[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[spdrnl]

Github user spdrnl commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r54090368
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public abstract class GenericExactlyOnceSink extends 
AbstractStreamOperator implements OneInputStreamOperator {
+   private AbstractStateBackend.CheckpointStateOutputView out;
+   private TypeSerializer serializer;
+   protected TypeInformation typeInfo;
+
+   private ExactlyOnceState state = new ExactlyOnceState();
+
+   /**
+* Saves a handle in the state.
+* @param checkpointId
+* @throws IOException
+*/
+   private void saveHandleInState(final long checkpointId) throws 
IOException {
+   //only add handle if a new OperatorState was created since the 
last snapshot/notify
+   if (out != null) {
+   out.writeByte(0); //EOF-byte
+   StateHandle handle = 
out.closeAndGetHandle();
+   if (state.pendingHandles.containsKey(checkpointId)) {
+   
state.pendingHandles.get(checkpointId).add(handle);
+   } else {
+   ArrayList list = 
new ArrayList<>();
+   list.add(handle);
+   state.pendingHandles.put(checkpointId, list);
+   }
+   out = null;
+   }
+   }
+
+   @Override
+   public StreamTaskState snapshotOperatorState(final long checkpointId, 
final long timestamp) throws Exception {
+   StreamTaskState taskState = 
super.snapshotOperatorState(checkpointId, timestamp);
+   saveHandleInState(checkpointId);
+   taskState.setFunctionState(state);
+   return taskState;
+   }
+
+   @Override
+   public void restoreState(StreamTaskState state, long recoveryTimestamp) 
throws Exception {
+   super.restoreState(state, recoveryTimestamp);
+   this.state = (ExactlyOnceState) state.getFunctionState();
+   out = null;
+   }
+
+   @Override
+   public void notifyOfCompletedCheckpoint(long checkpointId) throws 
Exception {
--- End diff --

Apart from Flink specifics it is possible to get Cassandra to 

[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[zentol]

Github user zentol closed the pull request at:

https://github.com/apache/flink/pull/1620


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[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[zentol]

Github user zentol commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52575628
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public abstract class GenericExactlyOnceSink extends 
AbstractStreamOperator implements OneInputStreamOperator {
+   private AbstractStateBackend.CheckpointStateOutputView out;
+   private TypeSerializer serializer;
+   protected TypeInformation typeInfo;
+
+   private ExactlyOnceState state = new ExactlyOnceState();
+
+   /**
+* Saves a handle in the state.
+* @param checkpointId
+* @throws IOException
+*/
+   private void saveHandleInState(final long checkpointId) throws 
IOException {
+   //only add handle if a new OperatorState was created since the 
last snapshot/notify
+   if (out != null) {
+   out.writeByte(0); //EOF-byte
+   StateHandle handle = 
out.closeAndGetHandle();
+   if (state.pendingHandles.containsKey(checkpointId)) {
+   
state.pendingHandles.get(checkpointId).add(handle);
+   } else {
+   ArrayList list = 
new ArrayList<>();
+   list.add(handle);
+   state.pendingHandles.put(checkpointId, list);
+   }
+   out = null;
+   }
+   }
+
+   @Override
+   public StreamTaskState snapshotOperatorState(final long checkpointId, 
final long timestamp) throws Exception {
+   StreamTaskState taskState = 
super.snapshotOperatorState(checkpointId, timestamp);
+   saveHandleInState(checkpointId);
+   taskState.setFunctionState(state);
+   return taskState;
+   }
+
+   @Override
+   public void restoreState(StreamTaskState state, long recoveryTimestamp) 
throws Exception {
+   super.restoreState(state, recoveryTimestamp);
+   this.state = (ExactlyOnceState) state.getFunctionState();
+   out = null;
+   }
+
+   @Override
+   public void notifyOfCompletedCheckpoint(long checkpointId) throws 
Exception {
+   super.notifyOfCompletedCheckpoint(checkpointId);
+   

