fapaul commented on a change in pull request #16701:
URL: https://github.com/apache/flink/pull/16701#discussion_r683172137
##########
File path:
flink-core/src/main/java/org/apache/flink/api/connector/sink/Sink.java
##########
@@ -48,41 +54,70 @@
public interface Sink<InputT, CommT, WriterStateT, GlobalCommT> extends
Serializable {
/**
- * Create a {@link SinkWriter}.
+ * Create a {@link SinkWriter}. If the application is resumed from a
checkpoint or savepoint and
+ * the sink is stateful, it will receive the corresponding state obtained
with {@link
+ * SinkWriter#snapshotState()} and serialized with {@link
#getWriterStateSerializer()}. If no
+ * state exists, the first existing, compatible state specified in {@link
+ * #getCompatibleStateNames()} will be loaded and passed.
*
* @param context the runtime context.
- * @param states the writer's state.
+ * @param states the writer's previous state.
* @return A sink writer.
- * @throws IOException if fail to create a writer.
+ * @throws IOException for any failure during creation.
+ * @see SinkWriter#snapshotState()
+ * @see #getWriterStateSerializer()
+ * @see #getCompatibleStateNames()
*/
SinkWriter<InputT, CommT, WriterStateT> createWriter(
InitContext context, List<WriterStateT> states) throws IOException;
/**
- * Creates a {@link Committer}.
+ * Any stateful sink needs to provide this state serializer and implement
{@link
+ * SinkWriter#snapshotState()} properly. The respective state is used in
{@link
+ * #createWriter(InitContext, List)} on recovery.
+ *
+ * @return the serializer of the writer's state type.
+ */
+ Optional<SimpleVersionedSerializer<WriterStateT>>
getWriterStateSerializer();
+
+ /**
+ * Creates a {@link Committer} which is part of a 2-phase-commit protocol.
The {@link
+ * SinkWriter} creates committables through {@link
SinkWriter#prepareCommit(boolean)} in the
+ * first phase. The committables are then passed to this committer and
persisted with {@link
+ * Committer#commit(List)}. If a committer is returned, the sink must also
return a {@link
+ * #getCommittableSerializer()}.
*
- * @return A committer.
- * @throws IOException if fail to create a committer.
+ * @return A committer for the 2-phase-commit protocol.
+ * @throws IOException for any failure during creation.
*/
Optional<Committer<CommT>> createCommitter() throws IOException;
/**
- * Creates a {@link GlobalCommitter}.
+ * Creates a {@link GlobalCommitter} which is part of a 2-phase-commit
protocol. The {@link
+ * SinkWriter} creates committables through {@link
SinkWriter#prepareCommit(boolean)} in the
+ * first phase. The committables are then passed to the Committer and
persisted with {@link
+ * Committer#commit(List)} which also can return an aggregated
committable. This aggregated
Review comment:
Is this correct? AFAIK the return of `Committer#commit()` is only used
to retry these committables later. Unfortunately, this is not implemented yet,
so it will throw once the list is not empty.
##########
File path:
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/sink/CommitterHandler.java
##########
@@ -0,0 +1,71 @@
+/*
+ * 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.flink.streaming.runtime.operators.sink;
+
+import org.apache.flink.runtime.state.StateInitializationContext;
+import org.apache.flink.runtime.state.StateSnapshotContext;
+import org.apache.flink.util.function.SupplierWithException;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * A wrapper around multiple {@link
org.apache.flink.api.connector.sink.Committer} or {@link
+ * org.apache.flink.api.connector.sink.GlobalCommitter} that manages states.
+ *
+ * @param <InputT>
+ * @param <OutputT>
+ */
+interface CommitterHandler<InputT, OutputT> extends AutoCloseable,
Serializable {
+
+ /** Initializes the state of the committer and this handler. */
+ default void initializeState(StateInitializationContext context) throws
Exception {}
+
+ /** Snapshots the state of the committer and this handler. */
+ default void snapshotState(StateSnapshotContext context) throws Exception
{}
Review comment:
We can also move these to methods to `AbstractStreamingCommitterHandler`
because AFAIS they are not necessary for the batch committers.
##########
File path:
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/sink/AbstractCommitterHandler.java
##########
@@ -0,0 +1,53 @@
+/*
+ * 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.flink.streaming.runtime.operators.sink;
+
+import org.apache.flink.util.function.SupplierWithException;
+
+import java.io.IOException;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Deque;
+import java.util.List;
+
+abstract class AbstractCommitterHandler<InputT, OutputT>
+ implements CommitterHandler<InputT, OutputT> {
+
+ /** Record all the committables until commit. */
+ private final Deque<InputT> committables = new ArrayDeque<>();
+
+ @Override
+ public List<OutputT> processCommittables(
+ SupplierWithException<List<InputT>, IOException>
committableSupplier)
+ throws IOException {
+ this.committables.addAll(committableSupplier.get());
+ return Collections.emptyList();
+ }
+
+ public List<InputT> pollCommittables() {
Review comment:
```suggestion
protected List<InputT> pollCommittables() {
```
?
