A performance monitor for Storm topologies. Consists of:

1. A TaskHook that extracts topology information and manages local metrics

2. A simple HTTP server that can report the last 100 seconds of gathered metrics

3. A set of configurable charts that understand the metrics schema and which can help identify performance problems in the monitored topology:

• A histogram that shows pending tuple counts (e.g. the backlog) on each stream in the topology
• A "Share of Voice" chart that shows the pending tuple counts for a given stream for each of a component's tasks
• A "Share of Voice" chart that shows the relative size of the backlogs on all streams for the topology

So for this you might see this

HashMap map = new HashMap();
map.put("storm.monitor.host", a_String_IP_address);
map.put("storm.monitor.port", an_Integer_Port_Number);
map.put("storm.monitor.start", System.currentTimeMillis());  // should be the same for all calls
map.put("storm.monitor.bucketsize", 1000L);

MonitorClient mclient = MonitorClient.forConfig(conf);

   ...

//  There are multiple metric groups, each with multiple metrics.
//  Components have names and multiple instances, each of which has an integer ID
   
mclient.declare(metricGroup,metric,task_id,component_id);

   ...   
   
mclient.increment(metricGroup,metric, 1L , task_id);

You can also add the MonitorClient to all spouts and bolts in a topology with this bit of code in the driver class before submitting the cluster:

TaskHook.registerTo(config);

where variable config is of type backtype.storm.Config and contains the properties described above.

See web/monitor-web in this repo for sample HTML and the Javascript it requires.