azotcsit commented on a change in pull request #1213: URL: https://github.com/apache/cassandra/pull/1213#discussion_r723047225
########## File path: src/java/org/apache/cassandra/schema/PartitionDenylist.java ########## @@ -0,0 +1,462 @@ +/* + * 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.cassandra.schema; + +import java.nio.ByteBuffer; +import java.util.HashMap; +import java.util.HashSet; +import java.util.Map; +import java.util.NavigableSet; +import java.util.Set; +import java.util.TreeSet; +import java.util.concurrent.Callable; +import java.util.concurrent.ExecutionException; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.LinkedBlockingQueue; +import java.util.concurrent.ThreadPoolExecutor; +import java.util.concurrent.TimeUnit; + +import com.google.common.cache.CacheBuilder; +import com.google.common.cache.CacheLoader; +import com.google.common.cache.LoadingCache; +import com.google.common.collect.ImmutableSet; +import com.google.common.collect.ImmutableSortedSet; +import com.google.common.util.concurrent.ListenableFuture; +import com.google.common.util.concurrent.ListenableFutureTask; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import org.apache.cassandra.concurrent.ScheduledExecutors; +import org.apache.cassandra.config.DatabaseDescriptor; +import org.apache.cassandra.cql3.UntypedResultSet; +import org.apache.cassandra.db.PartitionPosition; +import org.apache.cassandra.dht.AbstractBounds; +import org.apache.cassandra.dht.Token; +import org.apache.cassandra.exceptions.RequestExecutionException; +import org.apache.cassandra.service.StorageService; +import org.apache.cassandra.service.reads.range.RangeCommands; +import org.apache.cassandra.utils.Hex; +import org.apache.cassandra.utils.Pair; + +import static org.apache.cassandra.cql3.QueryProcessor.process; + +/** + * PartitionDenylist uses the system_distributed.partition_denylist table to maintain a list of denylisted partition keys + * for each keyspace/table. + * + * Keys can be entered manually into the partition_denylist table or via the JMX operation StorageProxyMBean.denylistKey + * + * The denylist is stored as one CQL partition per table, and the denylisted keys are column names in that partition. The denylisted + * keys for each table are cached in memory, and reloaded from the partition_denylist table every 24 hours (default) or when the + * StorageProxyMBean.loadPartitionDenylist is called via JMX. + * + * Concurrency of the cache is provided by the concurrency semantics of the guava LoadingCache. All values (DenylistEntry) are + * immutable collections of keys/tokens which are replaced in whole when the cache refreshes from disk. + */ +public class PartitionDenylist +{ + private static final Logger logger = LoggerFactory.getLogger(PartitionDenylist.class); + public static final String PARTITION_DENYLIST_TABLE = "partition_denylist"; + + private final ExecutorService executor = new ThreadPoolExecutor(2, 2, Long.MAX_VALUE, TimeUnit.SECONDS, new LinkedBlockingQueue<>()); + + /** We effectively don't use our initial empty cache to denylist until the {@link #load()} call which will replace it */ + private volatile LoadingCache<TableId, DenylistEntry> denylist = buildEmptyCache(); + + /** + * Denylist entry is never mutated once constructed, only replaced with a new entry when the cache is refreshed + */ + private static class DenylistEntry + { + public final ImmutableSet<ByteBuffer> keys; + public final ImmutableSortedSet<Token> tokens; + + public DenylistEntry() + { + keys = ImmutableSet.of(); + tokens = ImmutableSortedSet.of(); + } + + public DenylistEntry(final ImmutableSet<ByteBuffer> keys, final ImmutableSortedSet<Token> tokens) + { + this.keys = keys; + this.tokens = tokens; + } + } + + // synchronized on this + private int loadAttempts = 0; + private int loadSuccesses = 0; + + public synchronized int getLoadAttempts() + { + return loadAttempts; + } + public synchronized int getLoadSuccesses() + { + return loadSuccesses; + } + + /** + * Performs initial load of the partition denylist. Should be called at startup and only loads if the operation + * is expected to succeed. If it is not possible to load at call time, a timer is set to retry. + */ + public void initialLoad() + { + if (!DatabaseDescriptor.enablePartitionDenylist()) + return; + + synchronized (this) + { + loadAttempts++; + } + + // Check if there are sufficient