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I tried to integrate kamon-prometheus with akka stream project but at http://localhost:9095/ it loads an empty page.In the console I could see the message that metrics information is available at http://localhost:9095/. When I tried with akka quickstart project, it worked fine.

Is kamon supported for akka streams?

user51
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iamsal
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2 Answers2

7

Kamon uses aspecj heavily to gather some of the metrics. Please make sure that java agent aspectj-weaver is added to the boot of you JVM. See different options in this documentation.

You also need to add dependencies to build.sbt

libraryDependencies += "io.kamon" %% "kamon-core" % "1.1.0"
libraryDependencies += "io.kamon" %% "kamon-prometheus" % "1.0.0"

Disable built-in server in kamon-prometheus by changing this setting key in application.conf file.

kamon.prometheus.start-embedded-http-server = no

Add PrometheusReporter to Kamon

    import kamon.Kamon
    import kamon.prometheus.PrometheusReporter
    
    private val reporter = new PrometheusReporter()
    private val registry = Kamon.addReporter(reporter)

And serve results of metrics with akka-http by defining a route and getting data from reporter.scrapeData().

     val metrics = path("metrics") {
      encodeResponse {
        val prometheusContentType: ContentType.NonBinary = {
          ContentType.parse("text/plain; version=0.0.4; charset=utf-8").right.get.asInstanceOf[ContentType.NonBinary]
        }
        Kamon.gauge("metrics_called").increment()
        complete(
          HttpResponse(
            status = StatusCodes.OK,
            entity = HttpEntity(prometheusContentType, reporter.scrapeData())
          )
        )
      }
    }

Or serve metrics to any incoming http request with code

    akka.http.scaladsl
      .Http(actorSystem)
      .bindAndHandleSync(
        _ => {
          Kamon.gauge("metrics_called").increment()
          HttpResponse(
            status = StatusCodes.OK,
            entity = HttpEntity(prometheusContentType, reporter.scrapeData())
          )
        },
        "0.0.0.0",
        9015
      )

In case if you receive blank page, make sure that Kamon gathers some metrics in the system. You could test this by adding Kamon.gauge("metrics_called").increment() into a http route for example.

Ivan Stanislavciuc
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  • Still it loads an empty page. – iamsal Jan 09 '19 at 10:05
  • I tried that by adding Kamon.counter("app.orders.sent").increment() and I was able to see this with kamon-prometheus embedded server. – iamsal Jan 09 '19 at 12:42
  • I have already added the below lines in plugins.sbt. resolvers += Resolver.bintrayRepo("kamon-io", "sbt-plugins") addSbtPlugin("io.kamon" % "sbt-aspectj-runner" % "1.1.0") – iamsal Jan 09 '19 at 13:20
  • That was a really helpful point.I was doing run main all the time.And on doing sbt run , I think it will work.Now I am seeing some error in console. – iamsal Jan 09 '19 at 15:19
  • No.I am using these libraries . `"io.kamon" %% "kamon-core" % "1.0.0"` `"io.kamon" %% "kamon-logback" % "1.0.0"` `"io.kamon" %% "kamon-akka-2.5" % "1.0.1"` `"io.kamon" %% "kamon-prometheus" % "1.0.0"` – iamsal Jan 09 '19 at 15:21
3

I was trying to run Main from Intellij and that was the reason why I did not get the metrics.With the suggestion from @Ivan Stanislavciuc , I tried sbt run and it worked.

iamsal
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  • It would be nice to give me some credit by upvoting my answer at least – Ivan Stanislavciuc Jan 15 '19 at 08:30
  • @IvanStanislavciuc Due to reputation being less than 15, I am not allowed to upvote :( .Sorry ,but I tried it and it says "Thanks for the feedback! Votes cast by those with less than 15 reputation are recorded, but do not change the publicly displayed post score." – iamsal Jan 15 '19 at 13:54