[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52623142
  
--- Diff: 
flink-streaming-connectors/flink-connector-cassandra/src/main/java/org/apache/flink/streaming/connectors/cassandra/CassandraExactlyOnceSink.java
 ---
@@ -0,0 +1,100 @@
+/**
+ * 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.cassandra;
+
+import com.datastax.driver.core.Cluster;
+import com.datastax.driver.core.PreparedStatement;
+import com.datastax.driver.core.ResultSet;
+import com.datastax.driver.core.ResultSetFuture;
+import com.datastax.driver.core.Session;
+import com.google.common.util.concurrent.FutureCallback;
+import com.google.common.util.concurrent.Futures;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.streaming.runtime.operators.GenericExactlyOnceSink;
+
+/**
+ * Sink that emits its input elements into a Cassandra database. This sink 
is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public class CassandraExactlyOnceSink extends 
GenericExactlyOnceSink {
--- End diff --

Why does it only works for `Tuple` and not a generic type?


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[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[zentol]

Github user zentol commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52623666
  
--- Diff: 
flink-streaming-connectors/flink-connector-cassandra/src/main/java/org/apache/flink/streaming/connectors/cassandra/CassandraExactlyOnceSink.java
 ---
@@ -0,0 +1,100 @@
+/**
+ * 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.cassandra;
+
+import com.datastax.driver.core.Cluster;
+import com.datastax.driver.core.PreparedStatement;
+import com.datastax.driver.core.ResultSet;
+import com.datastax.driver.core.ResultSetFuture;
+import com.datastax.driver.core.Session;
+import com.google.common.util.concurrent.FutureCallback;
+import com.google.common.util.concurrent.Futures;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.streaming.runtime.operators.GenericExactlyOnceSink;
+
+/**
+ * Sink that emits its input elements into a Cassandra database. This sink 
is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public class CassandraExactlyOnceSink extends 
GenericExactlyOnceSink {
--- End diff --

you're right, i forgot about POJO's.


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[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52623648
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public abstract class GenericExactlyOnceSink extends 
AbstractStreamOperator implements OneInputStreamOperator {
+   private AbstractStateBackend.CheckpointStateOutputView out;
+   private TypeSerializer serializer;
+   protected TypeInformation typeInfo;
--- End diff --

The `TypeInformation` shouldn't actually be sent to the cluster. Why do you 
need it here?


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[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52625876
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public abstract class GenericExactlyOnceSink extends 
AbstractStreamOperator implements OneInputStreamOperator {
+   private AbstractStateBackend.CheckpointStateOutputView out;
+   private TypeSerializer serializer;
+   protected TypeInformation typeInfo;
+
+   private ExactlyOnceState state = new ExactlyOnceState();
+
+   /**
+* Saves a handle in the state.
+* @param checkpointId
+* @throws IOException
+*/
+   private void saveHandleInState(final long checkpointId) throws 
IOException {
+   //only add handle if a new OperatorState was created since the 
last snapshot/notify
+   if (out != null) {
+   out.writeByte(0); //EOF-byte
+   StateHandle handle = 
out.closeAndGetHandle();
+   if (state.pendingHandles.containsKey(checkpointId)) {
+   
state.pendingHandles.get(checkpointId).add(handle);
+   } else {
+   ArrayList list = 
new ArrayList<>();
+   list.add(handle);
+   state.pendingHandles.put(checkpointId, list);
+   }
+   out = null;
+   }
+   }
+
+   @Override
+   public StreamTaskState snapshotOperatorState(final long checkpointId, 
final long timestamp) throws Exception {
+   StreamTaskState taskState = 
super.snapshotOperatorState(checkpointId, timestamp);
+   saveHandleInState(checkpointId);
+   taskState.setFunctionState(state);
+   return taskState;
+   }
+
+   @Override
+   public void restoreState(StreamTaskState state, long recoveryTimestamp) 
throws Exception {
+   super.restoreState(state, recoveryTimestamp);
+   this.state = (ExactlyOnceState) state.getFunctionState();
+   out = null;
+   }
+
+   @Override
+   public void notifyOfCompletedCheckpoint(long checkpointId) throws 
Exception {
+   super.notifyOfCompletedCheckpoint(checkpointId);
+   

[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[zentol]

Github user zentol commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52625891
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public abstract class GenericExactlyOnceSink extends 
AbstractStreamOperator implements OneInputStreamOperator {
+   private AbstractStateBackend.CheckpointStateOutputView out;
+   private TypeSerializer serializer;
+   protected TypeInformation typeInfo;
--- End diff --

I'm not sure if it's really needed at all actually, will give it some 
thought.