nodes to attempt reading all the denylist partitions before issuing the query. + // The pre-check prevents definite range-slice unavailables being marked and triggering an alert. Nodes may still change + // state between the check and the query, but it should significantly reduce the alert volume. + String retryReason = "Insufficient nodes"; + try + { + if (readAllHasSufficientNodes() && load()) + { + return; + } + } + catch (Throwable tr) + { + logger.error("Failed to load partition denylist", tr); + retryReason = "Exception"; + } + + // This path will also be taken on other failures other than UnavailableException, + // but seems like a good idea to retry anyway. + int retryInSeconds = DatabaseDescriptor.getDenylistInitialLoadRetrySeconds(); + logger.info(retryReason + " while loading partition denylist cache. Scheduled retry in {} seconds.", + retryInSeconds); + ScheduledExecutors.optionalTasks.schedule(this::initialLoad, retryInSeconds, TimeUnit.SECONDS); + } + + private boolean readAllHasSufficientNodes() + { + return RangeCommands.sufficientLiveNodesForSelectStar(SystemDistributedKeyspace.PartitionDenylistTable, + DatabaseDescriptor.getDenylistConsistencyLevel()); + } + + /** Helper method as we need to both build cache on initial init but also on reload of cache contents and params */ + private LoadingCache<TableId, DenylistEntry> buildEmptyCache() + { + return CacheBuilder.newBuilder() + .refreshAfterWrite(DatabaseDescriptor.getDenylistRefreshSeconds(), TimeUnit.SECONDS) + .build(new CacheLoader<TableId, DenylistEntry>() + { + @Override + public DenylistEntry load(final TableId tid) throws Exception + { + return getDenylistForTable(tid); + } + + @Override + public ListenableFuture<DenylistEntry> reload(final TableId tid, final DenylistEntry oldValue) + { + ListenableFutureTask<DenylistEntry> task = ListenableFutureTask.create(new Callable<DenylistEntry>() + { + @Override + public DenylistEntry call() + { + final DenylistEntry newEntry = getDenylistForTable(tid); + if (newEntry != null) + return newEntry; + if (oldValue != null) + return oldValue; + return new DenylistEntry(); + } + }); + executor.execute(task); + return task; + } + }); + } + + /** + * We need to fully rebuild a new cache to accommodate deleting items from the denylist and potentially shrinking + * the max allowable size in the list. We do not serve queries out of this denylist until it is populated + * so as not to introduce a window of having a partially filled cache allow denylisted entries. + */ + public boolean load() + { + final long start = System.currentTimeMillis(); + + final Map<TableId, DenylistEntry> allDenylists = getDenylistForAllTables(); + if (allDenylists == null) + return false; + + // On initial load we have the slight overhead of GC'ing our initial empty cache + LoadingCache<TableId, DenylistEntry> newDenylist = buildEmptyCache(); + newDenylist.putAll(allDenylists); + + synchronized (this) + { + loadSuccesses++; + } + denylist = newDenylist; + logger.info("Loaded partition denylist cache in {}ms", System.currentTimeMillis() - start); + return true; + } + + /** + * We expect the caller to confirm that we are working with a valid keyspace and table. Further, we expect the usage + * pattern of this to be one-off key by key, not in a bulk process, so we relead the entire table's deny list entry + * on an addition or removal. + */ + public boolean addKeyToDenylist(final String keyspace, final String table, final ByteBuffer key) + { + if (!isPermitted(keyspace)) + return false; + + final byte[] keyBytes = new byte[key.remaining()]; + key.slice().get(keyBytes); + + final String insert = String.format("INSERT INTO system_distributed.partition_denylist (ks_name, cf_name, key) VALUES ('%s', '%s', 0x%s)", + keyspace, table, Hex.bytesToHex(keyBytes)); + + try + { + process(insert, DatabaseDescriptor.getDenylistConsistencyLevel()); + + // On insert, we refresh the entire table's deny list data. + TableId denyTableId = getTableId(keyspace, table); + denylist.put(denyTableId, getDenylistForTable(getTableId(keyspace, table))); Review comment: Yeah, my point was more about the second part related to sync of denylist cache and CQL table. Also it can be even more complicated if we think about failover scenarios. Looking forward to hearing your thoughts on the final design. -- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
