Yanikovic commented on a change in pull request #15140:
URL: https://github.com/apache/flink/pull/15140#discussion_r594622998
##########
File path:
flink-connectors/flink-connector-rabbitmq2/src/main/java/org/apache/flink/connector/rabbitmq2/sink/README.md
##########
@@ -0,0 +1,63 @@
+# RabbitMQ Sink
+
+Flink's RabbitMQ connector provides a sink which enables you to publish your
stream directly
+to a RabbitMQ exchange in three different consistency modes: at-most-once,
at-least-once,
+and exactly-once. Furthermore, user defined publish options can be used to
customize each message
+options in regard to exchange and publish settings in the RabbitMQ context.
+
+## Consistency Behaviour
+With __at-most-once__, the sink will simply take each message and publish the
serialization of it
+(with publish options if given) to RabbitMQ. At this point the sink gives up
the ownership of the message.
+
+For __at-least-once__ the same process as for at-most-once is executed except
that the ownership of
+the message does not end immediately with publishing it. The sink will keep
the individual publishing
+id for each message as well as the message itself and buffer it as long as it
takes to receive the
+message received acknowledgment from RabbitMQ. Since we are in the need of
buffering messages and waiting
+for their asynchronous acknowledgment, this requires _checkpointing enabled_.
On each checkpoint,
+all to this point buffered (and thus send) but unacknowledged messages will be
stored. Simultaneously,
+on each checkpoint a resend will be triggered to send all unacknowledged
messages once again since
+we have to assume that something went wrong for it during the publishing
process. Since it can take a
+moment until messages get acknowledged from RabbitMQ this can and probably
will result in a message
+duplication and therefore this logic becomes at-least-once.
+
+By contrast, the __exactly-once-mode__ mode will not send messages on receive.
All incoming messages
+will be buffered until a checkpoint is triggered. On each checkpoint all
messages will be
+published/committed as one transaction to ensure the reception acknowledge by
RabbitMQ.
Review comment:
Done
##########
File path:
flink-connectors/flink-connector-rabbitmq2/src/main/java/org/apache/flink/connector/rabbitmq2/sink/README.md
##########
@@ -0,0 +1,63 @@
+# RabbitMQ Sink
+
+Flink's RabbitMQ connector provides a sink which enables you to publish your
stream directly
+to a RabbitMQ exchange in three different consistency modes: at-most-once,
at-least-once,
+and exactly-once. Furthermore, user defined publish options can be used to
customize each message
+options in regard to exchange and publish settings in the RabbitMQ context.
+
+## Consistency Behaviour
+With __at-most-once__, the sink will simply take each message and publish the
serialization of it
+(with publish options if given) to RabbitMQ. At this point the sink gives up
the ownership of the message.
+
+For __at-least-once__ the same process as for at-most-once is executed except
that the ownership of
+the message does not end immediately with publishing it. The sink will keep
the individual publishing
+id for each message as well as the message itself and buffer it as long as it
takes to receive the
+message received acknowledgment from RabbitMQ. Since we are in the need of
buffering messages and waiting
+for their asynchronous acknowledgment, this requires _checkpointing enabled_.
On each checkpoint,
+all to this point buffered (and thus send) but unacknowledged messages will be
stored. Simultaneously,
+on each checkpoint a resend will be triggered to send all unacknowledged
messages once again since
+we have to assume that something went wrong for it during the publishing
process. Since it can take a
+moment until messages get acknowledged from RabbitMQ this can and probably
will result in a message
+duplication and therefore this logic becomes at-least-once.
+
+By contrast, the __exactly-once-mode__ mode will not send messages on receive.
All incoming messages
+will be buffered until a checkpoint is triggered. On each checkpoint all
messages will be
+published/committed as one transaction to ensure the reception acknowledge by
RabbitMQ.
+If successful, all messages which were committed will be given up, otherwise
they will be stored
+and tried to commit again in the next transaction during the next checkpoint.
+This behaviour ensures that each message will be stored in RabbitMQ exactly
once but also has
+a performance drawback. Committing many messages will take time and will thus
increase the overall
+time it takes to do a checkpoint. This can result in checkpoint delays and in
peaks where
+checkpoint have either many or just a few messages. This also correlates to
the latency of each message.
Review comment:
Done
##########
File path:
flink-connectors/flink-connector-rabbitmq2/src/main/java/org/apache/flink/connector/rabbitmq2/sink/RabbitMQSink.java
##########
@@ -0,0 +1,229 @@
+/*
+ * 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.connector.rabbitmq2.sink;
+
+import org.apache.flink.api.common.serialization.DeserializationSchema;
+import org.apache.flink.api.common.serialization.SerializationSchema;
+import org.apache.flink.api.connector.sink.Committer;
+import org.apache.flink.api.connector.sink.GlobalCommitter;
+import org.apache.flink.api.connector.sink.Sink;
+import org.apache.flink.api.connector.sink.SinkWriter;
+import org.apache.flink.connector.rabbitmq2.ConsistencyMode;
+import org.apache.flink.connector.rabbitmq2.RabbitMQConnectionConfig;
+import org.apache.flink.connector.rabbitmq2.sink.state.RabbitMQSinkWriterState;
+import
org.apache.flink.connector.rabbitmq2.sink.state.RabbitMQSinkWriterStateSerializer;
+import org.apache.flink.connector.rabbitmq2.sink.writer.RabbitMQSinkWriterBase;
+import
org.apache.flink.connector.rabbitmq2.sink.writer.specalized.RabbitMQSinkWriterAtLeastOnce;
+import
org.apache.flink.connector.rabbitmq2.sink.writer.specalized.RabbitMQSinkWriterAtMostOnce;
+import
org.apache.flink.connector.rabbitmq2.sink.writer.specalized.RabbitMQSinkWriterExactlyOnce;
+import org.apache.flink.core.io.SimpleVersionedSerializer;
+import org.apache.flink.util.Preconditions;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.annotation.Nullable;
+
+import java.util.List;
+import java.util.Optional;
+
+/**
+ * RabbitMQ sink (publisher) that publishes messages from upstream flink tasks
to a RabbitMQ queue.
Review comment:
Done
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