vcrfxia commented on code in PR #13252: URL: https://github.com/apache/kafka/pull/13252#discussion_r1116529217
########## streams/src/main/java/org/apache/kafka/streams/state/internals/MeteredVersionedKeyValueStore.java: ########## @@ -0,0 +1,231 @@ +/* + * 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.kafka.streams.state.internals; + +import static org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl.maybeMeasureLatency; + +import java.util.Objects; +import org.apache.kafka.common.serialization.Serde; +import org.apache.kafka.common.utils.Time; +import org.apache.kafka.streams.errors.ProcessorStateException; +import org.apache.kafka.streams.processor.ProcessorContext; +import org.apache.kafka.streams.processor.StateStore; +import org.apache.kafka.streams.processor.StateStoreContext; +import org.apache.kafka.streams.processor.internals.SerdeGetter; +import org.apache.kafka.streams.query.Position; +import org.apache.kafka.streams.query.PositionBound; +import org.apache.kafka.streams.query.Query; +import org.apache.kafka.streams.query.QueryConfig; +import org.apache.kafka.streams.query.QueryResult; +import org.apache.kafka.streams.state.KeyValueStore; +import org.apache.kafka.streams.state.TimestampedKeyValueStore; +import org.apache.kafka.streams.state.ValueAndTimestamp; +import org.apache.kafka.streams.state.VersionedBytesStore; +import org.apache.kafka.streams.state.VersionedKeyValueStore; +import org.apache.kafka.streams.state.VersionedRecord; + +/** + * A metered {@link VersionedKeyValueStore} wrapper that is used for recording operation + * metrics, and hence its inner {@link VersionedBytesStore} implementation does not need to provide + * its own metrics collecting functionality. The inner {@code VersionedBytesStore} of this class + * is a {@link KeyValueStore} of type <Bytes,byte[]>, so we use {@link Serde}s + * to convert from <K,ValueAndTimestamp<V>> to <Bytes,byte[]>. In particular, + * {@link NullableValueAndTimestampSerde} is used since putting a tombstone to a versioned key-value + * store requires putting a null value associated with a timestamp. + * + * @param <K> The key type + * @param <V> The (raw) value type + */ +public class MeteredVersionedKeyValueStore<K, V> + extends WrappedStateStore<VersionedBytesStore, K, V> + implements VersionedKeyValueStore<K, V> { + + private final MeteredVersionedKeyValueStoreInternal internal; + + MeteredVersionedKeyValueStore(final VersionedBytesStore inner, + final String metricScope, + final Time time, + final Serde<K> keySerde, + final Serde<ValueAndTimestamp<V>> valueSerde) { + super(inner); + internal = new MeteredVersionedKeyValueStoreInternal(inner, metricScope, time, keySerde, valueSerde); + } + + /** + * Conceptually, {@link MeteredVersionedKeyValueStore} should {@code extend} + * {@link MeteredKeyValueStore}, but due to type conflicts, we cannot do this. (Specifically, + * the first needs to be {@link VersionedKeyValueStore} while the second is {@link KeyValueStore} + * and the two interfaces conflict.) Thus, we use an internal <it>instance</it> of + * {@code MeteredKeyValueStore} to mimic inheritance instead. + * <p> + * It's not ideal because it requires an extra step to translate between the APIs of + * {@link VersionedKeyValueStore} in {@link MeteredVersionedKeyValueStore} and + * the APIs of {@link TimestampedKeyValueStore} in {@link MeteredVersionedKeyValueStoreInternal}. + * This extra step is all that the methods of {@code MeteredVersionedKeyValueStoreInternal} do. + * <p> + * Note that the addition of {@link #get(Object, long)} and {@link #delete(Object, long)} in + * this class are to match the interface of {@link VersionedKeyValueStore}. + */ + private class MeteredVersionedKeyValueStoreInternal + extends MeteredKeyValueStore<K, ValueAndTimestamp<V>> { + + private final VersionedBytesStore inner; + + MeteredVersionedKeyValueStoreInternal(final VersionedBytesStore inner, + final String metricScope, + final Time time, + final Serde<K> keySerde, + final Serde<ValueAndTimestamp<V>> valueSerde) { + super(inner, metricScope, time, keySerde, valueSerde); + this.inner = inner; + } + + @Override + public void put(final K key, final