/**
* 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.avro.tool;
import java.io.InputStream;
import java.io.PrintStream;
import java.util.List;
import joptsimple.OptionParser;
import joptsimple.OptionSet;
import joptsimple.OptionSpec;
import org.apache.avro.file.DataFileReader;
import org.apache.avro.generic.GenericDatumReader;
import org.apache.avro.mapred.FsInput;
/** Reads a data file to get its metadata. */
public class DataFileGetMetaTool implements Tool {
@Override
public String getName() {
return "getmeta";
}
@Override
public String getShortDescription() {
return "Prints out the metadata of an Avro data file.";
}
@Override
public int run(InputStream stdin, PrintStream out, PrintStream err,
List<String> args) throws Exception {
OptionParser p = new OptionParser();
OptionSpec<String> keyOption =
p.accepts("key", "Metadata key")
.withOptionalArg()
.ofType(String.class);
OptionSet opts = p.parse(args.toArray(new String[0]));
String keyName = keyOption.value(opts);
List<String> nargs = opts.nonOptionArguments();
if (nargs.size() != 1) {
err.println("Expected 1 arg: input_file");
p.printHelpOn(err);
return 1;
}
FsInput in = Util.openSeekableFromFS(args.get(0));
DataFileReader<Void> reader =
new DataFileReader<Void>(in, new GenericDatumReader<Void>());
if (keyName != null) {
byte[] value = reader.getMeta(keyName);
if (value != null) {
out.write(value, 0, value.length);
out.println();
}
} else {
List<String> keys = reader.getMetaKeys();
for (String key : keys) {
out.print(escapeKey(key));
out.print('\t');
byte[] value = reader.getMeta(key);
out.write(value, 0, value.length);
out.println();
}
}
return 0;
}
// escape TAB, NL and CR in keys, so that output can be reliably parsed
static String escapeKey(String key) {
key = key.replace("\\","\\\\"); // escape backslashes first
key = key.replace("\t","\\t"); // TAB
key = key.replace("\n","\\n"); // NL
key = key.replace("\r","\\r"); // CR
return key;
}
}