/**
* 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.flume.interceptor;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.lang.StringUtils;
import org.apache.flume.Context;
import org.apache.flume.Event;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.common.base.Charsets;
import com.google.common.base.Preconditions;
import com.google.common.base.Throwables;
import com.google.common.collect.Lists;
/**
* Interceptor that extracts matches using a specified regular expression and
* appends the matches to the event headers using the specified serializers</p>
* Note that all regular expression matching occurs through Java's built in
* java.util.regex package</p>. Properties:
* <p>
* regex: The regex to use
* <p>
* serializers: Specifies the group the serializer will be applied to, and the
* name of the header that will be added. If no serializer is specified for a
* group the default {@link RegexExtractorInterceptorPassThroughSerializer} will
* be used
* <p>
* Sample config:
* <p>
* agent.sources.r1.channels = c1
* <p>
* agent.sources.r1.type = SEQ
* <p>
* agent.sources.r1.interceptors = i1
* <p>
* agent.sources.r1.interceptors.i1.type = REGEX_EXTRACTOR
* <p>
* agent.sources.r1.interceptors.i1.regex = (WARNING)|(ERROR)|(FATAL)
* <p>
* agent.sources.r1.interceptors.i1.serializers = s1 s2
* agent.sources.r1.interceptors.i1.serializers.s1.type = com.blah.SomeSerializer
* agent.sources.r1.interceptors.i1.serializers.s1.name = warning
* agent.sources.r1.interceptors.i1.serializers.s2.type =
* org.apache.flume.interceptor.RegexExtractorInterceptorTimestampSerializer
* agent.sources.r1.interceptors.i1.serializers.s2.name = error
* agent.sources.r1.interceptors.i1.serializers.s2.dateFormat = yyyy-MM-dd
* </p>
* <pre>
* Example 1:
* </p>
* EventBody: 1:2:3.4foobar5</p> Configuration:
* agent.sources.r1.interceptors.i1.regex = (\\d):(\\d):(\\d)
* </p>
* agent.sources.r1.interceptors.i1.serializers = s1 s2 s3
* agent.sources.r1.interceptors.i1.serializers.s1.name = one
* agent.sources.r1.interceptors.i1.serializers.s2.name = two
* agent.sources.r1.interceptors.i1.serializers.s3.name = three
* </p>
* results in an event with the the following
*
* body: 1:2:3.4foobar5 headers: one=>1, two=>2, three=3
*
* Example 2:
*
* EventBody: 1:2:3.4foobar5
*
* Configuration: agent.sources.r1.interceptors.i1.regex = (\\d):(\\d):(\\d)
* <p>
* agent.sources.r1.interceptors.i1.serializers = s1 s2
* agent.sources.r1.interceptors.i1.serializers.s1.name = one
* agent.sources.r1.interceptors.i1.serializers.s2.name = two
* <p>
*
* results in an event with the the following
*
* body: 1:2:3.4foobar5 headers: one=>1, two=>2
* </pre>
*/
public class RegexExtractorInterceptor implements Interceptor {
static final String REGEX = "regex";
static final String SERIALIZERS = "serializers";
private static final Logger logger = LoggerFactory
.getLogger(RegexExtractorInterceptor.class);
private final Pattern regex;
private final List<NameAndSerializer> serializers;
private RegexExtractorInterceptor(Pattern regex,
List<NameAndSerializer> serializers) {
this.regex = regex;
this.serializers = serializers;
}
@Override
public void initialize() {
// NO-OP...
}
@Override
public void close() {
// NO-OP...
}
@Override
public Event intercept(Event event) {
Matcher matcher = regex.matcher(
new String(event.getBody(), Charsets.UTF_8));
Map<String, String> headers = event.getHeaders();
if (matcher.find()) {
for (int group = 0, count = matcher.groupCount(); group < count; group++) {
int groupIndex = group + 1;
if (groupIndex > serializers.size()) {
if (logger.isDebugEnabled()) {
logger.debug("Skipping group {} to {} due to missing serializer",
group, count);
}
break;
}
NameAndSerializer serializer = serializers.get(group);
if (logger.isDebugEnabled()) {
logger.debug("Serializing {} using {}", serializer.headerName,
serializer.serializer);
}
headers.put(serializer.headerName,
serializer.serializer.serialize(matcher.group(groupIndex)));
}
}
return event;
}
@Override
public List<Event> intercept(List<Event> events) {
List<Event> intercepted = Lists.newArrayListWithCapacity(events.size());
for (Event event : events) {
Event interceptedEvent = intercept(event);
if (interceptedEvent != null) {
intercepted.add(interceptedEvent);
}
}
return intercepted;
}
public static class Builder implements Interceptor.Builder {
private Pattern regex;
private List<NameAndSerializer> serializerList;
private final RegexExtractorInterceptorSerializer defaultSerializer =
new RegexExtractorInterceptorPassThroughSerializer();
@Override
public void configure(Context context) {
String regexString = context.getString(REGEX);
Preconditions.checkArgument(!StringUtils.isEmpty(regexString),
"Must supply a valid regex string");
regex = Pattern.compile(regexString);
regex.pattern();
regex.matcher("").groupCount();
configureSerializers(context);
}
private void configureSerializers(Context context) {
String serializerListStr = context.getString(SERIALIZERS);
Preconditions.checkArgument(!StringUtils.isEmpty(serializerListStr),
"Must supply at least one name and serializer");
String[] serializerNames = serializerListStr.split("\\s+");
Context serializerContexts =
new Context(context.getSubProperties(SERIALIZERS + "."));
serializerList = Lists.newArrayListWithCapacity(serializerNames.length);
for (String serializerName : serializerNames) {
Context serializerContext = new Context(
serializerContexts.getSubProperties(serializerName + "."));
String type = serializerContext.getString("type", "DEFAULT");
String name = serializerContext.getString("name");
Preconditions.checkArgument(!StringUtils.isEmpty(name),
"Supplied name cannot be empty.");
if ("DEFAULT".equals(type)) {
serializerList.add(new NameAndSerializer(name, defaultSerializer));
} else {
serializerList.add(new NameAndSerializer(name, getCustomSerializer(
type, serializerContext)));
}
}
}
private RegexExtractorInterceptorSerializer getCustomSerializer(
String clazzName, Context context) {
try {
RegexExtractorInterceptorSerializer serializer = (RegexExtractorInterceptorSerializer) Class
.forName(clazzName).newInstance();
serializer.configure(context);
return serializer;
} catch (Exception e) {
logger.error("Could not instantiate event serializer.", e);
Throwables.propagate(e);
}
return defaultSerializer;
}
@Override
public Interceptor build() {
Preconditions.checkArgument(regex != null,
"Regex pattern was misconfigured");
Preconditions.checkArgument(serializerList.size() > 0,
"Must supply a valid group match id list");
return new RegexExtractorInterceptor(regex, serializerList);
}
}
static class NameAndSerializer {
private final String headerName;
private final RegexExtractorInterceptorSerializer serializer;
public NameAndSerializer(String headerName,
RegexExtractorInterceptorSerializer serializer) {
this.headerName = headerName;
this.serializer = serializer;
}
}
}