AHeise commented on a change in pull request #16783:
URL: https://github.com/apache/flink/pull/16783#discussion_r687670107
##########
File path:
flink-connectors/flink-connector-kafka/src/main/java/org/apache/flink/streaming/connectors/kafka/sink/KafkaRecordSerializationSchema.java
##########
@@ -82,4 +87,97 @@ default void open(SerializationSchema.InitializationContext
context) throws Exce
*/
int[] getPartitionsForTopic(String topic);
}
+
+ /**
+ * Convenience wrapper to write value-only to Kafka with a derived topic.
+ *
+ * @param topicSupplier to derive a topic from the incoming elements
Review comment:
`topicSelector`?
##########
File path:
flink-connectors/flink-connector-kafka/src/main/java/org/apache/flink/streaming/connectors/kafka/sink/KafkaRecordSerializationSchema.java
##########
@@ -82,4 +87,97 @@ default void open(SerializationSchema.InitializationContext
context) throws Exce
*/
int[] getPartitionsForTopic(String topic);
}
+
+ /**
+ * Convenience wrapper to write value-only to Kafka with a derived topic.
+ *
+ * @param topicSupplier to derive a topic from the incoming elements
+ * @param serializationSchema to serialize the incoming elements to bytes
+ * @param <T> type of the values being serialized
+ * @return A {@link KafkaRecordSerializationSchema} which serializes a
{@link ProducerRecord}
+ * with only a value and a derived topic.
+ */
+ static <T> KafkaRecordSerializationSchema<T> valueOnly(
+ Function<T, String> topicSupplier, SerializationSchema<T>
serializationSchema) {
+ return new KafkaValueOnlyRecordSerializationSchema<>(topicSupplier,
serializationSchema);
+ }
+
+ /**
+ * Convenience wrapper to write value-only to Kafka with a fixed topic.
+ *
+ * @param topic which used as destination for all the records
+ * @param serializationSchema to serialize the incoming elements to bytes
+ * @param <T> type of the values being serialized
+ * @return A {@link KafkaRecordSerializationSchema} which serializes a
{@link ProducerRecord}
+ * with only a value and a fixed topic.
+ */
+ static <T> KafkaRecordSerializationSchema<T> valueOnly(
+ String topic, SerializationSchema<T> serializationSchema) {
+ return valueOnly((element) -> topic, serializationSchema);
+ }
+
+ /**
+ * Schema wrapper to write value-only to Kafka with a fixed topic. It
supports Kafka's
+ * serialization stack by serialization with {@link Serializer}.
+ *
+ * @param topicSupplier to derive a topic from the incoming elements
+ * @param serializerClass Kafka's {@link Serializer} to convert the
incoming elements tu bytes
+ * @param <T> type of the values being serialized
+ * @return A {@link KafkaRecordSerializationSchema} which serializes a
{@link ProducerRecord}
+ * with only a value and a fixed topic.
+ */
+ static <T> KafkaRecordSerializationSchema<T> valueOnly(
+ Function<T, String> topicSupplier, Class<? extends Serializer<T>>
serializerClass) {
Review comment:
I think that this is only the start of the story. Folks will ask if we
can also support a Serializer for Key and maybe the partitioner?
At that time we will use a return value that is specialized and will only
additional configuration.
`valueOnly(...).withKeySerializer(...).withPartitioner(...)`. Most of the
things can be done later but it's obvious that `valueOnly` would then be a
misfit.
I'd recommend to rename all valueOnly to some `forX`, like
`forKafkaSerializer`. I'm also thinking that we should only have two root
convenience methods now:
`forKafkaSerializer(Class<?> ).withConfiguration(Map<String, String>)` for
some kind of builder pattern (I'm also fine with replacing `withConfiguration`
with `setConfiguration`). The `build` method would then be
`.withTopicSelector/intoTopic`.
and a similar thing `forSerializationSchema`.
I know this is a bigger change to this PR and might not make it into 1.14
but it's better than having 7 deprecated methods in the near future.
##########
File path:
flink-connectors/flink-connector-kafka/src/main/java/org/apache/flink/streaming/connectors/kafka/sink/KafkaValueOnlySerializer.java
##########
@@ -0,0 +1,76 @@
+/*
+ * 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.connectors.kafka.sink;
+
+import org.apache.flink.api.common.serialization.SerializationSchema;
+import org.apache.flink.util.InstantiationUtil;
+import org.apache.flink.util.TemporaryClassLoaderContext;
+
+import org.apache.kafka.clients.producer.ProducerRecord;
+import org.apache.kafka.common.Configurable;
+import org.apache.kafka.common.serialization.Serializer;
+
+import java.io.IOException;
+import java.util.Map;
+import java.util.function.Function;
+
+/** A simple serialization schema to support Kafka's {@link Serializer}. */
+class KafkaValueOnlySerializer<IN> implements
KafkaRecordSerializationSchema<IN> {
Review comment:
`KafkaValueOnlyKafkaSerializer`? I had a hard time to understand the
difference between this and `KafkaValueOnlyRecordSerializationSchema`.
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