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[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52621606
  
--- Diff: 
flink-streaming-connectors/flink-connector-cassandra/src/main/java/org/apache/flink/streaming/connectors/cassandra/CassandraExactlyOnceSink.java
 ---
@@ -0,0 +1,100 @@
+/**
+ * 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.cassandra;
+
+import com.datastax.driver.core.Cluster;
+import com.datastax.driver.core.PreparedStatement;
+import com.datastax.driver.core.ResultSet;
+import com.datastax.driver.core.ResultSetFuture;
+import com.datastax.driver.core.Session;
+import com.google.common.util.concurrent.FutureCallback;
+import com.google.common.util.concurrent.Futures;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.streaming.runtime.operators.GenericExactlyOnceSink;
+
+/**
+ * Sink that emits its input elements into a Cassandra database. This sink 
is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public class CassandraExactlyOnceSink extends 
GenericExactlyOnceSink {
+   private String host;
+   private String createQuery;
+   private String insertQuery;
--- End diff --

These fields could be made final, right?


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[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52622167
  
--- Diff: 
flink-streaming-connectors/flink-connector-cassandra/src/main/java/org/apache/flink/streaming/connectors/cassandra/CassandraExactlyOnceSink.java
 ---
@@ -0,0 +1,100 @@
+/**
+ * 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.cassandra;
+
+import com.datastax.driver.core.Cluster;
+import com.datastax.driver.core.PreparedStatement;
+import com.datastax.driver.core.ResultSet;
+import com.datastax.driver.core.ResultSetFuture;
+import com.datastax.driver.core.Session;
+import com.google.common.util.concurrent.FutureCallback;
+import com.google.common.util.concurrent.Futures;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.streaming.runtime.operators.GenericExactlyOnceSink;
+
+/**
+ * Sink that emits its input elements into a Cassandra database. This sink 
is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public class CassandraExactlyOnceSink extends 
GenericExactlyOnceSink {
+   private String host;
+   private String createQuery;
+   private String insertQuery;
+
+   private transient Cluster cluster;
+   private transient Session session;
+   private transient PreparedStatement preparedStatement;
+
+   private transient Throwable exception = null;
+
+   public CassandraExactlyOnceSink(String host, String insertQuery) {
+   this(host, null, insertQuery);
+   }
+
+   public CassandraExactlyOnceSink(String host, String createQuery, String 
insertQuery) {
+   this.host = host;
+   this.createQuery = createQuery;
+   this.insertQuery = insertQuery;
--- End diff --

Adding null checks and non empty checks for the `host` and the 
`insertQuery` could be helpful.


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[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52623063
  
--- Diff: 
flink-streaming-connectors/flink-connector-cassandra/src/main/java/org/apache/flink/streaming/connectors/cassandra/CassandraExactlyOnceSink.java
 ---
@@ -0,0 +1,100 @@
+/**
+ * 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.cassandra;
+
+import com.datastax.driver.core.Cluster;
+import com.datastax.driver.core.PreparedStatement;
+import com.datastax.driver.core.ResultSet;
+import com.datastax.driver.core.ResultSetFuture;
+import com.datastax.driver.core.Session;
+import com.google.common.util.concurrent.FutureCallback;
+import com.google.common.util.concurrent.Futures;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.streaming.runtime.operators.GenericExactlyOnceSink;
+
+/**
+ * Sink that emits its input elements into a Cassandra database. This sink 
is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
--- End diff --

