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From "Joe Ellis (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HADOOP-13870) Incorrect behavior of copyFromLocalFile on implementations of FilterFileSystem
Date Wed, 07 Dec 2016 07:49:58 GMT
Joe Ellis created HADOOP-13870:
----------------------------------

             Summary: Incorrect behavior of copyFromLocalFile on implementations of FilterFileSystem
                 Key: HADOOP-13870
                 URL: https://issues.apache.org/jira/browse/HADOOP-13870
             Project: Hadoop Common
          Issue Type: Bug
          Components: fs
            Reporter: Joe Ellis


This may be an incorrect assumption on my part, but it was my belief that overriding the create
method on a FilterFileSystem was sufficient to intercept all calls that would write data through
the FileSystem. This is apparently not true because calling copyFromLocalFile on the FilterFileSystem
eventually invokes the create method on the wrapped FileSystem. I would expect open ->
create -> copy(opened, created) to be functionally equivalent to copyFromLocal when using
the same input and output paths, but this is not the case.

{code:java}
import java.io.IOException;
import java.net.URI;
import java.nio.charset.StandardCharsets;
import org.apache.commons.io.IOUtils;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.FilterFileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.util.Progressable;
import org.junit.Before;
import org.junit.Test;

public final class CopyFromLocalFileTest {

    private static final Path DATA_PATH = new Path("file:///tmp/test_in");
    private static final Path OUT_PATH = new Path("file:///tmp/test_out");

    private FileSystem localFs;
    private FileSystem wrappedFs;

    @Before
    public void before() throws IOException {
        localFs = FileSystem.get(URI.create("file:///"), new Configuration());
        wrappedFs = new FailingFileSystem(localFs);

        FSDataOutputStream tmpFile = localFs.create(DATA_PATH);
        byte[] bytes = "data".getBytes(StandardCharsets.UTF_8);
        tmpFile.write(bytes);
        tmpFile.close();
    }

    @Test
    public void test_correct() throws IOException {
        FSDataInputStream in = wrappedFs.open(DATA_PATH);
        FSDataOutputStream out = wrappedFs.create(OUT_PATH);
        IOUtils.copy(in, out);
    }

    @Test
    public void test_incorrect() throws IOException {
        wrappedFs.copyFromLocalFile(DATA_PATH, OUT_PATH);
    }

    private static final class FailingFileSystem extends FilterFileSystem {

        public FailingFileSystem(FileSystem fs) {
            super(fs);
        }

        @Override
        public FSDataOutputStream create(Path f, FsPermission permission, boolean overwrite,
int bufferSize,
                short replication, long blockSize, Progressable progress) throws IOException
{
            throw new IOException("fail");
        }

    }
}
{code}



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