pl.allegro.tech.servicemesh.envoycontrol.consul.services.ConsulServiceMapper.kt Maven / Gradle / Ivy

Go to download
package pl.allegro.tech.servicemesh.envoycontrol.consul.services

import pl.allegro.tech.servicemesh.envoycontrol.logger
import pl.allegro.tech.servicemesh.envoycontrol.services.ServiceInstance
import kotlin.text.Regex.Companion.escape

typealias ConsulServiceInstance = pl.allegro.tech.discovery.consul.recipes.watch.catalog.ServiceInstance

open class ConsulServiceMapper(
    private val canaryTag: String = "", weightTag: String = "", private val defaultWeight: Int = 1
) {
    private val logger by logger()

    private val weightEnabled = weightTag.isNotEmpty()
    private val weightTagRegex: Regex = weightTag.let { """${escape(it)}:(\d+)""".toRegex() }

    open fun toDomainInstance(consulInstance: ConsulServiceInstance): ServiceInstance {
        val canary = isCanary(consulInstance)
        val actualWeight = getActualWeight(consulInstance)
        return ServiceInstance(
            id = consulInstance.serviceId,
            tags = consulInstance.serviceTags.toSet(),
            address = consulInstance.serviceAddress.get(),
            port = consulInstance.servicePort.get(),
            regular = true, // override this class if in some case canary are not to be included in regular set
            canary = canary,
            weight = getWeight(actualWeight)
        )
    }

    protected fun isCanary(consulInstance: ConsulServiceInstance): Boolean = when {
        canaryTag.isEmpty() -> false
        else -> consulInstance.serviceTags.orEmpty().contains(canaryTag)
    }

    protected fun getWeight(actualWeight: Int): Int {
        return actualWeight.coerceAtLeast(1)
    }

    protected fun getActualWeight(consulInstance: ConsulServiceInstance): Int {
        if (!weightEnabled) {
            return defaultWeight
        }
        return consulInstance.serviceTags.orEmpty().mapNotNull { weightTagRegex.matchEntire(it) }
            .map { it.groupValues[1] }.mapNotNull { it.runCatching { toInt() }.getOrNull() }.let {
                when (it.size) {
                    0 -> defaultWeight
                    else -> {
                        if (it.size > 1) {
                            logger.warn(
                                "Multiple weight tags on consul instance ${consulInstance.serviceId}. Expected 0 or 1."
                            )
                        }
                        it[0]
                    }
                }
            }
    }
}