Scripting Interfaces: NB Host Objects

PerfMetrics

• getNodes()
  Returns the various aggregation nodes in the system
• getLinks(String node)
  Returns the various links present in the brokering system as viewed by the aggregation node specified by the node parameter
• startMonitoring()
  Starts the monitoring by starting listening to published events
• stopMonitoring()
  Stops monitoring by un-subscribing to the topic.
• query(String xpathQuery)
  Queries the collected data sing XPath queries. XPath makes easier to express complex queries and base decisions on the collected statistics.

Examples:

	
	x = PerfMetrics.getNodes();
	y = PerfMetrics.getLinks(x[0]);
	
	badLink = PerfMetrics.query("//link[avgLatency > 5.0]/@id");
        jitter = PerfMetrics.query("//link[@id='" + badLink[0] + "']/jitter");
	

XML Structure:^{Subject to change}

	 <performanceData>
	 	<node id='...nodeid...'>
	 		<link id='...linkId...'>
			      <userGroup>A</userGroup>
     			      <avgLatency>3.5</avgLatency>
		              <jitter>0.4339609146118164</jitter>
			      <lossRate>0.0</lossRate>
			      <stdDev>1.9148542155126762</stdDev>
			</link>

   			<link ...
   			</link>
   			...
   		</node>
   		
   		<node ...
   		</node>
   		
   		...
	 </performanceData>
	

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