Book Image

Apache Flume: Distributed Log Collection for Hadoop

By : Steve Hoffman, Steven Hoffman
Book Image

Apache Flume: Distributed Log Collection for Hadoop

By: Steve Hoffman, Steven Hoffman

Overview of this book

Table of Contents (16 chapters)
Apache Flume: Distributed Log Collection for Hadoop Second Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Interceptors


An interceptor's functionality can be summed up with this method:

public Event intercept(Event event);

A Flume event is passed to it, and it returns a Flume event. It may do nothing, in which case, the same unaltered event is returned. Often, it alters the event in some useful way. If null is returned, the event is dropped.

To add interceptors to a source, simply add the interceptors property to the named source, for example:

agent.sources.s1.interceptors=i1 i2 i3

This defines three interceptors: i1, i2, and i3 on the s1 source for the agent named agent.

Note

Interceptors are run in the order in which they are listed. In the preceding example, i2 will receive the output from i1. Then, i3 will receive the output from i2. Finally, the channel selector receives the output from i3.

Now that we have defined the interceptor by name, we need to specify its type as follows:

agent.sources.s1.interceptors.i1.type=TYPE1
agent.sources.s1.interceptors.i1.additionalProperty1=VALUE
agent.sources.s1...