Device Service SDK - Go Services Metrics

Built-In

The following built-in device service metrics are collected by the Device SDK

1. EventSent - Number of Events that have been sent from the Device Service
2. ReadingsSent - Number of Reading that have been sent from the Device Service
3. Common Metrics - Set of service metrics common to all EdgeX Services. See Common Service Metrics for list of all these metrics.

See Device Service Configuration Properties for detail on configuring device service metrics

Custom

The Custom Device Service Metrics capability allows for device service developers to define, collect and report their own service metrics beyond the common built-in service metrics supplied by the Device SDK.

The following are the steps to collect and report service metrics:

1. Determine the metric type that needs to be collected

   • counter - Track the integer count of something
   • gauge - Track the integer value of something
   • gaugeFloat64 - Track the float64 value of something
   • timer - Track the time it takes to accomplish a task
   • histogram - Track the integer value variance of something

2. Create instance of the metric type from github.com/rcrowley/go-metrics

   • myCounter = gometrics.NewCounter()
   • myGauge = gometrics.NewGauge()
   • myGaugeFloat64 = gometrics.NewGaugeFloat64()
   • myTimer = gometrics.NewTime()
   • myHistogram = gometrics.NewHistogram(gometrics.NewUniformSample(<reservoir size))

3. Determine if there are any tags to report along with your metric. Not common so nil is typically passed for the tags map[strings]string parameter in the next step.

4. Register your metric(s) with the MetricsManager from the sdkreference. See Device SDK API for more details:

5. service.MetricsManager().Register("MyCounterName", myCounter, nil)

6. Collect the metric

   • myCounter.Inc(someIntvalue)
   • myCounter.Dec(someIntvalue)
   • myGauge.Update(someIntvalue)
   • myGaugeFloat64.Update(someFloatvalue)
   • myTimer.Update(someDuration)
   • myTimer.Time(func { do sometime})
   • myTimer.UpdateSince(someTimeValue)
   • myHistogram.Update(someIntvalue)

7. Configure reporting of the service's metrics. See Writable.Telemetry configuration details in the Common Configuration section for more detail.

Writable:
  Telemetry
    Interval: "30s"
    Metrics: # All service's metric names must be present in this list.
      MyCounterName: true
      MyGaugeName: true
      MyGaugeFloat64Name: true
      MyTimerName: true
      MyHistogram: true
   Tags: # Contains the service level tags to be attached to all the service's metrics
     Gateway: "my-iot-gateway" # Tag must be added here or via Consul Env Override can only change existing value, not added new ones.