List the available hadoop codecs

list_hadoop_codecs.sh

#!/usr/bin/env bash

# list_hadoop_codecs.sh
#
# USAGE:
# curl -sL https://gist.github.com/chetan/6524829/raw/list_hadoop_codecs.sh | bash

# make sure hadoop is avail
if [[ -z `which hadoop 2>/dev/null` ]]; then
  echo "hadoop command not found!"
  exit 1
fi

hadoop checknative 2>/dev/null


CP=$(hadoop classpath)
JLIB="-Djava.library.path=/usr/lib/hadoop/lib/native:/usr/lib/hbase/lib/native/Linux-amd64-64"

J=$(cat <<- EOF
import java.util.List;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.compress.CompressionCodec;
import org.apache.hadoop.io.compress.CompressionCodecFactory;

public class ListCodecs {
  public static void main(String[] args) throws Throwable {
    List<Class<? extends CompressionCodec>> codecClasses = CompressionCodecFactory.getCodecClasses(new Configuration());
    System.out.println("\navailable codecs:\n");
    for (Class<? extends CompressionCodec> clazz : codecClasses) {
      String str = "";
      String codecName = clazz.getSimpleName();
      if (codecName.endsWith("Codec")) {
        codecName = codecName.substring(0, codecName.length() - "Codec".length());
        str = codecName.toLowerCase();
      }
      String ext = clazz.newInstance().getDefaultExtension();
      str = str + "\t\t" + ext + "\t" + (ext.length()<8 ? "\t":"") + clazz.getName();
      System.out.println(str);
    }
    System.out.println("\n");
  }
}
EOF
)

cd /tmp
echo $J > ListCodecs.java
javac -cp $CP ListCodecs.java
java $JLIB -cp .:$CP ListCodecs 2>/dev/null
rm -f ListCodecs.*

sample_output.txt

$ curl -sL https://gist.github.com/chetan/6524829/raw/list_hadoop_codecs.sh | bash
Native library checking:
hadoop: true
zlib:   true
snappy: true
lz4:    true

available codecs:

bzip2           .bz2            org.apache.hadoop.io.compress.BZip2Codec
default         .deflate        org.apache.hadoop.io.compress.DefaultCodec
deflate         .deflate        org.apache.hadoop.io.compress.DeflateCodec
gzip            .gz             org.apache.hadoop.io.compress.GzipCodec
lz4             .lz4            org.apache.hadoop.io.compress.Lz4Codec
snappy          .snappy         org.apache.hadoop.io.compress.SnappyCodec