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https://issues.apache.org/jira/browse/FLINK-3311?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15226369#comment-15226369
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ASF GitHub Bot commented on FLINK-3311:
---------------------------------------
Github user rmetzger commented on a diff in the pull request:
https://github.com/apache/flink/pull/1771#discussion_r58548581
--- Diff:
flink-streaming-connectors/flink-connector-cassandra/src/main/java/org/apache/flink/batch/connectors/cassandra/CassandraOutputFormat.java
---
@@ -0,0 +1,123 @@
+/*
+ * 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.batch.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.base.Strings;
+import com.google.common.util.concurrent.FutureCallback;
+import com.google.common.util.concurrent.Futures;
+import org.apache.flink.api.common.io.RichOutputFormat;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.configuration.Configuration;
+import org.apache.flink.streaming.connectors.cassandra.ClusterBuilder;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+
+/**
+ * OutputFormat to write {@link org.apache.flink.api.java.tuple.Tuple}
into Apache Cassandra.
+ *
+ * @param <OUT> type of Tuple
+ */
+public class CassandraOutputFormat<OUT extends Tuple> extends
RichOutputFormat<OUT> {
+ private static final Logger LOG =
LoggerFactory.getLogger(CassandraOutputFormat.class);
+
+ private final String insertQuery;
+ private final ClusterBuilder builder;
+
+ private transient Cluster cluster;
+ private transient Session session;
+ private transient PreparedStatement prepared;
+ private transient FutureCallback<ResultSet> callback;
+ private transient Throwable exception = null;
+
+ public CassandraOutputFormat(String insertQuery, ClusterBuilder
builder) {
+ if (Strings.isNullOrEmpty(insertQuery)) {
+ throw new IllegalArgumentException("insertQuery cannot
be null or empty");
+ }
+ if (builder == null) {
+ throw new IllegalArgumentException("Builder cannot be
null.");
+ }
+ this.insertQuery = insertQuery;
+ this.builder = builder;
+ }
+
+ @Override
+ public void configure(Configuration parameters) {
+ this.cluster = builder.getCluster();
+ }
+
+ /**
+ * Opens a Session to Cassandra and initializes the prepared statement.
+ *
+ * @param taskNumber The number of the parallel instance.
+ * @throws IOException Thrown, if the output could not be opened due to
an
+ * I/O problem.
+ */
+ @Override
+ public void open(int taskNumber, int numTasks) throws IOException {
+ this.session = cluster.connect();
+ this.prepared = session.prepare(insertQuery);
+ this.callback = new FutureCallback<ResultSet>() {
+ @Override
+ public void onSuccess(ResultSet ignored) {
+ }
+
+ @Override
+ public void onFailure(Throwable t) {
+ exception = t;
+ }
+ };
+ }
+
+ @Override
+ public void writeRecord(OUT record) throws IOException {
+ if (exception != null) {
+ throw new IOException("write record failed", exception);
+ }
+
+ Object[] fields = new Object[record.getArity()];
+ for (int i = 0; i < record.getArity(); i++) {
+ fields[i] = record.getField(i);
+ }
+ ResultSetFuture result =
session.executeAsync(prepared.bind(fields));
+ Futures.addCallback(result, callback);
+ }
+
+ /**
+ * Closes all resources used.
+ */
+ @Override
+ public void close() throws IOException {
+ try {
+ session.close();
+ } catch (Exception e) {
+ LOG.info("Inputformat couldn't be closed - " +
e.getMessage());
--- End diff --
I would make this a WARN and forward the cause to the log entry
> Add a connector for streaming data into Cassandra
> -------------------------------------------------
>
> Key: FLINK-3311
> URL: https://issues.apache.org/jira/browse/FLINK-3311
> Project: Flink
> Issue Type: New Feature
> Components: Streaming Connectors
> Reporter: Robert Metzger
> Assignee: Andrea Sella
>
> We had users in the past asking for a Flink+Cassandra integration.
> It seems that there is a well-developed java client for connecting into
> Cassandra: https://github.com/datastax/java-driver (ASL 2.0)
> There are also tutorials out there on how to start a local cassandra instance
> (for the tests):
> http://prettyprint.me/prettyprint.me/2010/02/14/running-cassandra-as-an-embedded-service/index.html
> For the data types, I think we should support TupleX types, and map standard
> java types to the respective cassandra types.
> In addition, it seems that there is a object mapper from datastax to store
> POJOs in Cassandra (there are annotations for defining the primary key and
> types)
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