Problem with the configuration of the Ktor server for Kmongo (Kotlin Server + Mongo)

Question

I'm using Ktor with KMongo. I have a problem when I start the server in localhost and I make a simple 'get' request. The references aren't very clear and complete - https://litote.org/kmongo/ - regarding the configuration of the database on the server. Does anyone know how to solve the problem? I think it's a simple configuration problem, but I do not know how to solve it. I'm not using Spring.

This is the code for the connection to the KmongoDB :

package com.progettoetere.Routes

import io.ktor.application.
import io.ktor.response.respondText
import io.ktor.routing.*
import kotlinx.coroutines.runBlocking

import org.litote.kmongo.eq
import org.litote.kmongo.reactivestreams.*
import org.litote.kmongo.coroutine.*

fun Route.survey(){

    //ramo per i survey
    route("/survey"){

        //ritorno tutti i questionari
        get("/"){



                        val client = KMongo.createClient().coroutine //client whit Kotli coroutines
                        val database = client.getDatabase("test") //get a test database
                        val colSurvey = database.getCollection<Survey>() //get the collection of surveys

                        //start coroutine
                        runBlocking {

                            //get one survey for DEBUG with id == 1023
                            val dato: Survey? = colSurvey.findOne(Survey::id_survey eq 1023)

                            //check the survey
                            if (dato != null) {
                                call.respondText { "The survey is present" }
                            } else {
                                call.respondText { "The survey is not present" }
                            }
                        }

}

The error occurs when I create the client instance :

val client = KMongo.createClient().coroutine

This is the stack error :

2019-03-11 20:58:22.334 [main] INFO  Application - Responding at http://0.0.0.0:8080
2019-03-11 20:58:27.633 [nettyCallPool-4-1] INFO  org.mongodb.driver.cluster - Cluster created with settings {hosts=[localhost:27017], mode=SINGLE, requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms', maxWaitQueueSize=500}
2019-03-11 20:58:27.655 [nettyCallPool-4-1] DEBUG org.mongodb.driver.cluster - Updating cluster description to  {type=UNKNOWN, servers=[{address=localhost:27017, type=UNKNOWN, state=CONNECTING}]
2019-03-11 20:58:27.666 [cluster-ClusterId{value='5c86bde3cad88d4f128ae82c', description='null'}-localhost:27017] DEBUG org.mongodb.driver.connection - Closing connection connectionId{localValue:1}
2019-03-11 20:58:27.668 [cluster-ClusterId{value='5c86bde3cad88d4f128ae82c', description='null'}-localhost:27017] INFO  org.mongodb.driver.cluster - Exception in monitor thread while connecting to server localhost:27017
com.mongodb.MongoSocketOpenException: Exception opening socket
    at com.mongodb.internal.connection.AsynchronousSocketChannelStream$OpenCompletionHandler.failed(AsynchronousSocketChannelStream.java:117)
    at sun.nio.ch.Invoker.invokeUnchecked(Invoker.java:128)
    at sun.nio.ch.Invoker$2.run(Invoker.java:218)
    at sun.nio.ch.AsynchronousChannelGroupImpl$1.run(AsynchronousChannelGroupImpl.java:112)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.net.ConnectException: Connessione rifiutata
    at sun.nio.ch.UnixAsynchronousSocketChannelImpl.checkConnect(Native Method)
    at sun.nio.ch.UnixAsynchronousSocketChannelImpl.finishConnect(UnixAsynchronousSocketChannelImpl.java:252)
    at sun.nio.ch.UnixAsynchronousSocketChannelImpl.finish(UnixAsynchronousSocketChannelImpl.java:198)
    at sun.nio.ch.UnixAsynchronousSocketChannelImpl.onEvent(UnixAsynchronousSocketChannelImpl.java:213)
    at sun.nio.ch.EPollPort$EventHandlerTask.run(EPollPort.java:293)

Answer 1

Problem solved. I was convinced that the Mongo server started with the Ktor server, actually I had to manually start the Mongo server. Once the Mongo server was started from the terminal, the Ktor server was able to communicate with mongo during browser get or curl requests.