param description missing


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[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52624579
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public abstract class GenericExactlyOnceSink extends 
AbstractStreamOperator implements OneInputStreamOperator {
+   private AbstractStateBackend.CheckpointStateOutputView out;
+   private TypeSerializer serializer;
+   protected TypeInformation typeInfo;
+
+   private ExactlyOnceState state = new ExactlyOnceState();
+
+   /**
+* Saves a handle in the state.
+* @param checkpointId
+* @throws IOException
+*/
+   private void saveHandleInState(final long checkpointId) throws 
IOException {
+   //only add handle if a new OperatorState was created since the 
last snapshot/notify
+   if (out != null) {
+   out.writeByte(0); //EOF-byte
+   StateHandle handle = 
out.closeAndGetHandle();
+   if (state.pendingHandles.containsKey(checkpointId)) {
+   
state.pendingHandles.get(checkpointId).add(handle);
+   } else {
+   ArrayList list = 
new ArrayList<>();
+   list.add(handle);
+   state.pendingHandles.put(checkpointId, list);
+   }
+   out = null;
+   }
+   }
+
+   @Override
+   public StreamTaskState snapshotOperatorState(final long checkpointId, 
final long timestamp) throws Exception {
+   StreamTaskState taskState = 
super.snapshotOperatorState(checkpointId, timestamp);
+   saveHandleInState(checkpointId);
+   taskState.setFunctionState(state);
+   return taskState;
+   }
+
+   @Override
+   public void restoreState(StreamTaskState state, long recoveryTimestamp) 
throws Exception {
+   super.restoreState(state, recoveryTimestamp);
+   this.state = (ExactlyOnceState) state.getFunctionState();
+   out = null;
+   }
+
+   @Override
+   public void notifyOfCompletedCheckpoint(long checkpointId) throws 
Exception {
+   super.notifyOfCompletedCheckpoint(checkpointId);
+   

[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52625364
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public abstract class GenericExactlyOnceSink extends 
AbstractStreamOperator implements OneInputStreamOperator {
+   private AbstractStateBackend.CheckpointStateOutputView out;
+   private TypeSerializer serializer;
+   protected TypeInformation typeInfo;
+
+   private ExactlyOnceState state = new ExactlyOnceState();
+
+   /**
+* Saves a handle in the state.
+* @param checkpointId
+* @throws IOException
+*/
+   private void saveHandleInState(final long checkpointId) throws 
IOException {
+   //only add handle if a new OperatorState was created since the 
last snapshot/notify
+   if (out != null) {
+   out.writeByte(0); //EOF-byte
+   StateHandle handle = 
out.closeAndGetHandle();
+   if (state.pendingHandles.containsKey(checkpointId)) {
+   
state.pendingHandles.get(checkpointId).add(handle);
+   } else {
+   ArrayList list = 
new ArrayList<>();
+   list.add(handle);
+   state.pendingHandles.put(checkpointId, list);
+   }
+   out = null;
+   }
+   }
+
+   @Override
+   public StreamTaskState snapshotOperatorState(final long checkpointId, 
final long timestamp) throws Exception {
+   StreamTaskState taskState = 
super.snapshotOperatorState(checkpointId, timestamp);
+   saveHandleInState(checkpointId);
+   taskState.setFunctionState(state);
+   return taskState;
+   }
+
+   @Override
+   public void restoreState(StreamTaskState state, long recoveryTimestamp) 
throws Exception {
+   super.restoreState(state, recoveryTimestamp);
+   this.state = (ExactlyOnceState) state.getFunctionState();
+   out = null;
+   }
+
+   @Override
+   public void notifyOfCompletedCheckpoint(long checkpointId) throws 
Exception {
+   super.notifyOfCompletedCheckpoint(checkpointId);
+   

[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52622956
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
--- End diff --

param description missing


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[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52623292
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public abstract class GenericExactlyOnceSink extends 
AbstractStreamOperator implements OneInputStreamOperator {
--- End diff --

Can't the input type be a generic type?


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[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52625293
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public abstract class GenericExactlyOnceSink extends 
AbstractStreamOperator implements OneInputStreamOperator {
+   private AbstractStateBackend.CheckpointStateOutputView out;
+   private TypeSerializer serializer;
+   protected TypeInformation typeInfo;
+
+   private ExactlyOnceState state = new ExactlyOnceState();
+
+   /**
+* Saves a handle in the state.
+* @param checkpointId
+* @throws IOException
+*/
+   private void saveHandleInState(final long checkpointId) throws 
IOException {
+   //only add handle if a new OperatorState was created since the 
last snapshot/notify
+   if (out != null) {
+   out.writeByte(0); //EOF-byte
+   StateHandle handle = 
out.closeAndGetHandle();
+   if (state.pendingHandles.containsKey(checkpointId)) {
+   
state.pendingHandles.get(checkpointId).add(handle);
+   } else {
+   ArrayList list = 
new ArrayList<>();
+   list.add(handle);
+   state.pendingHandles.put(checkpointId, list);
+   }
+   out = null;
+   }
+   }
+
+   @Override
+   public StreamTaskState snapshotOperatorState(final long checkpointId, 
final long timestamp) throws Exception {
+   StreamTaskState taskState = 
super.snapshotOperatorState(checkpointId, timestamp);
+   saveHandleInState(checkpointId);
+   taskState.setFunctionState(state);
+   return taskState;
+   }
+
+   @Override
+   public void restoreState(StreamTaskState state, long recoveryTimestamp) 
throws Exception {
+   super.restoreState(state, recoveryTimestamp);
+   this.state = (ExactlyOnceState) state.getFunctionState();
+   out = null;
+   }
+
+   @Override
+   public void notifyOfCompletedCheckpoint(long checkpointId) throws 
Exception {
+   super.notifyOfCompletedCheckpoint(checkpointId);
+   

