/**
* 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 static org.apache.flume.interceptor.RegexFilteringInterceptor.Constants.DEFAULT_EXCLUDE_EVENTS;
import static org.apache.flume.interceptor.RegexFilteringInterceptor.Constants.DEFAULT_REGEX;
import static org.apache.flume.interceptor.RegexFilteringInterceptor.Constants.EXCLUDE_EVENTS;
import static org.apache.flume.interceptor.RegexFilteringInterceptor.Constants.REGEX;
import java.util.List;
import java.util.regex.Pattern;
import org.apache.flume.Context;
import org.apache.flume.Event;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.common.collect.Lists;
/**
* Interceptor that filters events selectively based on a configured regular
* expression matching against the event body.
*
* This supports either include- or exclude-based filtering. A given
* interceptor can only perform one of these functions, but multiple
* interceptor can be chained together to create more complex
* inclusion/exclusion patterns. If include-based filtering is configured, then
* all events matching the supplied regular expression will be passed through
* and all events not matching will be ignored. If exclude-based filtering is
* configured, than all events matching will be ignored, and all other events
* will pass through.
*
* Note that all regular expression matching occurs through Java's built in
* java.util.regex package.
*
* Properties:<p>
*
* regex: Regular expression for matching excluded events.
* (default is ".*")<p>
*
* excludeEvents: If true, a regex match determines events to exclude,
* otherwise a regex determines events to include
* (default is false)<p>
*
* Sample config:<p>
*
* <code>
* 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<p>
* agent.sources.r1.interceptors.i1.regex = (WARNING)|(ERROR)|(FATAL)<p>
* </code>
*
*/
public class RegexFilteringInterceptor implements Interceptor {
private static final Logger logger = LoggerFactory
.getLogger(StaticInterceptor.class);
private final Pattern regex;
private final boolean excludeEvents;
/**
* Only {@link RegexFilteringInterceptor.Builder} can build me
*/
private RegexFilteringInterceptor(Pattern regex, boolean excludeEvents) {
this.regex = regex;
this.excludeEvents = excludeEvents;
}
@Override
public void initialize() {
// no-op
}
@Override
/**
* Returns the event if it passes the regular expression filter and null
* otherwise.
*/
public Event intercept(Event event) {
// We've already ensured here that at most one of includeRegex and
// excludeRegex are defined.
if (!excludeEvents) {
if (regex.matcher(new String(event.getBody())).find()) {
return event;
} else {
return null;
}
} else {
if (regex.matcher(new String(event.getBody())).find()) {
return null;
} else {
return event;
}
}
}
/**
* Returns the set of events which pass filters, according to
* {@link #intercept(Event)}.
* @param events
* @return
*/
@Override
public List<Event> intercept(List<Event> events) {
List<Event> out = Lists.newArrayList();
for (Event event : events) {
Event outEvent = intercept(event);
if (outEvent != null) {
out.add(outEvent);
}
}
return out;
}
@Override
public void close() {
// no-op
}
/**
* Builder which builds new instance of the StaticInterceptor.
*/
public static class Builder implements Interceptor.Builder {
private Pattern regex;
private boolean excludeEvents;
@Override
public void configure(Context context) {
String regexString = context.getString(REGEX, DEFAULT_REGEX);
regex = Pattern.compile(regexString);
excludeEvents = context.getBoolean(EXCLUDE_EVENTS,
DEFAULT_EXCLUDE_EVENTS);
}
@Override
public Interceptor build() {
logger.info(String.format(
"Creating RegexFilteringInterceptor: regex=%s,excludeEvents=%s",
regex, excludeEvents));
return new RegexFilteringInterceptor(regex, excludeEvents);
}
}
public static class Constants {
public static final String REGEX = "regex";
public static final String DEFAULT_REGEX = ".*";
public static final String EXCLUDE_EVENTS = "excludeEvents";
public static final boolean DEFAULT_EXCLUDE_EVENTS = false;
}
}