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/*
* This file is part of LibEuFin.
* Copyright (C) 2020 Taler Systems S.A.
*
* LibEuFin is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation; either version 3, or
* (at your option) any later version.
*
* LibEuFin is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General
* Public License for more details.
*
* You should have received a copy of the GNU Affero General Public
* License along with LibEuFin; see the file COPYING. If not, see
* <http://www.gnu.org/licenses/>
*/
package tech.libeufin.nexus
import com.cronutils.model.definition.CronDefinitionBuilder
import com.cronutils.model.time.ExecutionTime
import com.cronutils.parser.CronParser
import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
import io.ktor.client.HttpClient
import kotlinx.coroutines.*
import kotlinx.coroutines.time.delay
import org.jetbrains.exposed.sql.transactions.transaction
import tech.libeufin.nexus.bankaccount.fetchBankAccountTransactions
import tech.libeufin.nexus.bankaccount.submitAllPaymentInitiations
import tech.libeufin.nexus.server.FetchSpecJson
import java.lang.IllegalArgumentException
import java.time.Duration
import java.time.Instant
import java.time.ZonedDateTime
import kotlin.system.exitProcess
private data class TaskSchedule(
val taskId: Long,
val name: String,
val type: String,
val resourceType: String,
val resourceId: String,
val params: String
)
private suspend fun runTask(client: HttpClient, sched: TaskSchedule) {
logger.info("running task $sched")
try {
when (sched.resourceType) {
"bank-account" -> {
when (sched.type) {
// Downloads and ingests the payment records from the bank.
"fetch" -> {
val fetchSpec = jacksonObjectMapper().readValue(sched.params, FetchSpecJson::class.java)
fetchBankAccountTransactions(client, fetchSpec, sched.resourceId)
/**
* NOTE: the previous operation COULD have had problems but that
* is tolerated because the communication with the backend CAN be
* unreliable. As of logging: not doing it here twice, since every
* error should already have been logged when it originated.
*/
}
// Submits the payment preparations that are found in the database.
"submit" -> {
submitAllPaymentInitiations(client, sched.resourceId)
}
else -> {
logger.error("task type ${sched.type} not supported")
}
}
}
else -> logger.error("task on resource ${sched.resourceType} not supported")
}
}
catch (e: Exception) {
logger.error("Exception during task $sched: ${e.message})")
/**
* Not exiting the process since the error can be temporary:
* name resolution problem, Nexus connectivity problem, ...
*/
}
catch (so: StackOverflowError) {
logger.error(so.stackTraceToString())
exitProcess(1)
}
}
object NexusCron {
val parser = run {
val cronDefinition =
CronDefinitionBuilder.defineCron()
.withSeconds().and()
.withMinutes().and()
.withHours().and()
.withDayOfMonth().optional().and()
.withMonth().optional().and()
.withDayOfWeek().optional()
.and().instance()
CronParser(cronDefinition)
}
}
// Fails whenever an unmanaged Throwable reaches the root coroutine.
val fallback = CoroutineExceptionHandler { _, err ->
logger.error(err.stackTraceToString())
exitProcess(1)
}
// Internal routine ultimately scheduling the tasks.
private suspend fun operationScheduler(httpClient: HttpClient) {
// First, assign next execution time stamps to all tasks that need them
transaction {
NexusScheduledTaskEntity.find {
NexusScheduledTasksTable.nextScheduledExecutionSec.isNull()
}.forEach {
val cron = try { NexusCron.parser.parse(it.taskCronspec) }
catch (e: IllegalArgumentException) {
logger.error("invalid cronspec in schedule ${it.resourceType}/${it.resourceId}/${it.taskName}")
return@forEach
}
val zonedNow = ZonedDateTime.now()
val parsedCron = ExecutionTime.forCron(cron)
val next = parsedCron.nextExecution(zonedNow)
logger.info("Scheduling task ${it.taskName} at $next (now is $zonedNow).")
it.nextScheduledExecutionSec = next.get().toEpochSecond()
}
}
val nowSec = Instant.now().epochSecond
// Second, find tasks that are due
val dueTasks = transaction {
NexusScheduledTaskEntity.find {
NexusScheduledTasksTable.nextScheduledExecutionSec lessEq nowSec
}.map {
TaskSchedule(it.id.value, it.taskName, it.taskType, it.resourceType, it.resourceId, it.taskParams)
}
} // Execute those due tasks and reset to null the next execution time.
dueTasks.forEach {
runTask(httpClient, it)
transaction {
val t = NexusScheduledTaskEntity.findById(it.taskId)
if (t != null) {
// Reset next scheduled execution
t.nextScheduledExecutionSec = null
t.prevScheduledExecutionSec = nowSec
}
}
}
}
// Alternative scheduler based on Java Timer, but same perf. as the while-true one.
/*
private val javaTimer = Timer()
suspend fun javaTimerOperationScheduler(httpClient: HttpClient) {
operationScheduler(httpClient)
javaTimer.schedule(
delay = 1000L,
action = { runBlocking { javaTimerOperationScheduler(httpClient) } }
)
}
*/
suspend fun whileTrueOperationScheduler(httpClient: HttpClient) {
while (true) {
operationScheduler(httpClient)
// Wait the shortest period that the cron spec would allow.
delay(Duration.ofSeconds(1))
}
}
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