[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[zentol]

Github user zentol commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52630950
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public abstract class GenericExactlyOnceSink extends 
AbstractStreamOperator implements OneInputStreamOperator {
+   private AbstractStateBackend.CheckpointStateOutputView out;
+   private TypeSerializer serializer;
+   protected TypeInformation typeInfo;
+
+   private ExactlyOnceState state = new ExactlyOnceState();
+
+   /**
+* Saves a handle in the state.
+* @param checkpointId
+* @throws IOException
+*/
+   private void saveHandleInState(final long checkpointId) throws 
IOException {
+   //only add handle if a new OperatorState was created since the 
last snapshot/notify
+   if (out != null) {
+   out.writeByte(0); //EOF-byte
+   StateHandle handle = 
out.closeAndGetHandle();
+   if (state.pendingHandles.containsKey(checkpointId)) {
+   
state.pendingHandles.get(checkpointId).add(handle);
+   } else {
+   ArrayList list = 
new ArrayList<>();
+   list.add(handle);
+   state.pendingHandles.put(checkpointId, list);
+   }
+   out = null;
+   }
+   }
+
+   @Override
+   public StreamTaskState snapshotOperatorState(final long checkpointId, 
final long timestamp) throws Exception {
+   StreamTaskState taskState = 
super.snapshotOperatorState(checkpointId, timestamp);
+   saveHandleInState(checkpointId);
+   taskState.setFunctionState(state);
+   return taskState;
+   }
+
+   @Override
+   public void restoreState(StreamTaskState state, long recoveryTimestamp) 
throws Exception {
+   super.restoreState(state, recoveryTimestamp);
+   this.state = (ExactlyOnceState) state.getFunctionState();
+   out = null;
+   }
+
+   @Override
+   public void notifyOfCompletedCheckpoint(long checkpointId) throws 
Exception {
+   super.notifyOfCompletedCheckpoint(checkpointId);
+   

[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52626959
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public abstract class GenericExactlyOnceSink extends 
AbstractStreamOperator implements OneInputStreamOperator {
+   private AbstractStateBackend.CheckpointStateOutputView out;
+   private TypeSerializer serializer;
+   protected TypeInformation typeInfo;
+
+   private ExactlyOnceState state = new ExactlyOnceState();
+
+   /**
+* Saves a handle in the state.
+* @param checkpointId
+* @throws IOException
+*/
+   private void saveHandleInState(final long checkpointId) throws 
IOException {
+   //only add handle if a new OperatorState was created since the 
last snapshot/notify
+   if (out != null) {
+   out.writeByte(0); //EOF-byte
+   StateHandle handle = 
out.closeAndGetHandle();
+   if (state.pendingHandles.containsKey(checkpointId)) {
+   
state.pendingHandles.get(checkpointId).add(handle);
+   } else {
+   ArrayList list = 
new ArrayList<>();
+   list.add(handle);
+   state.pendingHandles.put(checkpointId, list);
+   }
+   out = null;
+   }
+   }
+
+   @Override
+   public StreamTaskState snapshotOperatorState(final long checkpointId, 
final long timestamp) throws Exception {
+   StreamTaskState taskState = 
super.snapshotOperatorState(checkpointId, timestamp);
+   saveHandleInState(checkpointId);
+   taskState.setFunctionState(state);
+   return taskState;
+   }
+
+   @Override
+   public void restoreState(StreamTaskState state, long recoveryTimestamp) 
throws Exception {
+   super.restoreState(state, recoveryTimestamp);
+   this.state = (ExactlyOnceState) state.getFunctionState();
+   out = null;
+   }
+
+   @Override
+   public void notifyOfCompletedCheckpoint(long checkpointId) throws 
Exception {
+   super.notifyOfCompletedCheckpoint(checkpointId);
+   

