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You may already know the old CXF LoggingFeature (org.apache.cxf.feature.LoggingFeature). You added it to a JAXWS endpoint to enable logging for a CXF endpoint at compile time.

While this already helped a lot it was not really enterprise ready. The logging could not be controlled much at runtime and contained too few details. This all changes with the new CXF logging support and the up coming Karaf Decanter.

Logging feature in CXF 3.1.0

In CXF 3.1 this code was moved into a separate module and gathered some new features.

  • Auto logging for existing CXF endpoints
  • Uses slf4j MDC to log meta data separately
  • Adds meta data for Rest calls
  • Adds MD5 message id and exchange id for correlation
  • Simple interface for writing your own appenders
  • Karaf decanter support to log into elastic search

Manual Usage

CXF LoggingFeature
    <jaxws:endpoint ...>
       <bean class="org.apache.cxf.ext.logging.LoggingFeature"/>

Auto logging for existing CXF endpoints in Apache Karaf

Simply install and enable the new logging feature:

Logging feature in karaf
feature:repo-add cxf 3.1.0
feature:install cxf-features-logging
config:property-set -p org.apache.cxf.features.logging enabled true

Then install CXF endpoints like always. For example install the PersonService from the Karaf Tutorial Part 4 - CXF Services in OSGi. The client and endpoint in the example are not equipped with the LoggingFeature. Still the new logging feature will enhance the clients and endpoints and log all SOAP and Rest calls using slf4j. So the logging data will be processed by pax logging and by default end up in your karaf log.

A log entry looks like this:

Sample Log entry
2015-06-08 16:35:54,068 | INFO  | qtp1189348109-73 | REQ_IN                           | 90 - org.apache.cxf.cxf-rt-features-logging - 3.1.0 | <soap:Envelope xmlns:soap=""><soap:Body><ns2:addPerson xmlns:ns2="" xmlns:ns3=""><arg0><id>3</id><name>Test2</name><url></url></arg0></ns2:addPerson></soap:Body></soap:Envelope>

This does not look very informative. You only see that it is an incoming request (REQ_IN) and the SOAP message in the log message. The logging feature provides a lot more information though. You just need to configure the pax logging config to show it.

Slf4j MDC values for meta data

This is the raw logging information you get for a SOAP call:

MDC.content-typetext/xml; charset=UTF-8
MDC.headers{content-type=text/xml; charset=UTF-8, connection=keep-alive, Host=localhost:8181, Content-Length=251, SOAPAction="", User-Agent=Apache CXF 3.1.0, Accept=*/*, Pragma=no-cache, Cache-Control=no-cache}
message<soap:Envelope xmlns:soap=""><soap:Body><ns2:getAll xmlns:ns2=""; xmlns:ns3=""/></soap:Body></soap:Envelope>;

Some things to note:

  • The logger name is <service namespace>.<ServiceName>.<type> karaf by default only cuts it to just the type.
  • A lot of the details are in the MDC values

You need to change your pax logging config to make these visible.

You can use the logger name to fine tune which services you want to log this way. For example set the debug level to WARN for noisy services to avoid that they are logged or log some services to another file.

Message id and exhange id

The messageId allows to uniquely identify messages even if you collect them from several servers. It is also transported over the wire so you can correlate a request sent on one machine with the request received on another machine.

The exchangeId will be the same for an incoming request and the response sent out or on the other side for an outgoing request and the response for it. This allows to correlate request and responses and so follow the conversations.

Simple interface to write your own appenders

Write your own LogSender and set it on the LoggingFeature to do custom logging. You have access to all meta data from the class LogEvent.

So for example you could write your logs to one file per message or to JMS.

Karaf decanter support to write into elastic search

Many people use elastic search for their logging. Fortunately you do not have to write a special LogSender for this purpose. The standard CXF logging feature will already work.

It works like this:

  • CXF sends the messages as slf4j events which are processed by pax logging
  • Karaf Decanter LogCollector attaches to pax logging and sends all log events into the karaf message bus (EventAdmin topics)
  • Karaf Decanter ElasticSearchAppender sends the log events to a configurable elastic search instance

As Decanter also provides features for a local elastic search and kibana instance you are ready to go in just minutes.

Installing Decanter for CXF Logging
feature:repo-add mvn:org.apache.karaf.decanter/apache-karaf-decanter/3.0.0-SNAPSHOT/xml/features
feature:install decanter-collector-log decanter-appender-elasticsearch elasticsearch kibana

After that open a browser at http://localhost:8181/kibana. When decanter is released kibana will be fully set up. At the moment you have to add the logstash dashboard and change the index name to [karaf-]YYYY.MM.DD.

Then you should see your cxf messages like this:

Kibana easily allows to filter for specific services and correlate requests and responses.

This is just a preview of decanter. I will do a more detailed post when the first release is out.


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