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https://issues.apache.org/jira/browse/FLINK-3311?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15195247#comment-15195247
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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_r56156990
--- Diff:
flink-streaming-connectors/flink-connector-cassandra/src/main/java/org/apache/flink/batch/connectors/cassandra/CassandraInputFormat.java
---
@@ -0,0 +1,129 @@
+/*
+ * 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.ResultSet;
+import com.datastax.driver.core.Row;
+import com.datastax.driver.core.Session;
+import com.google.common.base.Strings;
+import org.apache.flink.api.common.io.DefaultInputSplitAssigner;
+import org.apache.flink.api.common.io.NonParallelInput;
+import org.apache.flink.api.common.io.RichInputFormat;
+import org.apache.flink.api.common.io.statistics.BaseStatistics;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.configuration.Configuration;
+import org.apache.flink.core.io.GenericInputSplit;
+import org.apache.flink.core.io.InputSplit;
+import org.apache.flink.core.io.InputSplitAssigner;
+import org.apache.flink.streaming.connectors.cassandra.ClusterBuilder;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+
+/**
+ * InputFormat to read data from Apache Cassandra and generate ${@link
Tuple}.
+ *
+ * @param <OUT> type of Tuple
+ */
+public class CassandraInputFormat<OUT extends Tuple> extends
RichInputFormat<OUT, InputSplit> implements NonParallelInput {
+ private static final Logger LOG =
LoggerFactory.getLogger(CassandraInputFormat.class);
+
+ private final String query;
+ private final ClusterBuilder builder;
+
+ private transient Cluster cluster;
+ private transient Session session;
+ private transient ResultSet resultSet;
+
+ public CassandraInputFormat(String query, ClusterBuilder builder) {
+ if (Strings.isNullOrEmpty(query)) {
+ throw new IllegalArgumentException("Query cannot be
null or empty");
+ }
+ if (builder == null) {
+ throw new IllegalArgumentException("Builder cannot be
null.");
+ }
+ this.query = query;
+ this.builder = builder;
+ }
+
+ @Override
+ public void configure(Configuration parameters) {
+ this.cluster = builder.getCluster();
+ }
+
+ @Override
+ public BaseStatistics getStatistics(BaseStatistics cachedStatistics)
throws IOException {
+ return cachedStatistics;
+ }
+
+ /**
+ * Opens a Session and executes the query.
+ *
+ * @param ignored
+ * @throws IOException
+ */
+ @Override
+ public void open(InputSplit ignored) throws IOException {
+ this.session = cluster.connect();
+ this.resultSet = session.execute(query);
+ }
+
+ @Override
+ public boolean reachedEnd() throws IOException {
+ return resultSet.isExhausted();
+ }
+
+ @Override
+ public OUT nextRecord(OUT reuse) throws IOException {
+ final Row item = resultSet.one();
+ for (int i = 0; i < reuse.getArity(); i++) {
+ reuse.setField(item.getObject(i), i);
+ }
+ return reuse;
+ }
+
+ @Override
+ public InputSplit[] createInputSplits(int minNumSplits) throws
IOException {
+ GenericInputSplit[] split = {new GenericInputSplit(0, 1)};
+ return split;
+ }
+
+ @Override
+ public InputSplitAssigner getInputSplitAssigner(InputSplit[]
inputSplits) {
+ return new DefaultInputSplitAssigner(inputSplits);
+ }
+
+ /**
+ * 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());
+ }
+
+ try {
+ cluster.close();
+ } catch (Exception e) {
+ LOG.info("Inputformat couldn't be closed - " +
e.getMessage());
--- End diff --
I would add the cause in both cases.
> 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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