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Logging and Tracing in Tuscany

Timing

Standalone Runtime Example

WebSphere Example

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Following the approach of AspectJ, Tuscany provide two concrete aspects for logging and tracing. org.apache.tuscany.sca.aspectj.LoggingAspect provides logging for methods, constructors, and static initializers in Tuscany. org.apache.tuscany.sca.aspectj.SimpleTracingAspect provide tracing into user methods, constructors, and static initializers. Both provide detailed information when an Exception or Throwable is thrown by the Tuscany runtime or user SCA program.

Both LoggingAspect and SimpleTracingAspect are run by naming the AspectJ runtime agent aspectjweaver.jar at launch. This is shown in the command line example above, and an example is provided in launcher.bat int he tracing-aspectj module.

The runtime configuration file aop.xml has references to these aspects. Uncomment one or both of these in aop.xml to run with this logging enabled. Following is an example logging run with the verbose weaver option specified. Note the verbose output of class names, build times, etc. The logging statements too are quite verbose stating the name of the join point, the point cut, and various signatures and arguments.

[INFO] Configured Artifact: org.aspectj:aspectjweaver:1.6.1:jar
[INFO] Copying aspectjweaver-1.6.1.jar to E:\t\java\sca\modules\tracing-aspectj\target\dependency\aspectjweaver-1.6.1.jar
[AppClassLoader@92e78c] info AspectJ Weaver Version 1.6.1 built on Thursday Jul 3, 2008 at 18:35:41 GMT
[AppClassLoader@92e78c] info register classloader sun.misc.Launcher$AppClassLoader@92e78c
[AppClassLoader@92e78c] info using configuration /E:/t/java/sca/modules/tracing-aspectj/target/classes/META-INF/aop.xml
[AppClassLoader@92e78c] info register aspect org.apache.tuscany.sca.aspectj.LoggingAspect
[AppClassLoader@92e78c] info define aspect org.apache.tuscany.sca.aspectj.UserTimingAspect

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 T E S T S
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Logging Before anyMethodCall jp.getSignature=SCANodeFactory org.apache.tuscany.sca.node.SCANodeFactory.newInstance()
Logging Before anyConstructor jp.getSignature=org.apache.tuscany.sca.extensibility.ServiceDiscovery()
Logging Before anyConstructor jp.getSignature=org.apache.tuscany.sca.extensibility.ServiceDiscovery.1(ServiceDiscovery, Class)
Logging Before anyConstructor jp.getArgs=[org.apache.tuscany.sca.extensibility.ServiceDiscovery@ceb6dd, class org.apache.tuscany.sca.node.SCANodeFactory]
Logging Before anyMethodCall jp.getSignature=ServiceDiscoverer org.apache.tuscany.sca.extensibility.ServiceDiscovery.getServiceDiscoverer()
Logging Before anyConstructor jp.getSignature=org.apache.tuscany.sca.extensibility.ContextClassLoaderServiceDiscoverer()
Logging AfterReturning anyMethodCall jp=call(ServiceDiscoverer org.apache.tuscany.sca.extensibility.ServiceDiscovery.getServiceDiscoverer()), result=org.apache.tuscany.sca.extensibility.ContextClassLoaderServiceDiscoverer@17574b9
Logging Before anyMethodCall jp.getSignature=Set org.apache.tuscany.sca.extensibility.ServiceDiscoverer.discover(String, boolean)
Logging Before anyMethodCall jp.getArgs=[org.apache.tuscany.sca.node.SCANodeFactory, true]

These aspects provide static point cuts and advice. That is, the various methods, constructors, and exception points are constrained by the source code of the aspects. You can change these items via editing LoggingAspect or SimpleTracingAspect and rerunning the application.

Timing

Timing of various calls is also available via the AOP logging and tracing facility in Tuscany. The apsect UserTimingAspect is provided to time certain point cuts. As shown above, this AOP timing feature can be used for timing metrics for competitive analysis of performance gauges. The output of the timing is shown here, as a Logger.info method is called and timed.

Running org.apache.tuscany.sca.aspectj.TracingTestCase
Timing Around timedSection jp=call(void java.util.logging.Logger.info(String))
Oct 21, 2008 9:26:36 AM org.apache.tuscany.sca.aspectj.TracingTestCase info_aroundBody0
Timing Around timedSection Roundtrip is 32ms for jp.getSignature=void java.util.logging.Logger.info(String)

Unlike LoggingAspect and SimpleTracingAspect, the pointcut for UserTimingAspect is settable at runtime via the aop.xml runtimg configuration file. Look for the UserTimingAspect name, and note the expression in the pointcut element. You may change the name of expression to any valid AspectJ pointcut expression. Here calls to any Logger.info methods, regardless of arguments or return types are logged. For instance you may change this to "call( * calculator.CalculatorServiceImpl.multiply(..))" to time calls in your SCA application.

        <concrete-aspect name="org.apache.tuscany.sca.aspectj.UserTimingAspect"
           extends="org.apache.tuscany.sca.aspectj.TimingAspect"
           precedence="org.apache.tuscany.sca.aspectj.UserTimingAspect, *">
           <pointcut name="timedCall" 
              expression="call(* java.util.logging.Logger.info(..))"/>
        </concrete-aspect>

WebSphere Example

So far this article discussed logging and tracing for Tuscany applications. You can also turn on logging and tracing in various application servers that support Tuscany SCA applications.

Show WebSphere 7.0.0.1 plus SOA Feature Pack based on Tuscany output.

Apache Tomcat Example

Show Apache Tomcat J2EE application server plus Tuscany bundled SCA application.