I’m trying to do the connection pooling and caching tutorial under Ktor doc:
connection pooling and caching tutorial

I keep getting this error:

Exception in thread "main" io.ktor.server.config.ApplicationConfigurationException: Property storage.driverClassName not found.
at io.ktor.server.config.HoconApplicationConfig.property(HoconApplicationConfig.kt:47)
at io.ktor.server.config.MergedApplicationConfig.property(MergedApplicationConfig.kt:47)
at io.ktor.server.config.MergedApplicationConfig.property(MergedApplicationConfig.kt:47)
at com.samordonez.dao.DatabaseSingleton.init(DatabaseSingleton.kt:14)
at com.samordonez.ApplicationKt.module(Application.kt:11)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at kotlin.reflect.jvm.internal.calls.CallerImpl$Method.callMethod(CallerImpl.kt:97)
at kotlin.reflect.jvm.internal.calls.CallerImpl$Method$Static.call(CallerImpl.kt:106)
at kotlin.reflect.jvm.internal.KCallableImpl.callDefaultMethod$kotlin_reflection(KCallableImpl.kt:188)
at kotlin.reflect.jvm.internal.KCallableImpl.callBy(KCallableImpl.kt:111)
at io.ktor.server.engine.internal.CallableUtilsKt.callFunctionWithInjection(CallableUtils.kt:119)
at io.ktor.server.engine.internal.CallableUtilsKt.executeModuleFunction(CallableUtils.kt:36)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading$launchModuleByName$1.invoke(ApplicationEngineEnvironmentReloading.kt:332)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading$launchModuleByName$1.invoke(ApplicationEngineEnvironmentReloading.kt:331)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.avoidingDoubleStartupFor(ApplicationEngineEnvironmentReloading.kt:356)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.launchModuleByName(ApplicationEngineEnvironmentReloading.kt:331)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.access$launchModuleByName(ApplicationEngineEnvironmentReloading.kt:32)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading$instantiateAndConfigureApplication$1.invoke(ApplicationEngineEnvironmentReloading.kt:312)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading$instantiateAndConfigureApplication$1.invoke(ApplicationEngineEnvironmentReloading.kt:310)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.avoidingDoubleStartup(ApplicationEngineEnvironmentReloading.kt:338)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.instantiateAndConfigureApplication(ApplicationEngineEnvironmentReloading.kt:310)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.createApplication(ApplicationEngineEnvironmentReloading.kt:150)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.start(ApplicationEngineEnvironmentReloading.kt:277)
at io.ktor.server.netty.NettyApplicationEngine.start(NettyApplicationEngine.kt:216)
at io.ktor.server.netty.EngineMain.main(EngineMain.kt:23)
at com.samordonez.ApplicationKt.main(Application.kt:8)

Here’s my DatabaseSingleton.kt

package com.samordonez.dao

import com.samordonez.models.*
import com.zaxxer.hikari.*
import io.ktor.server.config.*
import kotlinx.coroutines.*
import org.jetbrains.exposed.sql.*
import org.jetbrains.exposed.sql.transactions.*
import org.jetbrains.exposed.sql.transactions.experimental.*
import java.io.*

object DatabaseSingleton {
    fun init(config: ApplicationConfig) {
        val driverClassName = config.property("storage.driverClassName").getString()
        val jdbcURL = config.property("storage.jdbcURL").getString() +
            (config.propertyOrNull("storage.dbFilePath")?.getString()?.let {
                File(it).canonicalFile.absolutePath
            } ?: "")

    val database = Database.connect(createHikariDataSource(url = jdbcURL, driver = driverClassName))
    transaction(database) {
        SchemaUtils.create(Articles)
    }
}

    private fun createHikariDataSource(
        url: String,
        driver: String
    ) = HikariDataSource(HikariConfig().apply {
        driverClassName = driver
        jdbcUrl = url
        maximumPoolSize = 3
        isAutoCommit = false
        transactionIsolation = "TRANSACTION_REPEATABLE_READ"
        validate()
    })

    suspend fun <T> dbQuery(block: suspend () -> T): T =
        newSuspendedTransaction(Dispatchers.IO) { block() }

}

And here’s my application.conf file

ktor {
deployment {
    port = 8080
    port = ${?PORT}
}
application {
    modules = [ com.samordonez.ApplicationKt.module ]
}
storage {
    driverClassName = "org.h2.Driver"
    jdbcURL = "jdbc:h2:file:"
    dbFilePath = build/db
    ehcacheFilePath = build/ehcache
}
}

1. What am I missing here?

2. It’s saying driverClassName is missing but, I think, it was already handled under my application.conf