org.apache.druid.sql.avatica.DruidConnection.java Source code

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Here is the source code for org.apache.druid.sql.avatica.DruidConnection.java

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/*
 * 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.druid.sql.avatica;

import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSortedMap;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;
import org.apache.druid.java.util.common.ISE;
import org.apache.druid.java.util.common.logger.Logger;

import javax.annotation.Nullable;
import javax.annotation.concurrent.GuardedBy;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;

/**
 * Connection tracking for {@link DruidMeta}. Thread-safe.
 */
public class DruidConnection {
    private static final Logger log = new Logger(DruidConnection.class);
    private static final Set<String> SENSITIVE_CONTEXT_FIELDS = Sets.newHashSet("user", "password");

    private final String connectionId;
    private final int maxStatements;
    private final ImmutableMap<String, Object> context;
    private final AtomicInteger statementCounter = new AtomicInteger();
    private final AtomicReference<Future<?>> timeoutFuture = new AtomicReference<>();

    @GuardedBy("statements")
    private final Map<Integer, DruidStatement> statements;

    @GuardedBy("statements")
    private boolean open = true;

    public DruidConnection(final String connectionId, final int maxStatements, final Map<String, Object> context) {
        this.connectionId = Preconditions.checkNotNull(connectionId);
        this.maxStatements = maxStatements;
        this.context = ImmutableMap.copyOf(context);
        this.statements = new HashMap<>();
    }

    public DruidStatement createStatement() {
        final int statementId = statementCounter.incrementAndGet();

        synchronized (statements) {
            if (statements.containsKey(statementId)) {
                // Will only happen if statementCounter rolls over before old statements are cleaned up. If this
                // ever happens then something fishy is going on, because we shouldn't have billions of statements.
                throw new ISE("Uh oh, too many statements");
            }

            if (statements.size() >= maxStatements) {
                throw new ISE("Too many open statements, limit is[%,d]", maxStatements);
            }

            // remove sensitive fields from the context, only the connection's context needs to have authentication
            // credentials
            Map<String, Object> sanitizedContext = Maps.newHashMap();
            sanitizedContext = Maps.filterEntries(context, new Predicate<Map.Entry<String, Object>>() {
                @Override
                public boolean apply(@Nullable Map.Entry<String, Object> input) {
                    return !SENSITIVE_CONTEXT_FIELDS.contains(input.getKey());
                }
            });

            final DruidStatement statement = new DruidStatement(connectionId, statementId,
                    ImmutableSortedMap.copyOf(sanitizedContext), () -> {
                        // onClose function for the statement
                        synchronized (statements) {
                            log.debug("Connection[%s] closed statement[%s].", connectionId, statementId);
                            statements.remove(statementId);
                        }
                    });

            statements.put(statementId, statement);
            log.debug("Connection[%s] opened statement[%s].", connectionId, statementId);
            return statement;
        }
    }

    public DruidStatement getStatement(final int statementId) {
        synchronized (statements) {
            return statements.get(statementId);
        }
    }

    /**
     * Closes this connection if it has no statements.
     *
     * @return true if closed
     */
    public boolean closeIfEmpty() {
        synchronized (statements) {
            if (statements.isEmpty()) {
                close();
                return true;
            } else {
                return false;
            }
        }
    }

    public void close() {
        synchronized (statements) {
            // Copy statements before iterating because statement.close() modifies it.
            for (DruidStatement statement : ImmutableList.copyOf(statements.values())) {
                try {
                    statement.close();
                } catch (Exception e) {
                    log.warn("Connection[%s] failed to close statement[%s]!", connectionId,
                            statement.getStatementId());
                }
            }

            log.debug("Connection[%s] closed.", connectionId);
            open = false;
        }
    }

    public DruidConnection sync(final Future<?> newTimeoutFuture) {
        final Future<?> oldFuture = timeoutFuture.getAndSet(newTimeoutFuture);
        if (oldFuture != null) {
            oldFuture.cancel(false);
        }
        return this;
    }

    public Map<String, Object> context() {
        return context;
    }
}