repositories {
    mavenCentral()
}

dependencies {
    implementation("dev.evo.prometheus", "prometheus-kt-ktor", "0.2.3")
}

import dev.evo.prometheus.LabelSet
import dev.evo.prometheus.PrometheusMetrics
import dev.evo.prometheus.jvm.DefaultJvmMetrics

class ProcessingLabels : LabelSet() {
    var source by label()
}

object AppMetrics : PrometheusMetrics() {
    val processedProducts by histogram("processed_products", logScale(0, 2)) {
        ProcessingLabels()
    }
    val jvm by submetrics(DefaultJvmMetrics())
}

import kotlinx.coroutines.delay

suspend fun startProcessing() {
    while (true) {
        AppMetrics.processedProducts.measureTime({
            source = "manual"
        }) {
            // Processing
            delay(100)
        }
    }
}

import dev.evo.prometheus.ktor.metricsModule

import io.ktor.server.engine.embeddedServer
import io.ktor.server.netty.Netty

suspend fun main(args: Array<String>) {
    val metricsApp = embeddedServer(
        Netty,
        port = 9090,
        module = {
            metricsModule(AppMetrics)
        }
    )
            .start(wait = false)
    
    // Start processing
    startProcessing()
    
    metricsApp.stop(1000, 2000)
}