# Debug using log4j

## Debugging with log4j configurations

Unfortunately setting of logging in the Java Broker is not simply a matter of setting one of WARN,INFO,DEBUG. At some point in the future we may have more BAU logging that falls in to that category but more likely is that we will have a varioius config files that can be swapped in (dynamically) to understand what is going on.

This page will be host to a variety of useful configuration setups that will allow a user or developer to extract only the information they are interested in logging. Each section will be targeted at logging in a particular area and will include a full log4j file that can be used. In addition the logging category elements will be presented and discussed so that the user can create their own file.

Currently the configuration that is available has not been fully documented and as such there are gaps in what is desired and what is available. Some times this is due to the desire to reduce the overhead in message processing, but sometimes it is simply an oversight. Hopefully in future releases the latter will be addressed but care needs to be taken when adding logging to the 'Message Flow' path as this will have performance implications.

### Logging Connection State *Deprecated*

deprecation notice Version 0.6 of the Java broker includes functionality which improves upon these messages and as such enabling status logging would be more beneficial. The configuration file has been left here for assistence with broker versions prior to 0.6.

The goals of this configuration are to record:

- New Connections

- New Consumers

- Identify slow consumers

- Closing of Consumers

- Closing of Connections

An additional goal of this configuration is to minimise any impact to the 'message flow' path. So it should not adversely affect production systems.

    <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
        <appender name="FileAppender" class="org.apache.log4j.FileAppender">
            <param name="File" value="${QPID_WORK}/log/${logprefix}qpid${logsuffix}.log"/>
            <param name="Append" value="false"/>

            <layout class="org.apache.log4j.PatternLayout">
                <param name="ConversionPattern" value="%d %-5p [%t] %C{2} (%F:%L) - %m%n"/>
            </layout>

        </appender>

        <appender name="STDOUT" class="org.apache.log4j.ConsoleAppender">

            <layout class="org.apache.log4j.PatternLayout">
                <param name="ConversionPattern" value="%d %-5p [%t] %C{2} (%F:%L) - %m%n"/>
            </layout>
        </appender>

        <category name="Qpid.Broker">

            <priority value="debug"/>
        </category>

        <!-- Provide warnings to standard output -->
        <category name="org.apache.qpid">
            <priority value="warn"/>
        </category>

        <!-- Connection Logging -->

        <!-- Log details of client starting connection -->
        <category name="org.apache.qpid.server.handler.ConnectionStartOkMethodHandler">
            <priority value="info"/>
        </category>
        <!-- Log details of client closing connection -->
        <category name="org.apache.qpid.server.handler.ConnectionCloseMethodHandler">
            <priority value="info"/>
        </category>
        <!-- Log details of client responding to be asked to closing connection -->

        <category name="org.apache.qpid.server.handler.ConnectionCloseOkMethodHandler">
            <priority value="info"/>
        </category>

        <!-- Consumer Logging -->
        <!-- Provide details of Consumers connecting-->
        <category name="org.apache.qpid.server.handler.BasicConsumeMethodHandler">
            <priority value="debug"/>
        </category>

        <!-- Provide details of Consumers disconnecting, if the call it-->
        <category name="org.apache.qpid.server.handler.BasicCancelMethodHandler">
            <priority value="debug"/>
        </category>
        <!-- Provide details of when a channel closes to attempt to match to the Consume as a Cancel is not always issued-->
        <category name="org.apache.qpid.server.handler.ChannelCloseHandler">
            <priority value="info"/>
        </category>

        <!-- Provide details of Consumers starting to consume-->
        <category name="org.apache.qpid.server.handler.ChannelFlowHandler">
            <priority value="debug"/>
        </category>
        <!-- Provide details of what consumers are going to be consuming-->
        <category name="org.apache.qpid.server.handler.QueueBindHandler">
            <priority value="info"/>
        </category>

        <!-- No way of determining if publish message is returned, client log should show it.-->

        <root>
            <priority value="debug"/>
            <appender-ref ref="STDOUT"/>
            <appender-ref ref="FileAppender"/>
        </root>

    </log4j:configuration>

### Debugging My Application

This is the most often asked for set of configuration. The goals of this configuration are to record:

- New Connections

- New Consumers

- Message Publications

- Message Consumption

- Identify slow consumers

- Closing of Consumers

- Closing of Connections

NOTE: This configuration enables message logging on the 'message flow' path so should only be used were message volume is low. Every message that is sent to the broker will generate at least four logging statements

    <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
        <appender name="FileAppender" class="org.apache.log4j.FileAppender">
            <param name="File" value="${QPID_WORK}/log/${logprefix}qpid${logsuffix}.log"/>
            <param name="Append" value="false"/>

            <layout class="org.apache.log4j.PatternLayout">
                <param name="ConversionPattern" value="%d %-5p [%t] %C{2} (%F:%L) - %m%n"/>
            </layout>

        </appender>

        <appender name="STDOUT" class="org.apache.log4j.ConsoleAppender">

            <layout class="org.apache.log4j.PatternLayout">
                <param name="ConversionPattern" value="%d %-5p [%t] %C{2} (%F:%L) - %m%n"/>
            </layout>
        </appender>

        <category name="Qpid.Broker">

            <priority value="debug"/>
        </category>

        <!-- Provide warnings to standard output -->
        <category name="org.apache.qpid">
            <priority value="warn"/>
        </category>

        <!-- Connection Logging -->

        <!-- Log details of client starting connection -->
        <category name="org.apache.qpid.server.handler.ConnectionStartOkMethodHandler">
            <priority value="info"/>
        </category>
        <!-- Log details of client closing connection -->
        <category name="org.apache.qpid.server.handler.ConnectionCloseMethodHandler">
            <priority value="info"/>
        </category>
        <!-- Log details of client responding to be asked to closing connection -->

        <category name="org.apache.qpid.server.handler.ConnectionCloseOkMethodHandler">
            <priority value="info"/>
        </category>

        <!-- Consumer Logging -->
        <!-- Provide details of Consumers connecting-->
        <category name="org.apache.qpid.server.handler.BasicConsumeMethodHandler">
            <priority value="debug"/>
        </category>

        <!-- Provide details of Consumers disconnecting, if the call it-->
        <category name="org.apache.qpid.server.handler.BasicCancelMethodHandler">
            <priority value="debug"/>
        </category>
        <!-- Provide details of when a channel closes to attempt to match to the Consume as a Cancel is not always issued-->
        <category name="org.apache.qpid.server.handler.ChannelCloseHandler">
            <priority value="info"/>
        </category>

        <!-- Provide details of Consumers starting to consume-->
        <category name="org.apache.qpid.server.handler.ChannelFlowHandler">
            <priority value="debug"/>
        </category>
        <!-- Provide details of what consumers are going to be consuming-->
        <category name="org.apache.qpid.server.handler.QueueBindHandler">
            <priority value="info"/>
        </category>

        <!-- No way of determining if publish message is returned, client log should show it.-->

        <!-- WARNING DO NOT ENABLE THIS IN PRODUCTION -->
        <!-- Will generate minimum one log statements per published message -->
        <!-- Will generate will log receiving of all body frame, count will vary on size of message.-->
        <!-- Empty Message = no body, Body is up to 64kb of data -->
        <!-- Will generate three log statements per recevied message -->

        <!-- Log messages flow-->
        <category name="org.apache.qpid.server.AMQChannel">

            <priority value="debug"/>
        </category>

        <root>
            <priority value="debug"/>
            <appender-ref ref="STDOUT"/>
            <appender-ref ref="FileAppender"/>
        </root>

    </log4j:configuration>