Logging configuration in mule

1. Logging Configuration
In Mule

2.  There’s no need to state the importance of debuggers
for developers, and Mule developers are no exception.
The goal of this blog post is to provide you with a few
handy tips for debugging your custom Java code in Mule
Studio.

3.  Through the logging configuration it’s possible to configure what gets
logged, where it gets logged, and how it gets logged.
 Mule internally logs multiple messages along with some specific elements
in the application’s flows.
 The logger component can also be included to output any desired
messages.
 By creating a configuration file, it’s possible to define what kinds of
messages to log, in what way (asynchronously or synchronously), and
where they get logged (To console, To disk or to a database).
Logging Configuration In Mule

4.  For logging Mule uses slf4j.
 Slf4j is a logging facade, that discovers and uses a logging strategy from
the classpath, such as log4j2 or the JDK Logger.
 By Default Mule includes log4j2.
 The configuration used for it is log4j2.xml.
 The Mule server has a log4j2.xml file in the conf directory.
 This file can be customized when running the server in standalone mode.
Logging Configuration In Mule

5.  To view Anypoint Studio logs:
 Error Log :
 Logs can be viewed in Studio by clicking: Anypoint Studio > About Anypoint
Studio > Installation Details > Configuration tab > View Error Log
 Workspace Logs :
 The output from View Error Log is in the workspace’s ’.metadata/.log’ file
 Project Log:
 The logs for the mule application are present in the workspace’s
‘.mule/logs/<project>.log’ file.
Logging Configuration In Mule

6.  Types of logging :
 Synchronous :
 The execution of the thread that is processing the message is interrupted to wait for
the log message to be fully handled before it can continue.
 Asynchronous:
 The logging operation occurs in a separate thread, so the actual processing of your
message won’t be delayed to wait for the logging to complete.
 Note :
 By Default Mule uses the Asynchronous logging in the applications.
Logging Configuration In Mule

7. Synchronous Logging Asynchronous Logging
• Useful when Application logs are
required to be used as audit trails.
• The performance is low, as the
applications waits for the logger
component to complete the
logging.
• brings a substantial improvement
in throughput and latency of
message processing.
• after a system crash, a scenario is
possible where, some actions were
performed but not logged, since
log writing is performed on a
separate thread that runs
independently of other actions.
Logging Configuration In Mule

8.  By default, logging in Mule is done asynchronously and at a level greater
than or equal to INFO.
 Hence it ignores the messages at the DEBUG or TRACE level.
Logging Configuration In Mule

9.  Defining the Logging type, logging level or custom categories can be done
by modifying the log4j2.xml file.
 This file is located at different locations depending on the where the
application is running.
 In Standalone Mule Runtime :
 $MULE_HOME/conf/log4j2.xml
 In Anypoint Studio:
 src/main/resources
Logging Configuration In Mule

10.  If the file is not edited then the default
configuration is assumed for the application.
 The configuration can be overridden at the
domain or the application level.
 Create a custom file at a custom folder location
and point to it in the application’s deployment
properties.
 To point the application to use this file :
 open the application’s mule-deploy.properties file
in src/main/app and add a log.configFile property
with this location specified in it.
 Example :
log.configFile=myCustomFolder/myCustomlog4j2.xm
l
Logging Configuration In Mule

11.  If the deployment property is not set then mule searches for the config
file following child–first pattern as follows :
 Look for a file called log4j2-test.xml in the application
classpath
 Look for a file called log4j2.xml in the application
classpath
 Look for a file called log4j2-test.xml in the domain
classpath
 Look for a file called log4j2.xml in the domain classpath
 Look for a file called log4j2-test.xml in MULE_HOME/conf
 Look for a file called log4j2.xml in MULE_HOME/conf
 Apply default configuration.
Logging Configuration In Mule