org.apache.flume.interceptor.HostInterceptor Maven / Gradle / Ivy
/**
* 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.net.InetAddress;
import java.net.UnknownHostException;
import java.util.List;
import java.util.Map;
import org.apache.flume.Context;
import org.apache.flume.Event;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import static org.apache.flume.interceptor.HostInterceptor.Constants.*;
/**
* Simple Interceptor class that sets the host name or IP on all events
* that are intercepted.
* The host header is named host and its format is either the FQDN
* or IP of the host on which this interceptor is run.
*
*
* Properties:
*
* preserveExisting: Whether to preserve an existing value for 'host'
* (default is false)
*
* useIP: Whether to use IP address or fully-qualified hostname for 'host'
* header value (default is true)
*
* hostHeader: Specify the key to be used in the event header map for the
* host name. (default is "host")
*
* Sample config:
*
*
* agent.sources.r1.channels = c1
* agent.sources.r1.type = SEQ
* agent.sources.r1.interceptors = i1
* agent.sources.r1.interceptors.i1.type = host
* agent.sources.r1.interceptors.i1.preserveExisting = true
* agent.sources.r1.interceptors.i1.useIP = false
* agent.sources.r1.interceptors.i1.hostHeader = hostname
*
*
*/
public class HostInterceptor implements Interceptor {
private static final Logger logger = LoggerFactory
.getLogger(HostInterceptor.class);
private final boolean preserveExisting;
private final String header;
private String host = null;
/**
* Only {@link HostInterceptor.Builder} can build me
*/
private HostInterceptor(boolean preserveExisting,
boolean useIP, String header) {
this.preserveExisting = preserveExisting;
this.header = header;
InetAddress addr;
try {
addr = InetAddress.getLocalHost();
if (useIP) {
host = addr.getHostAddress();
} else {
host = addr.getCanonicalHostName();
}
} catch (UnknownHostException e) {
logger.warn("Could not get local host address. Exception follows.", e);
}
}
@Override
public void initialize() {
// no-op
}
/**
* Modifies events in-place.
*/
@Override
public Event intercept(Event event) {
Map headers = event.getHeaders();
if (preserveExisting && headers.containsKey(header)) {
return event;
}
if(host != null) {
headers.put(header, host);
}
return event;
}
/**
* Delegates to {@link #intercept(Event)} in a loop.
* @param events
* @return
*/
@Override
public List intercept(List events) {
for (Event event : events) {
intercept(event);
}
return events;
}
@Override
public void close() {
// no-op
}
/**
* Builder which builds new instances of the HostInterceptor.
*/
public static class Builder implements Interceptor.Builder {
private boolean preserveExisting = PRESERVE_DFLT;
private boolean useIP = USE_IP_DFLT;
private String header = HOST;
@Override
public Interceptor build() {
return new HostInterceptor(preserveExisting, useIP, header);
}
@Override
public void configure(Context context) {
preserveExisting = context.getBoolean(PRESERVE, PRESERVE_DFLT);
useIP = context.getBoolean(USE_IP, USE_IP_DFLT);
header = context.getString(HOST_HEADER, HOST);
}
}
public static class Constants {
public static String HOST = "host";
public static String PRESERVE = "preserveExisting";
public static boolean PRESERVE_DFLT = false;
public static String USE_IP = "useIP";
public static boolean USE_IP_DFLT = true;
public static String HOST_HEADER = "hostHeader";
}
}