org.apache.flink.streaming.experimental.CollectSink Maven / Gradle / Ivy
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* 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.experimental;
import org.apache.flink.annotation.Experimental;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.core.memory.DataOutputViewStreamWrapper;
import org.apache.flink.streaming.api.functions.sink.RichSinkFunction;
import java.io.IOException;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;
/**
* A specialized data sink to be used by DataStreamUtils.collect().
*
* This experimental class is relocated from flink-streaming-contrib. Please see
* package-info.java for more information.
*/
@Experimental
public class CollectSink extends RichSinkFunction {
private static final long serialVersionUID = 1L;
private final InetAddress hostIp;
private final int port;
private final TypeSerializer serializer;
private transient Socket client;
private transient OutputStream outputStream;
private transient DataOutputViewStreamWrapper streamWriter;
/**
* Creates a CollectSink that will send the data to the specified host.
*
* @param hostIp IP address of the Socket server.
* @param port Port of the Socket server.
* @param serializer A serializer for the data.
*/
public CollectSink(InetAddress hostIp, int port, TypeSerializer serializer) {
this.hostIp = hostIp;
this.port = port;
this.serializer = serializer;
}
@Override
public void invoke(IN value, Context context) throws Exception {
try {
serializer.serialize(value, streamWriter);
} catch (Exception e) {
throw new IOException(
"Error sending data back to client (" + hostIp.toString() + ":" + port + ')',
e);
}
}
/**
* Initialize the connection with the Socket in the server.
*
* @param parameters Configuration.
*/
@Override
public void open(Configuration parameters) throws Exception {
try {
client = new Socket(hostIp, port);
outputStream = client.getOutputStream();
streamWriter = new DataOutputViewStreamWrapper(outputStream);
} catch (IOException e) {
throw new IOException(
"Cannot get back the stream while opening connection to client at "
+ hostIp.toString()
+ ":"
+ port,
e);
}
}
/** Closes the connection with the Socket server. */
@Override
public void close() throws Exception {
try {
if (outputStream != null) {
outputStream.flush();
outputStream.close();
}
// first regular attempt to cleanly close. Failing that will escalate
if (client != null) {
client.close();
}
} catch (Exception e) {
throw new IOException(
"Error while closing connection that streams data back to client at "
+ hostIp.toString()
+ ":"
+ port,
e);
} finally {
// if we failed prior to closing the client, close it
if (client != null) {
try {
client.close();
} catch (Throwable t) {
// best effort to close, we do not care about an exception here any more
}
}
}
}
}