/**
* Licensed to Cloudera, Inc. under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Cloudera, Inc. 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 com.cloudera.flume.core;
import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import org.apache.commons.codec.binary.Base64;
import com.cloudera.flume.conf.Context;
import com.cloudera.flume.conf.SinkFactory.SinkDecoBuilder;
import com.google.common.base.Preconditions;
/**
* This decorator calculates a digest of the event body and stores it into the
* specified attribute. It can optionally base 64 encode the digest so that it
* can readily be displayed in text form rather than raw bytes.
*/
public class DigestDecorator<S extends EventSink> extends EventSinkDecorator<S> {
String attr;
MessageDigest stomach;
boolean encodeBase64;
public DigestDecorator(S s, String algorithm, String attr, boolean encodeBase64) {
super(s);
this.attr = attr;
this.encodeBase64 = encodeBase64;
try {
this.stomach = MessageDigest.getInstance(algorithm);
} catch (NoSuchAlgorithmException e) {
throw new IllegalArgumentException(e);
}
}
@Override
public synchronized void append(Event e) throws IOException, InterruptedException {
this.stomach.reset();
this.stomach.update(e.getBody());
byte digest[] = this.stomach.digest();
if (this.encodeBase64) {
digest = Base64.encodeBase64(digest);
}
e.set(this.attr, digest);
super.append(e);
}
public static SinkDecoBuilder builder() {
return new SinkDecoBuilder() {
@Override
public EventSinkDecorator<EventSink> build(Context context,
String... argv) {
Preconditions.checkArgument(argv.length == 2,
"usage: digest(algorithm, attr, [base64=boolean])");
boolean encodeBase64 = false;
String v = context.getValue("base64");
if (v != null) {
encodeBase64 = Boolean.parseBoolean(v);
}
return new DigestDecorator<EventSink>(null, argv[0], argv[1], encodeBase64);
}
};
}
}