Chapter 18. Logging


AMQ Broker uses the Apache Log4j 2 logging utility to provide message logging. When you install a broker, it has a default Log4j 2 configuration in the <broker_instance_dir>/etc/log4j2.properties file. With the default configuration, the loggers write to both the console and to a file.

The loggers available in AMQ Broker are shown in the following table.

Table 18.1. AMQ Broker loggers
LoggerDescription

org.apache.activemq.artemis.core.server

Logs the broker core

org.apache.activemq.artemis.journal

Logs Journal calls

org.apache.activemq.artemis.utils

Logs utility calls

org.apache.activemq.artemis.jms

Logs JMS calls

org.apache.activemq.artemis.integration.bootstrap

Logs bootstrap calls

org.apache.activemq.audit.base

Logs access to all JMX object methods

org.apache.activemq.audit.message

Logs message operations such as production, consumption, and browsing of messages

org.apache.activemq.audit.resource

Logs authentication events, creation or deletion of broker resources from JMX or the AMQ Broker management console, and browsing of messages in the management console

18.1. Changing the logging level

You can configure the logging level for each logger in the <logger name>.level line after the logger name, as shown in the following example for the apache.activemq.artemis.core.server logger:

logger.artemis_server.name=org.apache.activemq.artemis.core.server
logger.artemis_server.level=INFO

The default logging level for audit loggers is OFF, which means that logging is disabled. The default logging level for the other loggers available in AMQ Broker is INFO. For information on the logging levels available in Log4j 2, see the Log4j 2 documentation.

18.2. Enabling audit logging

Three audit loggers are available for you to enable; a base audit logger, a message audit logger, and a resource audit logger.

Base audit logger (org.apache.activemq.audit.base)
Logs access to all JMX object methods, such as creation and deletion of addresses and queues. The log does not indicate whether these operations succeeded or failed.
Message audit logger (org.apache.activemq.audit.message)
Logs message-related broker operations, such as production, consumption, or browsing of messages.
Resource audit logger (org.apache.activemq.audit.resource)
Logs authentication success or failure from clients, routes, and the AMQ Broker management console. Also logs creation, update, or deletion of queues from either JMX or the management console, and browsing of messages in the management console.

You can enable each audit logger independently of the others. By default, the logging level is set to OFF, which means logging is disabled, for each audit logger. To enable one of the audit loggers, change the logging level from OFF to INFO. For example:

logger.audit_base = INFO, audit_log_file
Note

INFO is the only available logging level for the logger.org.apache.activemq.audit.base, logger.org.apache.activemq.audit.message, and logger.org.apache.activemq.audit.resource audit loggers.

Important

The message audit logger runs on a performance-intensive path on the broker. Enabling the logger might negatively affect the performance of the broker, particularly if the broker is running under a high messaging load. Red Hat recommends that you do not enable audit logging on messaging systems where high throughput is required.

18.3. Client or embedded server logging

If you want to enable logging on a client, you need to include a logging implementation in your application that supports the SLF4J facade. If you are using Maven, add the following dependencies for Log4j 2:

<dependency>
   <groupId>org.apache.activemq</groupId>
   <artifactId>artemis-jms-client</artifactId>
   <version>2.28.0</version>
</dependency>
<dependency>
   <groupId>org.apache.logging.log4j</groupId>
   <artifactId>log4j-slf4j-impl</artifactId>
   <version>2.19.0</version>
</dependency>

You can supply the Log4j 2 configuration in a log4j2.properties file in the classpath. Or, you can specify a custom configuration file by using the log4j2.configurationFile system property. For example:

-Dlog4j2.configurationFile=file:///path/to/custom-log4j2-config.properties

The following is an example log4j2.properties file for a client:

# Log4J 2 configuration

# Monitor config file every X seconds for updates
monitorInterval = 5

rootLogger = INFO, console, log_file

logger.activemq.name=org.apache.activemq
logger.activemq.level=INFO

# Console appender
appender.console.type=Console
appender.console.name=console
appender.console.layout.type=PatternLayout
appender.console.layout.pattern=%d %-5level [%logger] %msg%n

# Log file appender
appender.log_file.type = RollingFile
appender.log_file.name = log_file
appender.log_file.fileName = log/application.log
appender.log_file.filePattern = log/application.log.%d{yyyy-MM-dd}
appender.log_file.layout.type = PatternLayout
appender.log_file.layout.pattern = %d %-5level [%logger] %msg%n
appender.log_file.policies.type = Policies
appender.log_file.policies.cron.type = CronTriggeringPolicy
appender.log_file.policies.cron.schedule = 0 0 0 * * ?
appender.log_file.policies.cron.evaluateOnStartup = true

18.4. AMQ Broker plugin support

AMQ supports custom plugins. You can use plugins to log information about many different types of events that would otherwise only be available through debug logs. Multiple plugins can be registered, tied, and executed together. The plugins are executed based on the order of the registration, that is, the first plugin registered is always executed first.