##########
File path:
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/sink/CommitterHandler.java
##########
@@ -0,0 +1,71 @@
+/*
+ * 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.flink.streaming.runtime.operators.sink;
+
+import org.apache.flink.runtime.state.StateInitializationContext;
+import org.apache.flink.runtime.state.StateSnapshotContext;
+import org.apache.flink.util.function.SupplierWithException;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * A wrapper around multiple {@link
org.apache.flink.api.connector.sink.Committer} or {@link
+ * org.apache.flink.api.connector.sink.GlobalCommitter} that manages states.
+ *
+ * @param <InputT>
+ * @param <OutputT>
+ */
+interface CommitterHandler<InputT, OutputT> extends AutoCloseable,
Serializable {
+
+ /** Initializes the state of the committer and this handler. */
+ default void initializeState(StateInitializationContext context) throws
Exception {}
+
+ /** Snapshots the state of the committer and this handler. */
+ default void snapshotState(StateSnapshotContext context) throws Exception
{}
+
+ /**
+ * Processes the committables by either directly transforming them or by
adding them to the
+ * internal state of this handler. The supplier should only be queried
once.
+ *
+ * @return a list of output committables that is send downstream.
+ */
+ List<OutputT> processCommittables(
+ SupplierWithException<List<InputT>, IOException>
committableSupplier)
+ throws IOException;
+
+ /**
+ * Called when no more committables are going to be added through {@link
+ * #processCommittables(SupplierWithException)}.
+ *
+ * @return a list of output committables that is send downstream.
+ */
+ default List<OutputT> endOfInput() throws IOException {
+ return Collections.emptyList();
+ }
+
+ default void close() throws Exception {}
Review comment:
Nit: If the default implementation is only for `NoopCommitterHandler` we
can think of just implementing it there.
##########
File path:
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/sink/CommitterHandler.java
##########
@@ -0,0 +1,71 @@
+/*
+ * 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.flink.streaming.runtime.operators.sink;
+
+import org.apache.flink.runtime.state.StateInitializationContext;
+import org.apache.flink.runtime.state.StateSnapshotContext;
+import org.apache.flink.util.function.SupplierWithException;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * A wrapper around multiple {@link
org.apache.flink.api.connector.sink.Committer} or {@link
+ * org.apache.flink.api.connector.sink.GlobalCommitter} that manages states.
+ *
+ * @param <InputT>
+ * @param <OutputT>
+ */
+interface CommitterHandler<InputT, OutputT> extends AutoCloseable,
Serializable {
+
+ /** Initializes the state of the committer and this handler. */
+ default void initializeState(StateInitializationContext context) throws
Exception {}
+
+ /** Snapshots the state of the committer and this handler. */
+ default void snapshotState(StateSnapshotContext context) throws Exception
{}
+
+ /**
+ * Processes the committables by either directly transforming them or by
adding them to the
+ * internal state of this handler. The supplier should only be queried
once.
+ *
+ * @return a list of output committables that is send downstream.
+ */
+ List<OutputT> processCommittables(
+ SupplierWithException<List<InputT>, IOException>
committableSupplier)
+ throws IOException;
+
+ /**
+ * Called when no more committables are going to be added through {@link
+ * #processCommittables(SupplierWithException)}.
+ *
+ * @return a list of output committables that is send downstream.
+ */
+ default List<OutputT> endOfInput() throws IOException {
Review comment:
Out of curiosity why does the `StreamingCommitterHandler` not implement
`endOfInput`?
##########
File path:
flink-streaming-java/src/test/java/org/apache/flink/streaming/util/TestHarnessUtil.java
##########
@@ -139,6 +139,7 @@ public static void assertNoLateRecords(Iterable<Object>
elements) {
testHarness.processElements(
input.stream().map(StreamRecord::new).collect(Collectors.toList()));
+ testHarness.prepareSnapshotPreBarrier(1);
Review comment:
Nit: Why was this changed needed?
