/*
 * Copyright 2008-present MongoDB, Inc.
 *
 * Licensed 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 com.mongodb.client.internal;

import com.mongodb.ClientSessionOptions;
import com.mongodb.MongoClientException;
import com.mongodb.MongoCredential;
import com.mongodb.MongoException;
import com.mongodb.MongoInternalException;
import com.mongodb.MongoQueryException;
import com.mongodb.MongoSocketException;
import com.mongodb.MongoTimeoutException;
import com.mongodb.ReadConcern;
import com.mongodb.ReadPreference;
import com.mongodb.ServerAddress;
import com.mongodb.TransactionOptions;
import com.mongodb.WriteConcern;
import com.mongodb.binding.ClusterBinding;
import com.mongodb.binding.ReadBinding;
import com.mongodb.binding.ReadWriteBinding;
import com.mongodb.binding.WriteBinding;
import com.mongodb.client.ClientSession;
import com.mongodb.connection.Cluster;
import com.mongodb.connection.ClusterConnectionMode;
import com.mongodb.connection.ClusterDescription;
import com.mongodb.connection.ServerDescription;
import com.mongodb.internal.binding.ClusterAwareReadWriteBinding;
import com.mongodb.internal.session.ServerSessionPool;
import com.mongodb.lang.Nullable;
import com.mongodb.operation.ReadOperation;
import com.mongodb.operation.WriteOperation;
import com.mongodb.selector.ServerSelector;
import org.bson.codecs.configuration.CodecRegistry;

import java.util.ArrayList;
import java.util.List;

import static com.mongodb.MongoException.TRANSIENT_TRANSACTION_ERROR_LABEL;
import static com.mongodb.MongoException.UNKNOWN_TRANSACTION_COMMIT_RESULT_LABEL;
import static com.mongodb.ReadPreference.primary;
import static com.mongodb.assertions.Assertions.isTrue;
import static com.mongodb.assertions.Assertions.notNull;