[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52631298
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public abstract class GenericExactlyOnceSink extends 
AbstractStreamOperator implements OneInputStreamOperator {
+   private AbstractStateBackend.CheckpointStateOutputView out;
+   private TypeSerializer serializer;
+   protected TypeInformation typeInfo;
+
+   private ExactlyOnceState state = new ExactlyOnceState();
+
+   /**
+* Saves a handle in the state.
+* @param checkpointId
+* @throws IOException
+*/
+   private void saveHandleInState(final long checkpointId) throws 
IOException {
+   //only add handle if a new OperatorState was created since the 
last snapshot/notify
+   if (out != null) {
+   out.writeByte(0); //EOF-byte
+   StateHandle handle = 
out.closeAndGetHandle();
+   if (state.pendingHandles.containsKey(checkpointId)) {
+   
state.pendingHandles.get(checkpointId).add(handle);
+   } else {
+   ArrayList list = 
new ArrayList<>();
+   list.add(handle);
+   state.pendingHandles.put(checkpointId, list);
+   }
+   out = null;
+   }
+   }
+
+   @Override
+   public StreamTaskState snapshotOperatorState(final long checkpointId, 
final long timestamp) throws Exception {
+   StreamTaskState taskState = 
super.snapshotOperatorState(checkpointId, timestamp);
+   saveHandleInState(checkpointId);
+   taskState.setFunctionState(state);
+   return taskState;
+   }
+
+   @Override
+   public void restoreState(StreamTaskState state, long recoveryTimestamp) 
throws Exception {
+   super.restoreState(state, recoveryTimestamp);
+   this.state = (ExactlyOnceState) state.getFunctionState();
+   out = null;
+   }
+
+   @Override
+   public void notifyOfCompletedCheckpoint(long checkpointId) throws 
Exception {
+   super.notifyOfCompletedCheckpoint(checkpointId);
+   

[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52626379
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public abstract class GenericExactlyOnceSink extends 
AbstractStreamOperator implements OneInputStreamOperator {
+   private AbstractStateBackend.CheckpointStateOutputView out;
+   private TypeSerializer serializer;
+   protected TypeInformation typeInfo;
+
+   private ExactlyOnceState state = new ExactlyOnceState();
+
+   /**
+* Saves a handle in the state.
+* @param checkpointId
+* @throws IOException
+*/
+   private void saveHandleInState(final long checkpointId) throws 
IOException {
+   //only add handle if a new OperatorState was created since the 
last snapshot/notify
+   if (out != null) {
+   out.writeByte(0); //EOF-byte
+   StateHandle handle = 
out.closeAndGetHandle();
+   if (state.pendingHandles.containsKey(checkpointId)) {
+   
state.pendingHandles.get(checkpointId).add(handle);
+   } else {
+   ArrayList list = 
new ArrayList<>();
+   list.add(handle);
+   state.pendingHandles.put(checkpointId, list);
+   }
+   out = null;
+   }
+   }
+
+   @Override
+   public StreamTaskState snapshotOperatorState(final long checkpointId, 
final long timestamp) throws Exception {
+   StreamTaskState taskState = 
super.snapshotOperatorState(checkpointId, timestamp);
+   saveHandleInState(checkpointId);
+   taskState.setFunctionState(state);
+   return taskState;
+   }
+
+   @Override
+   public void restoreState(StreamTaskState state, long recoveryTimestamp) 
throws Exception {
+   super.restoreState(state, recoveryTimestamp);
+   this.state = (ExactlyOnceState) state.getFunctionState();
+   out = null;
+   }
+
+   @Override
+   public void notifyOfCompletedCheckpoint(long checkpointId) throws 
Exception {
+   super.notifyOfCompletedCheckpoint(checkpointId);
+   

