KafkaTopology.kt

/*
 * Table Data Import Service
 * Copyright (C) 2020 Memoriav
 *
 * This program 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 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package org.memobase

import com.beust.klaxon.Klaxon
import org.apache.kafka.streams.KeyValue
import org.apache.kafka.streams.StreamsBuilder
import org.apache.kafka.streams.kstream.KStream
import org.memobase.models.*
import org.memobase.settings.SettingsLoader

class KafkaTopology(private val settings: SettingsLoader) {
    private val parser = TableParser(settings)

    private val reportingTopic = settings.outputTopic + "-reporting"

    private val klaxon = Klaxon()
    private val acceptedFormats = listOf(Formats.csv, Formats.xlsx, Formats.tsv, Formats.xls, Formats.ods)

    fun prepare(): StreamsBuilder {
        val builder = StreamsBuilder()

        val parsedTable = builder
            .stream<String, String>(settings.inputTopic)
            .mapValues { value -> klaxon.parse<Message>(value) }
            .filter { _, value -> acceptedFormats.contains(value?.format) }
            .mapValues { key, value -> parser.parseTable(key, value!!) }




        return builder
    }

    private fun processValidInput(stream: KStream<String, ParserResult>) {
        val records = stream
            .flatMapValues { _, value -> value.messages }

        records
            .map { _, value -> KeyValue(value.key, value.value) }
            .filter { _, value -> value.isNotEmpty() }
            .mapValues { value -> value.toJsonString() }
            .to(settings.outputTopic)

        records
            .map { _, value -> KeyValue(value.report.id, value.report) }
            .mapValues { value -> value.toJson() }
            .to(reportingTopic)

        stream
            .map { _, value -> KeyValue(value.processReport.id, value.processReport.toJson()) }
            .to(settings.processReportTopic)
    }
}