You can create custom plugins and implement them using the ActiveMQServerPlugin interface. This interface ensures that the plugin is on the classpath, and is registered with the broker. As all the interface methods are implemented by default, you have to add only the required behavior that needs to be implemented.

18.4.1. Adding plugins to the class path

Add the custom created broker plugins to the broker runtime by adding the relevant .jar files to the <broker_instance_dir>/lib directory.

If you are using an embedded system, place the .jar file under the regular class path of your embedded application.

18.4.2. Registering a plugin

You must register a plugin by adding the broker-plugins element in the broker.xml configuration file. You can specify the plugin configuration value using the property child elements. These properties are read and passed into the plugin’s init (Map<String, String>) operation after the plugin has been instantiated.

<broker-plugins>
   <broker-plugin class-name="some.plugin.UserPlugin">
      <property key="property1" value="val_1" />
      <property key="property2" value="val_2" />
   </broker-plugin>
 </broker-plugins>

18.4.3. Registering a plugin programmatically

To register a plugin programmatically, use the registerBrokerPlugin() method and pass in a new instance of your plugin. The example below shows the registration of the UserPlugin plugin:

Configuration config = new ConfigurationImpl();

config.registerBrokerPlugin(new UserPlugin());

18.4.4. Logging specific events

By default, AMQ broker provides the LoggingActiveMQServerPlugin plugin to log specific broker events. The LoggingActiveMQServerplugin plugin is commented-out by default and does not log any information.

The following table describes each plugin property. Set a configuration property value to true to log events.

Table 18.2. LoggingActiveMQServerPlugin plugin properties

Property

Description

LOG_CONNECTION_EVENTS

Logs information when a connection is created or destroyed.

LOG_SESSION_EVENTS

Logs information when a session is created or closed.

LOG_CONSUMER_EVENTS

Logs information when a consumer is created or closed.

LOG_DELIVERING_EVENTS

Logs information when message is delivered to a consumer and when a message is acknowledged by a consumer.

LOG_SENDING_EVENTS

Logs information when a message has been sent to an address and when a message has been routed within the broker.

LOG_INTERNAL_EVENTS

Logs information when a queue created or destroyed, when a message is expired, when a bridge is deployed, and when a critical failure occurs.

LOG_ALL_EVENTS

Logs information for all the above events.

To configure the LoggingActiveMQServerPlugin plugin to log connection events, uncomment the <broker-plugins> section in the broker.xml configuration file. The value of all the events is set to true in the commented default example.

<configuration ...>
...
<!-- Uncomment the following if you want to use the Standard LoggingActiveMQServerPlugin plugin to log in events -->
           <broker-plugins>
         <broker-plugin class-name="org.apache.activemq.artemis.core.server.plugin.impl.LoggingActiveMQServerPlugin">
            <property key="LOG_ALL_EVENTS" value="true"/>
            <property key="LOG_CONNECTION_EVENTS" value="true"/>
            <property key="LOG_SESSION_EVENTS" value="true"/>
            <property key="LOG_CONSUMER_EVENTS" value="true"/>
            <property key="LOG_DELIVERING_EVENTS" value="true"/>
            <property key="LOG_SENDING_EVENTS" value="true"/>
            <property key="LOG_INTERNAL_EVENTS" value="true"/>
         </broker-plugin>
      </broker-plugins>
...
</configuration>

When you change the configuration parameters inside the <broker-plugins> section, you must restart the broker to reload the configuration updates. These configuration changes are not reloaded based on the configuration-file-refresh-period setting.

When the log level is set to INFO, an entry is logged after the event has occurred. If the log level is set to DEBUG, log entries are generated for both before and after the event, for example, beforeCreateConsumer() and afterCreateConsumer(). If the log Level is set to DEBUG, the logger logs more information for a notification, when available.

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