content: /*
   * 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.kafka.connect.file;
  
  import org.apache.kafka.clients.consumer.OffsetAndMetadata;
  import org.apache.kafka.common.TopicPartition;
  import org.apache.kafka.common.config.AbstractConfig;
  import org.apache.kafka.connect.errors.ConnectException;
  import org.apache.kafka.connect.sink.SinkRecord;
  import org.apache.kafka.connect.sink.SinkTask;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.io.PrintStream;
  import java.nio.charset.StandardCharsets;
  import java.nio.file.Files;
  import java.nio.file.Paths;
  import java.nio.file.StandardOpenOption;
  import java.util.Collection;
  import java.util.Map;
  
  /**
   * FileStreamSinkTask writes records to stdout or a file.
   */
  public class FileStreamSinkTask extends SinkTask {
      private static final Logger log = LoggerFactory.getLogger(FileStreamSinkTask.class);
  
      private String filename;
      private PrintStream outputStream;
  
      public FileStreamSinkTask() {
      }
  
      // for testing
      public FileStreamSinkTask(PrintStream outputStream) {
          filename = null;
          this.outputStream = outputStream;
      }
  
      @Override
      public String version() {
          return new FileStreamSinkConnector().version();
      }
  
      @Override
      public void start(Map<String, String> props) {
          AbstractConfig config = new AbstractConfig(FileStreamSinkConnector.CONFIG_DEF, props);
          filename = config.getString(FileStreamSinkConnector.FILE_CONFIG);
          if (filename == null || filename.isEmpty()) {
              outputStream = System.out;
          } else {
              try {
                  outputStream = new PrintStream(
                      Files.newOutputStream(Paths.get(filename), StandardOpenOption.CREATE, StandardOpenOption.APPEND),
                      false,
                      StandardCharsets.UTF_8);
              } catch (IOException e) {
                  throw new ConnectException("Couldn't find or create file '" + filename + "' for FileStreamSinkTask", e);
              }
          }
      }
  
      @Override
      public void put(Collection<SinkRecord> sinkRecords) {
          for (SinkRecord record : sinkRecords) {
              log.trace("Writing line to {}: {}", logFilename(), record.value());
              outputStream.println(record.value());
          }
      }
  
      @Override
      public void flush(Map<TopicPartition, OffsetAndMetadata> offsets) {
          log.trace("Flushing output stream for {}", logFilename());
          outputStream.flush();
      }
  
      @Override
      public void stop() {
          if (outputStream != null && outputStream != System.out)
              outputStream.close();
      }
  
      private String logFilename() {
          return filename == null ? "stdout" : filename;
      }
  }
  