ValueAndTimestamp<V> value) { + if (value == null) { + throw new IllegalStateException("Versioned store requires timestamp associated with all puts, including tombstones/deletes"); + } + super.put(key, value); + } + + public ValueAndTimestamp<V> get(final K key, final long asOfTimestamp) { + Objects.requireNonNull(key, "key cannot be null"); + try { + return maybeMeasureLatency(() -> outerValue(inner.get(keyBytes(key), asOfTimestamp)), time, getSensor); + } catch (final ProcessorStateException e) { + final String message = String.format(e.getMessage(), key); + throw new ProcessorStateException(message, e); + } + } + + public ValueAndTimestamp<V> delete(final K key, final long timestamp) { + Objects.requireNonNull(key, "key cannot be null"); + try { + return maybeMeasureLatency(() -> outerValue(inner.delete(keyBytes(key), timestamp)), time, deleteSensor); + } catch (final ProcessorStateException e) { + final String message = String.format(e.getMessage(), key); + throw new ProcessorStateException(message, e); + } + } + + @Override + protected <R> QueryResult<R> runRangeQuery(final Query<R> query, + final PositionBound positionBound, + final QueryConfig config) { + // throw exception for now to reserve the ability to implement this in the future + // without clashing with users' custom implementations in the meantime + throw new UnsupportedOperationException("Versioned stores do not support RangeQuery queries at this time."); + } + + @Override + protected <R> QueryResult<R> runKeyQuery(final Query<R> query, + final PositionBound positionBound, + final QueryConfig config) { + // throw exception for now to reserve the ability to implement this in the future + // without clashing with users' custom implementations in the meantime + throw new UnsupportedOperationException("Versioned stores do not support KeyQuery queries at this time."); + } + + @SuppressWarnings("unchecked") + @Override + protected Serde<ValueAndTimestamp<V>> prepareValueSerdeForStore( + final Serde<ValueAndTimestamp<V>> valueSerde, + final SerdeGetter getter + ) { + if (valueSerde == null) { + return new NullableValueAndTimestampSerde<>((Serde<V>) getter.valueSerde()); + } else { + return super.prepareValueSerdeForStore(valueSerde, getter); + } + } + } + + @Override + public void put(final K key, final V value, final long timestamp) { + internal.put(key, ValueAndTimestamp.makeAllowNullable(value, timestamp)); + } + + @Override + public VersionedRecord<V> delete(final K key, final long timestamp) { + final ValueAndTimestamp<V> valueAndTimestamp = internal.delete(key, timestamp); + return valueAndTimestamp == null + ? null + : new VersionedRecord<>(valueAndTimestamp.value(), valueAndTimestamp.timestamp()); + } + + @Override + public VersionedRecord<V> get(final K key) { + final ValueAndTimestamp<V> valueAndTimestamp = internal.get(key); + return valueAndTimestamp == null + ? null + : new VersionedRecord<>(valueAndTimestamp.value(), valueAndTimestamp.timestamp()); + } + + @Override + public VersionedRecord<V> get(final K key, final long asOfTimestamp) { + final ValueAndTimestamp<V> valueAndTimestamp = internal.get(key, asOfTimestamp); + return valueAndTimestamp == null + ? null + : new VersionedRecord<>(valueAndTimestamp.value(), valueAndTimestamp.timestamp()); + } + + @Override + public String name() { Review Comment: All methods from `MeteredVersionedKeyValueStore` delegate to `internal`; the methods in `MeteredVersionedKeyValueStore` are purely a wrapper for the internal `MeteredVersionedKeyValueStoreInternal` instance. All the actual logic happens in `MeteredVersionedKeyValueStoreInternal`, which delegates its methods to `inner`, which is the actual inner store (either a changelogging layer or the inner versioned store implementation itself). The only reason that `MeteredVersionedKeyValueStore` implements `WrappedStateStore` at all is because there are places in the DSL code which expect the outermost store layer to be a `WrappedStateStore` in order to call methods such as `setFlushListener()` and `flushCache()`. -- 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: jira-unsubscr...@kafka.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