[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52627131
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public abstract class GenericExactlyOnceSink extends 
AbstractStreamOperator implements OneInputStreamOperator {
+   private AbstractStateBackend.CheckpointStateOutputView out;
+   private TypeSerializer serializer;
+   protected TypeInformation typeInfo;
+
+   private ExactlyOnceState state = new ExactlyOnceState();
+
+   /**
+* Saves a handle in the state.
+* @param checkpointId
+* @throws IOException
+*/
+   private void saveHandleInState(final long checkpointId) throws 
IOException {
+   //only add handle if a new OperatorState was created since the 
last snapshot/notify
+   if (out != null) {
+   out.writeByte(0); //EOF-byte
+   StateHandle handle = 
out.closeAndGetHandle();
+   if (state.pendingHandles.containsKey(checkpointId)) {
+   
state.pendingHandles.get(checkpointId).add(handle);
+   } else {
+   ArrayList list = 
new ArrayList<>();
+   list.add(handle);
+   state.pendingHandles.put(checkpointId, list);
+   }
+   out = null;
+   }
+   }
+
+   @Override
+   public StreamTaskState snapshotOperatorState(final long checkpointId, 
final long timestamp) throws Exception {
+   StreamTaskState taskState = 
super.snapshotOperatorState(checkpointId, timestamp);
+   saveHandleInState(checkpointId);
+   taskState.setFunctionState(state);
+   return taskState;
+   }
+
+   @Override
+   public void restoreState(StreamTaskState state, long recoveryTimestamp) 
throws Exception {
+   super.restoreState(state, recoveryTimestamp);
+   this.state = (ExactlyOnceState) state.getFunctionState();
+   out = null;
+   }
+
+   @Override
+   public void notifyOfCompletedCheckpoint(long checkpointId) throws 
Exception {
+   super.notifyOfCompletedCheckpoint(checkpointId);
+   

[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52630685
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public abstract class GenericExactlyOnceSink extends 
AbstractStreamOperator implements OneInputStreamOperator {
+   private AbstractStateBackend.CheckpointStateOutputView out;
+   private TypeSerializer serializer;
+   protected TypeInformation typeInfo;
+
+   private ExactlyOnceState state = new ExactlyOnceState();
+
+   /**
+* Saves a handle in the state.
+* @param checkpointId
+* @throws IOException
+*/
+   private void saveHandleInState(final long checkpointId) throws 
IOException {
+   //only add handle if a new OperatorState was created since the 
last snapshot/notify
+   if (out != null) {
+   out.writeByte(0); //EOF-byte
+   StateHandle handle = 
out.closeAndGetHandle();
+   if (state.pendingHandles.containsKey(checkpointId)) {
+   
state.pendingHandles.get(checkpointId).add(handle);
+   } else {
+   ArrayList list = 
new ArrayList<>();
+   list.add(handle);
+   state.pendingHandles.put(checkpointId, list);
+   }
+   out = null;
+   }
+   }
+
+   @Override
+   public StreamTaskState snapshotOperatorState(final long checkpointId, 
final long timestamp) throws Exception {
+   StreamTaskState taskState = 
super.snapshotOperatorState(checkpointId, timestamp);
+   saveHandleInState(checkpointId);
+   taskState.setFunctionState(state);
+   return taskState;
+   }
+
+   @Override
+   public void restoreState(StreamTaskState state, long recoveryTimestamp) 
throws Exception {
+   super.restoreState(state, recoveryTimestamp);
+   this.state = (ExactlyOnceState) state.getFunctionState();
+   out = null;
+   }
+
+   @Override
+   public void notifyOfCompletedCheckpoint(long checkpointId) throws 
Exception {
--- End diff --

I guess I have missed something, but how do prevent the 

[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[tillrohrmann]

Github user tillrohrmann commented on the pull request:

https://github.com/apache/flink/pull/1620#issuecomment-182959361
  
Good work @zentol. I had some inline comments.

My main concern is that upon recovery you'll write all elements of the 
previously written checkpoint again to the external store. 


