PostgreSQL database connection in Ktor part-1

PostgreSQL database connection in Ktor. 

 build.gradle dependency

// Exposed ORM library
implementation "org.jetbrains.exposed:exposed-core:0.35.1"
implementation "org.jetbrains.exposed:exposed-dao:0.35.1"
implementation "org.jetbrains.exposed:exposed-jdbc:0.35.1"implementation "org.postgresql:postgresql:42.2.2"
implementation 'com.zaxxer:HikariCP:3.4.2'

resource/hikari.properties

dataSourceClassName=org.postgresql.ds.PGSimpleDataSource
dataSource.user=postgres
dataSource.password=p123
dataSource.databaseName=db_ktor
dataSource.portNumber=5432
dataSource.serverName=localh

Database helper class

object DatabaseFactory {
    fun init() {
        // Database.connect(hikari())
        initDB()
        transaction {
            //create(Fruits, UserTable, ProductTable)
        }
    }

    private fun initDB() {
        // database connection is handled from hikari properties
        val config = HikariConfig("/hikari.properties")
        val ds = HikariDataSource(config)
        Database.connect(ds)
    }

    // database connection for h2 d
    private fun hikari(): HikariDataSource {
        val config = HikariConfig()
        config.driverClassName = "org.h2.Driver"
        config.jdbcUrl = "jdbc:h2:file:~/documents/db/h2db"
        config.maximumPoolSize = 3
        config.isAutoCommit = false
        config.transactionIsolation = "TRANSACTION_REPEATABLE_READ"
        config.validate()
        return HikariDataSource(config)
    }
}

Application class

fun main() {
    //val environment = System.getenv("KTOR_ENVIRONMENT") ?: "development"
    val configName = "application.conf"
    val appEngineEnv = applicationEngineEnvironment {
        config = HoconApplicationConfig(ConfigFactory.load(configName))
        log = LoggerFactory.getLogger("ktor.application")
        module {
            DatabaseFactory.init()
        }
        connector {
            host = config.property("ktor.deployment.host").getString()
            port = config.property("ktor.deployment.port").getString().toInt()
        }
    }

    embeddedServer(Netty, appEngineEnv).start(wait = true)
}