The example located in the samples/sla/monitor folder demonstrates an approach to provide "Service Level Agreement" monitoring. This example makes uses of the example Switchyard application located in the samples/ordermgmt folder. This example will shows:

This example shows a simple Service Level Agreement that checks whether a service response time exceeds expected levels. The CEP rule detects whether a situation of interest has occurred, and if so, creates aorg.overlord.rtgov.analytics.situation.Situation object and initializes it with the appropriate description or severity information, before forwarding it back into the EPN. This results in the "Situation" object being published as a notification on the "Situations" subject.

The CEP rule is:

import org.overlord.rtgov.analytics.service.ResponseTime
import org.overlord.rtgov.analytics.situation.Situation

global org.overlord.rtgov.ep.EPContext epc

declare ResponseTime
    @role( event )
end

rule "check for SLA violations"
when
    $rt : ResponseTime() from entry-point "ServiceResponseTimes"
then

        if ($rt.getAverage() > 200) {
                epc.logError("\r\n\r\n**** RESPONSE TIME "+$rt.getAverage()+"ms EXCEEDED SLA FOR "+$rt.getServiceType()+" ****\r\n");

                Situation situation=new Situation();

                situation.setType("SLA Violation");
                situation.setSubject(Situation.createSubject($rt.getServiceType(), $rt.getOperation(),
                                                $rt.getFault()));
                situation.setTimestamp(System.currentTimeMillis());

                situation.getProperties().putAll($rt.getProperties());

                if ($rt.getRequestId() != null) {
                        situation.getActivityTypeIds().add($rt.getRequestId());
                }
                if ($rt.getResponseId() != null) {
                        situation.getActivityTypeIds().add($rt.getResponseId());
                }

                situation.getContext().addAll($rt.getContext());

                String serviceName=$rt.getServiceType();

                if (serviceName.startsWith("{")) {
                        serviceName = javax.xml.namespace.QName.valueOf(serviceName).getLocalPart();
                }

                if ($rt.getAverage() > 400) {
                        situation.setDescription(serviceName+" exceeded maximum response time of 400 ms");
                        situation.setSeverity(Situation.Severity.Critical);
                } else if ($rt.getAverage() > 320) {
                        situation.setDescription(serviceName+" exceeded response time of 320 ms");
                        situation.setSeverity(Situation.Severity.High);
                } else if ($rt.getAverage() > 260) {
                        situation.setDescription(serviceName+" exceeded response time of 260 ms");
                        situation.setSeverity(Situation.Severity.Medium);
                } else {
                        situation.setDescription(serviceName+" exceeded response time of 200 ms");
                        situation.setSeverity(Situation.Severity.Low);
                }

                epc.handle(situation);
        }

end

The "out of the box" active collection configuration is pre-initialized with a collection for the org.overlord.rtgov.analytics.situation.Situation objects, subscribing to the "Situations" subject from the Event Processor Network. Therefore any detected SLA violations will automatically be stored in this collection (accessible via a RESTful service), and reported to the associated JMX notifier.

{
    "collection" : "Situations"
}

@Path("/monitor")
@ApplicationScoped
public class SLAMonitor {

    private static final String SERVICE_RESPONSE_TIMES = "ServiceResponseTimes";
    private static final String SITUATIONS = "Situations";

    private static final Logger LOG=Logger.getLogger(SLAMonitor.class.getName());

    private ActiveCollectionManager _acmManager=null;

    private ActiveList _serviceResponseTime=null;
    private ActiveList _situations=null;

    /**
     * This is the default constructor.
     */
    public SLAMonitor() {

        try {
            _acmManager = ActiveCollectionManagerAccessor.getActiveCollectionManager();

            _serviceResponseTime = (ActiveList)
                    _acmManager.getActiveCollection(SERVICE_RESPONSE_TIMES);

            _situations = (ActiveList)
                    _acmManager.getActiveCollection(SITUATIONS);

        } catch (Exception e) {
            LOG.log(Level.SEVERE, "Failed to initialize active collection manager", e);
        }

    }

@GET
    @Path("/situations")
    @Produces("application/json")
    public java.util.List<Situation> getSituations() {
        java.util.List<Situation> ret=new java.util.ArrayList<Situation>();

        for (Object obj : _situations) {
            if (obj instanceof Situation) {
                ret.add((Situation)obj);
            }
        }

        return (ret);
    }

The example located in the samples/sla/report folder demonstrates how to provide pluggable reports that can access information in the activity store. This example uses the activity information to compile a Service Level Agreement report, highlighting violations above a specified response time.

This example shows:

This example provides a simple Service Level Agreement report, based on identifying service invocations that exceed a specified maximum response time over an optionally specified averaged duration. If the averaged duration is not specified, then each service invocation is checked to determine if it exceeded the maximum response time. If so, it gets added to the report. If the averaged duration is specified, then when an invocation is detected (that exceeds the max response time), then all other suitable invocations within the specified duration are averaged to determine if the response time overall still exceeds the specified maximum. This is to ensure that periodic spikes are not unnecessarily reported.

It is also possible to optionally specify a business calendar, which can be used to determine the business period in which activities are of interest. If SLA violations occur outside the specified business calendar, then they are not relevant.

The report definition is:

[
  {
    "name" : "SLAReport",
    "generator" : {
      "@class" : "org.overlord.rtgov.reports.MVELReportGenerator",
       "scriptLocation" : "SLAReport.mvel"
    }
  }
]

You can find the MVEL based report generator script in the ${rtgov}/samples/sla/report/src/main/resources folder.

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
   <soap:Body>
      <orders:submitOrder xmlns:orders="urn:switchyard-quickstart-demo:orders:1.0">
         <order>
            <orderId>1</orderId>
            <itemId>BUTTER</itemId>
            <quantity>100</quantity>
            <customer>Fred</customer>
         </order>
      </orders:submitOrder>
   </soap:Body>
</soap:Envelope>

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
   <soap:Body>
      <orders:submitOrder xmlns:orders="urn:switchyard-quickstart-demo:orders:1.0">
         <order>
            <orderId>3</orderId>
            <itemId>JAM</itemId>
            <quantity>100</quantity>
            <customer>Fred</customer>
         </order>
      </orders:submitOrder>
   </soap:Body>
</soap:Envelope>

mvn exec:java -Dreq=order1
mvn exec:java -Dreq=order3

http://localhost:8080overlordrtgovreportgeneratereport=SLAReport&startDay=1&startMonth=1&startYear=2013&endDay=31&endMonth=12&endYear=2013&maxResponseTime=400&averagedDuration=450

&calendar=Default