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Receiving Prometheus Metrics

Purpose:

This application demonstrates how to retrieve Prometheus metrics that are exported at an HTTP endpoint via the prometheus source.

Prerequisites:

The following steps must be executed to enable WSO2 Integrator: SI to publish and retrieve events via Prometheus.

  1. To complete the installation of the Prometheus extension in WSO2 Integrator: SI Tooling, follow the steps below:

    1. Download the following JARs.

    2. Place the JARs you downloaded in the <SI_HOME>/lib directory.

  3. Save the sample EnergyAlertApp Siddhi application.

  4. Download https://github.com/wso2/product-streaming-integrator-tooling/tree/421d942019a349151c763a2571f1f10f8c17f280/modules/samples/sample-clients/prometheus-client and issue the ant command as follows.

    ant

Executing the Sample:

  1. Start the EnergyAlertApp Siddhi application you saved by opening it and then clicking the Start button in the toolbar.

    When the Siddhi application is successfully started, the following messages are logged in the terminal.

    • ReceivePrometheusMetrics.siddhi - Started Successfully!
    • PowerConsumptionStream has successfully connected at http://localhost:9080

Viewing the Results:

Messages similar to the following are logged in the terminal. 

- INFO {io.siddhi.core.stream.output.sink.LogSink} - HIGH POWER CONSUMPTION : Event{timestamp=1*********, data=[server001, F3Room2, **, **], isExpired=false}
- INFO {io.siddhi.core.stream.output.sink.LogSink} - HIGH POWER CONSUMPTION : Event{timestamp=1*********, data=[server002, F2Room2, **, **], isExpired=false}

The complete sample Siddhi Application is as follows.

@App:name("EnergyAlertApp")
@App:description("Use siddhi-io-prometheus retrieve and analyse Prometheus metrics in Siddhi")


@source(type='prometheus' , target.url='http://localhost:9080/metrics',metric.type='counter', metric.name='total_device_power_consumption_WATTS', scrape.interval='5',
@map(type='keyvalue'))
define stream devicePowerStream(deviceID string, roomID string, value int);

@sink(type='log', priority='WARN', prefix ='High power consumption')
define stream AlertStream (deviceID string, roomID string, initialPower int, finalPower int);

@sink(type='log', priority='WARN', prefix ='Logging purpose')
define stream LogStream (deviceID string, roomID string, power int);

@info(name='power increase pattern')
from every( e1=devicePowerStream ) -> e2=devicePowerStream[ e1.deviceID == deviceID and (e1.value + 5) <= value]
    within 1 min
select e1.deviceID, e1.roomID, e1.value as initialPower, e2.value as finalPower
insert into AlertStream;