This class is not part of the public API and may be removed or changed at any time.
/** * This class is not part of the public API and may be removed or changed at any time. */
public class MongoClientDelegate { private final Cluster cluster; private final ServerSessionPool serverSessionPool; private final List<MongoCredential> credentialList; private final Object originator; private final OperationExecutor operationExecutor; private final Crypt crypt; private final CodecRegistry codecRegistry; public MongoClientDelegate(final Cluster cluster, final CodecRegistry codecRegistry, final List<MongoCredential> credentialList, final Object originator, @Nullable final Crypt crypt) { this(cluster, codecRegistry, credentialList, originator, null, crypt); } MongoClientDelegate(final Cluster cluster, final CodecRegistry codecRegistry, final List<MongoCredential> credentialList, final Object originator, @Nullable final OperationExecutor operationExecutor, @Nullable final Crypt crypt) { this.cluster = cluster; this.codecRegistry = codecRegistry; this.serverSessionPool = new ServerSessionPool(cluster); this.credentialList = credentialList; this.originator = originator; this.operationExecutor = operationExecutor == null ? new DelegateOperationExecutor() : operationExecutor; this.crypt = crypt; } public OperationExecutor getOperationExecutor() { return operationExecutor; } @Nullable public ClientSession createClientSession(final ClientSessionOptions options, final ReadConcern readConcern, final WriteConcern writeConcern, final ReadPreference readPreference) { notNull("readConcern", readConcern); notNull("writeConcern", writeConcern); notNull("readPreference", readPreference); if (credentialList.size() > 1) { return null; } ClusterDescription connectedClusterDescription = getConnectedClusterDescription(); if (connectedClusterDescription.getLogicalSessionTimeoutMinutes() == null) { return null; } else { ClientSessionOptions mergedOptions = ClientSessionOptions.builder(options) .defaultTransactionOptions( TransactionOptions.merge( options.getDefaultTransactionOptions(), TransactionOptions.builder() .readConcern(readConcern) .writeConcern(writeConcern) .readPreference(readPreference) .build())) .build(); return new ClientSessionImpl(serverSessionPool, originator, mergedOptions, this); } } public List<ServerAddress> getServerAddressList() { List<ServerAddress> serverAddresses = new ArrayList<ServerAddress>(); for (final ServerDescription cur : cluster.getDescription().getServerDescriptions()) { serverAddresses.add(cur.getAddress()); } return serverAddresses; } public void close() { if (crypt != null) { crypt.close(); } serverSessionPool.close(); cluster.close(); } public Cluster getCluster() { return cluster; } public CodecRegistry getCodecRegistry() { return codecRegistry; } public ServerSessionPool getServerSessionPool() { return serverSessionPool; } private ClusterDescription getConnectedClusterDescription() { ClusterDescription clusterDescription = cluster.getDescription(); if (getServerDescriptionListToConsiderForSessionSupport(clusterDescription).isEmpty()) { cluster.selectServer(new ServerSelector() { @Override public List<ServerDescription> select(final ClusterDescription clusterDescription) { return getServerDescriptionListToConsiderForSessionSupport(clusterDescription); } }); clusterDescription = cluster.getDescription(); } return clusterDescription; } @SuppressWarnings("deprecation") private List<ServerDescription> getServerDescriptionListToConsiderForSessionSupport(final ClusterDescription clusterDescription) { if (clusterDescription.getConnectionMode() == ClusterConnectionMode.SINGLE) { return clusterDescription.getAny(); } else { return clusterDescription.getAnyPrimaryOrSecondary(); } } private class DelegateOperationExecutor implements OperationExecutor { @Override public <T> T execute(final ReadOperation<T> operation, final ReadPreference readPreference, final ReadConcern readConcern) { return execute(operation, readPreference, readConcern, null); } @Override public <T> T execute(final WriteOperation<T> operation, final ReadConcern readConcern) { return execute(operation, readConcern, null); } @Override public <T> T execute(final ReadOperation<T> operation, final ReadPreference readPreference, final ReadConcern readConcern, @Nullable final ClientSession session) { ClientSession actualClientSession = getClientSession(session); ReadBinding binding = getReadBinding(readPreference, readConcern, actualClientSession, session == null && actualClientSession != null); try { if (session != null && session.hasActiveTransaction() && !binding.getReadPreference().equals(primary())) { throw new MongoClientException("Read preference in a transaction must be primary"); } return operation.execute(binding); } catch (MongoException e) { labelException(session, e); unpinServerAddressOnTransientTransactionError(session, e); throw e; } finally { binding.release(); } } @Override public <T> T execute(final WriteOperation<T> operation, final ReadConcern readConcern, @Nullable final ClientSession session) { ClientSession actualClientSession = getClientSession(session); WriteBinding binding = getWriteBinding(readConcern, actualClientSession, session == null && actualClientSession != null); try { return operation.execute(binding); } catch (MongoException e) { labelException(session, e); unpinServerAddressOnTransientTransactionError(session, e); throw e; } finally { binding.release(); } } WriteBinding getWriteBinding(final ReadConcern readConcern, @Nullable final ClientSession session, final boolean ownsSession) { return getReadWriteBinding(primary(), readConcern, session, ownsSession); } ReadBinding getReadBinding(final ReadPreference readPreference, final ReadConcern readConcern, @Nullable final ClientSession session, final boolean ownsSession) { return getReadWriteBinding(readPreference, readConcern, session, ownsSession); } ReadWriteBinding getReadWriteBinding(final ReadPreference readPreference, final ReadConcern readConcern, @Nullable final ClientSession session, final boolean ownsSession) { ClusterAwareReadWriteBinding readWriteBinding = new ClusterBinding(cluster, getReadPreferenceForBinding(readPreference, session), readConcern); if (crypt != null) { readWriteBinding = new CryptBinding(readWriteBinding, crypt); } if (session != null) { return new ClientSessionBinding(session, ownsSession, readWriteBinding); } else { return readWriteBinding; } } private void labelException(final @Nullable ClientSession session, final MongoException e) { if (session != null && session.hasActiveTransaction() && (e instanceof MongoSocketException || e instanceof MongoTimeoutException || (e instanceof MongoQueryException && e.getCode() == 91)) && !e.hasErrorLabel(UNKNOWN_TRANSACTION_COMMIT_RESULT_LABEL)) { e.addLabel(TRANSIENT_TRANSACTION_ERROR_LABEL); } } private void unpinServerAddressOnTransientTransactionError(final @Nullable ClientSession session, final MongoException e) { if (session != null && e.hasErrorLabel(TRANSIENT_TRANSACTION_ERROR_LABEL)) { session.setPinnedServerAddress(null); } } private ReadPreference getReadPreferenceForBinding(final ReadPreference readPreference, @Nullable final ClientSession session) { if (session == null) { return readPreference; } if (session.hasActiveTransaction()) { ReadPreference readPreferenceForBinding = session.getTransactionOptions().getReadPreference(); if (readPreferenceForBinding == null) { throw new MongoInternalException("Invariant violated. Transaction options read preference can not be null"); } return readPreferenceForBinding; } return readPreference; } @Nullable ClientSession getClientSession(@Nullable final ClientSession clientSessionFromOperation) { ClientSession session; if (clientSessionFromOperation != null) { isTrue("ClientSession from same MongoClient", clientSessionFromOperation.getOriginator() == originator); session = clientSessionFromOperation; } else { session = createClientSession(ClientSessionOptions.builder().causallyConsistent(false).build(), ReadConcern.DEFAULT, WriteConcern.ACKNOWLEDGED, ReadPreference.primary()); } return session; } } }