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[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[zentol]

Github user zentol commented on a diff in the pull request:

https://github.com/apache/flink/pull/1620#discussion_r52634496
  
--- Diff: 
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/GenericExactlyOnceSink.java
 ---
@@ -0,0 +1,173 @@
+/**
+ * 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;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.TypeExtractor;
+import org.apache.flink.core.memory.DataInputView;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.StateHandle;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
+import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
+import org.apache.flink.streaming.api.watermark.Watermark;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.StreamTaskState;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Generic Sink that emits its input elements into an arbitrary backend. 
This sink is integrated with the checkpointing
+ * mechanism to provide exactly once semantics.
+ *
+ * Incoming records are stored within a {@link 
org.apache.flink.runtime.state.AbstractStateBackend}, and only committed if a
+ * checkpoint is completed. Should a job fail while the data is being 
committed, no exactly once guarantee can be made.
+ * @param 
+ */
+public abstract class GenericExactlyOnceSink extends 
AbstractStreamOperator implements OneInputStreamOperator {
+   private AbstractStateBackend.CheckpointStateOutputView out;
+   private TypeSerializer serializer;
+   protected TypeInformation typeInfo;
+
+   private ExactlyOnceState state = new ExactlyOnceState();
+
+   /**
+* Saves a handle in the state.
+* @param checkpointId
+* @throws IOException
+*/
+   private void saveHandleInState(final long checkpointId) throws 
IOException {
+   //only add handle if a new OperatorState was created since the 
last snapshot/notify
+   if (out != null) {
+   out.writeByte(0); //EOF-byte
+   StateHandle handle = 
out.closeAndGetHandle();
+   if (state.pendingHandles.containsKey(checkpointId)) {
+   
state.pendingHandles.get(checkpointId).add(handle);
+   } else {
+   ArrayList list = 
new ArrayList<>();
+   list.add(handle);
+   state.pendingHandles.put(checkpointId, list);
+   }
+   out = null;
+   }
+   }
+
+   @Override
+   public StreamTaskState snapshotOperatorState(final long checkpointId, 
final long timestamp) throws Exception {
+   StreamTaskState taskState = 
super.snapshotOperatorState(checkpointId, timestamp);
+   saveHandleInState(checkpointId);
+   taskState.setFunctionState(state);
+   return taskState;
+   }
+
+   @Override
+   public void restoreState(StreamTaskState state, long recoveryTimestamp) 
throws Exception {
+   super.restoreState(state, recoveryTimestamp);
+   this.state = (ExactlyOnceState) state.getFunctionState();
+   out = null;
+   }
+
+   @Override
+   public void notifyOfCompletedCheckpoint(long checkpointId) throws 
Exception {
--- End diff --

I have to look into this.


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[GitHub] flink pull request: [FLINK-3332] Cassandra connector

[zentol]

GitHub user zentol opened a pull request:

https://github.com/apache/flink/pull/1620

[FLINK-3332] Cassandra connector

This PR adds an Exactly-Once Cassandra Sink.

The Exactly-once guarantee is made by saving incoming records in the 
OperatorState, and only committing them into Cassandra when a checkpoint 
completes. Note that a job failure while the data is being committed will cause 
duplicate data to be committed, but the chance of this happening is much 
smaller than for a naive At-Least-once implementation.

The CassandraExactlyOnceSink is implemented as a custom operator to get 
access to the Statebackend. Values are committed with single inserts using a 
PreparedStatement that is supplied by the user, similiar to the Batch 
JDBC-Outputformat.

The Exactly-Once logic is completely contained in a GenericExactlyOnceSink 
class that can be used by virtually every sink, requiring no knowledge about 
the checkpointing mechamism.

The CassandraExactlyOnceSink and GenericExactlyOnceSink are covered by 
tests that use the OneInputStreamTaskHarness to generate a task environment, 
verifying that stored data is discarded when a state is restored; all data is 
being committed when a notify is missed; and of course that everything works 
when nothing goes wrong.

Note: This PR currently subsumes #1609 (the change to 
ResultPartitionWriter), so that the tests run properly.

You can merge this pull request into a Git repository by running:

$ git pull https://github.com/zentol/flink 3332_cassandra

Alternatively you can review and apply these changes as the patch at:

https://github.com/apache/flink/pull/1620.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

This closes #1620


commit 64f0b32c9292f1c5957badbcee30476b663eb5a1
Author: zentol 
Date:   2016-02-10T13:14:18Z

[FLINK-3332] Cassandra connector




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