org.apache.druid.tasklogs.TaskLogStreamer.java Source code

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Here is the source code for org.apache.druid.tasklogs.TaskLogStreamer.java

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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.druid.tasklogs;

import com.google.common.base.Optional;
import com.google.common.io.ByteSource;
import org.apache.druid.guice.annotations.ExtensionPoint;

import java.io.IOException;

/**
 * Something that knows how to stream logs for tasks.
 */
@ExtensionPoint
public interface TaskLogStreamer {
    /**
     * Stream log for a task.
     *
     * @param offset If zero, stream the entire log. If positive, attempt to read from this position onwards. If
     *               negative, attempt to read this many bytes from the end of the file (like <tt>tail -n</tt>).
     *
     * @return input supplier for this log, if available from this provider
     */
    Optional<ByteSource> streamTaskLog(String taskid, long offset) throws IOException;

    default Optional<ByteSource> streamTaskReports(final String taskid) throws IOException {
        return Optional.absent();
    }
}