed()) { + if (ConnectionUtils.isUnexpectedPreambleHeaderException(controller.getFailed())) { + // this means we have connected to an old server where it does not support passing + // cluster id through preamble connnection header, so we fallback to use null + // cluster id, which is the old behavior + LOG.debug("Failed to get connection registry info, should be an old server," + + " fallback to use null cluster id", controller.getFailed()); + createStubsAndComplete(null, future); + } else { + LOG.debug("Failed to get connection registry info", controller.getFailed()); + if (index == bootstrapServers.size() - 1) { + future.completeExceptionally(controller.getFailed()); + } else { + // try next bootstrap server + createStubs(bootstrapServers, index + 1, future); + } + } + } else { + LOG.debug("Got connection registry info: {}", resp); + String clusterId = resp.getClusterId(); + createStubsAndComplete(clusterId, future); + } + } + getConnectionRegistryRpcClient.close(); + } + }); + } + + private CompletableFuture<ImmutableMap<ServerName, ClientMetaService.Interface>> createStubs() { + CompletableFuture<ImmutableMap<ServerName, ClientMetaService.Interface>> future = + new CompletableFuture<>(); + List<ServerName> bootstrapServers = new ArrayList<ServerName>(bootstrapNodes); + Collections.shuffle(bootstrapServers); + createStubs(bootstrapServers, 0, future); + return future; + } + + CompletableFuture<ImmutableMap<ServerName, ClientMetaService.Interface>> getStubs() { + ImmutableMap<ServerName, ClientMetaService.Interface> s = this.addr2Stub; + if (s != null) { + return CompletableFuture.completedFuture(s); + } + synchronized (this) { + s = this.addr2Stub; + if (s != null) { + return CompletableFuture.completedFuture(s); + } + if (addr2StubFuture != null) { + return addr2StubFuture; + } + addr2StubFuture = createStubs(); + return addr2StubFuture; + } + } + + void refreshStubs(IOExceptionSupplier<Collection<ServerName>> fetchEndpoints) throws IOException { + // There is no actual call yet so we have not initialize the rpc client and related stubs yet, + // give up refreshing + if (addr2Stub == null) { + LOG.debug("Skip refreshing stubs as we have not initialized rpc client yet"); + return; + } + LOG.debug("Going to refresh stubs"); + assert rpcClient != null; + addr2Stub = createStubs(rpcClient, fetchEndpoints.get()); Review Comment: We do not need to synchronize here. The synchronization is for protecting the initialization of addr2Stub, and after initialization, addr2Stub will never be null, so we will never enter the synchronization block in getStubs method any more. And since addr2Stub is volatile, in refreshStubs, we just update the reference to addr2Stub at once, without changing its content, it is safe to not do any synchronization. Is this clear enough? Or we could introduce a initLock and synchronized on this object in getStubs method to make the logic more clear? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