##########
File path:
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/sink/CommitterHandler.java
##########
@@ -0,0 +1,71 @@
+/*
+ * 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.flink.streaming.runtime.operators.sink;
+
+import org.apache.flink.runtime.state.StateInitializationContext;
+import org.apache.flink.runtime.state.StateSnapshotContext;
+import org.apache.flink.util.function.SupplierWithException;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * A wrapper around multiple {@link
org.apache.flink.api.connector.sink.Committer} or {@link
Review comment:
Nit: I find the word `multiple` a bit confusing here because afait it
always exactly wraps one instance of a committer.
##########
File path:
flink-core/src/main/java/org/apache/flink/api/connector/sink/Sink.java
##########
@@ -46,44 +54,81 @@
public interface Sink<InputT, CommT, WriterStateT, GlobalCommT> extends
Serializable {
/**
- * Create a {@link SinkWriter}.
+ * Create a {@link SinkWriter}. If the application is resumed from a
checkpoint or savepoint and
+ * the sink is stateful, it will receive the corresponding state obtained
with {@link
+ * SinkWriter#snapshotState()} and serialized with {@link
#getWriterStateSerializer()}. If no
+ * state exists, the first existing, compatible state specified in {@link
+ * #getCompatibleStateNames()} will be loaded and passed.
*
* @param context the runtime context.
- * @param states the writer's state.
+ * @param states the writer's previous state.
* @return A sink writer.
- * @throws IOException if fail to create a writer.
+ * @throws IOException for any failure during creation.
+ * @see SinkWriter#snapshotState()
+ * @see #getWriterStateSerializer()
+ * @see #getCompatibleStateNames()
*/
SinkWriter<InputT, CommT, WriterStateT> createWriter(
InitContext context, List<WriterStateT> states) throws IOException;
/**
- * Creates a {@link Committer}.
+ * Any stateful sink needs to provide this state serializer and implement
{@link
+ * SinkWriter#snapshotState()} properly. The respective state is used in
{@link
+ * #createWriter(InitContext, List)} on recovery.
+ *
+ * @return the serializer of the writer's state type.
+ */
+ Optional<SimpleVersionedSerializer<WriterStateT>>
getWriterStateSerializer();
+
+ /**
+ * Creates a {@link Committer} which is part of a 2-phase-commit protocol.
The {@link
+ * SinkWriter} creates committables through {@link
SinkWriter#prepareCommit(boolean)} in the
+ * first phase. The committables are then passed to this committer and
persisted with {@link
+ * Committer#commit(List)}. If a committer is returned, the sink must also
return a {@link
+ * #getCommittableSerializer()}.
*
- * @return A committer.
- * @throws IOException if fail to create a committer.
+ * @return A committer for the 2-phase-commit protocol.
+ * @throws IOException for any failure during creation.
*/
Optional<Committer<CommT>> createCommitter() throws IOException;
/**
- * Creates a {@link GlobalCommitter}.
+ * Creates a {@link GlobalCommitter} which is part of a 2-phase-commit
protocol. The {@link
+ * SinkWriter} creates committables through {@link
SinkWriter#prepareCommit(boolean)} in the
+ * first phase. The committables are then passed to the Committer and
persisted with {@link
+ * Committer#commit(List)} which also can return an aggregated
committable. This aggregated
+ * committables are passed to this {@link GlobalCommitter} of which only a
single instance
+ * exists. If a global committer is returned, the sink must also return a
{@link
+ * #getCommittableSerializer()} and {@link
#getGlobalCommittableSerializer()}.
*
- * @return A global committer.
- * @throws IOException if fail to create a global committer.
+ * @return A global committer for the 2-phase-commit protocol.
+ * @throws IOException for any failure during creation.
*/
Optional<GlobalCommitter<CommT, GlobalCommT>> createGlobalCommitter()
throws IOException;
- /** Returns the serializer of the committable type. */
+ /**
+ * Returns the serializer of the committable type. The serializer is
required iff the sink has a
+ * {@link Committer} or {@link GlobalCommitter}.
+ */
Optional<SimpleVersionedSerializer<CommT>> getCommittableSerializer();
- /** Returns the serializer of the aggregated committable type. */
+ /**
+ * Returns the serializer of the aggregated committable type. The
serializer is required iff the
+ * sink has a {@link GlobalCommitter}.
+ */
Optional<SimpleVersionedSerializer<GlobalCommT>>
getGlobalCommittableSerializer();
- /** Return the serializer of the writer's state type. */
- Optional<SimpleVersionedSerializer<WriterStateT>>
getWriterStateSerializer();
+ /**
+ * A list of state names of sinks from which the state can be restored.
For example, the new
+ * file sink can resume from the state of an old streaming file sink as a
drop-in replacement
Review comment:
Nit: Maybe use a docstring to reference the example file sinks. The
terms old and new might be forgotten in the future.
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