observability-setup

Observability Setup Skill

This skill provides patterns for setting up observability in Nais applications.

Required Health Endpoints

import io.ktor.server.application.*
import io.ktor.server.response.*
import io.ktor.server.routing.*
import io.ktor.http.*

fun Application.configureHealthEndpoints(
    dataSource: HikariDataSource,
    kafkaProducer: KafkaProducer<String, String>
) {
    routing {
        get("/isalive") {
            call.respondText("Alive", ContentType.Text.Plain)
        }

        get("/isready") {
            val databaseHealthy = checkDatabase(dataSource)
            val kafkaHealthy = checkKafka(kafkaProducer)

            if (databaseHealthy && kafkaHealthy) {
                call.respondText("Ready", ContentType.Text.Plain)
            } else {
                call.respondText(
                    "Not ready",
                    ContentType.Text.Plain,
                    HttpStatusCode.ServiceUnavailable
                )
            }
        }
    }
}

fun checkDatabase(dataSource: HikariDataSource): Boolean {
    return try {
        dataSource.connection.use { it.isValid(1) }
    } catch (e: Exception) {
        false
    }
}

fun checkKafka(producer: KafkaProducer<String, String>): Boolean {
    return try {
        producer.partitionsFor("health-check-topic").isNotEmpty()
    } catch (e: Exception) {
        false
    }
}

Prometheus Metrics Setup

import io.micrometer.core.instrument.Clock
import io.micrometer.core.instrument.binder.jvm.*
import io.micrometer.prometheus.PrometheusConfig
import io.micrometer.prometheus.PrometheusMeterRegistry
import io.prometheus.client.CollectorRegistry
import io.ktor.server.metrics.micrometer.*
import io.ktor.server.response.*
import io.ktor.http.*

val meterRegistry = PrometheusMeterRegistry(
    PrometheusConfig.DEFAULT,
    CollectorRegistry.defaultRegistry,
    Clock.SYSTEM
)

fun Application.configureMetrics() {
    install(MicrometerMetrics) {
        registry = meterRegistry
        // Production pattern from navikt/ao-oppfolgingskontor
        meterBinders = listOf(
            JvmMemoryMetrics(),        // Heap, non-heap memory
            JvmGcMetrics(),            // Garbage collection
            ProcessorMetrics(),        // CPU usage
            UptimeMetrics()            // Application uptime
        )
    }

    routing {
        get("/metrics") {
            call.respondText(
                meterRegistry.scrape(),
                ContentType.parse("text/plain; version=0.0.4")
            )
        }
    }
}