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/*
* Copyright 2017 data Artisans GmbH
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.dataartisans.flinktraining.solutions.datastream_scala.process
import com.dataartisans.flinktraining.exercises.datastream_java.datatypes.{TaxiFare, TaxiRide}
import com.dataartisans.flinktraining.exercises.datastream_java.sources.{CheckpointedTaxiFareSource, CheckpointedTaxiRideSource}
import com.dataartisans.flinktraining.exercises.datastream_java.utils.ExerciseBase
import com.dataartisans.flinktraining.exercises.datastream_java.utils.ExerciseBase._
import org.apache.flink.api.common.state.{ValueState, ValueStateDescriptor}
import org.apache.flink.api.java.utils.ParameterTool
import org.apache.flink.streaming.api.TimeCharacteristic
import org.apache.flink.streaming.api.functions.co.CoProcessFunction
import org.apache.flink.streaming.api.scala.{StreamExecutionEnvironment, _}
import org.apache.flink.util.Collector
/**
* Scala reference implementation for the "Expiring State" exercise of the Flink training
* (http://training.data-artisans.com).
*
* The goal for this exercise is to enrich TaxiRides with fare information.
*
* Parameters:
* -rides path-to-input-file
* -fares path-to-input-file
*
*/
object ExpiringStateSolution {
val unmatchedRides = new OutputTag[TaxiRide]("unmatchedRides") {}
val unmatchedFares = new OutputTag[TaxiFare]("unmatchedFares") {}
def main(args: Array[String]) {
// parse parameters
val params = ParameterTool.fromArgs(args)
val ridesFile = params.get("rides", ExerciseBase.pathToRideData)
val faresFile = params.get("fares", ExerciseBase.pathToFareData)
val servingSpeedFactor = 600 // 10 minutes worth of events are served every second
// set up streaming execution environment
val env = StreamExecutionEnvironment.getExecutionEnvironment
env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime)
env.setParallelism(ExerciseBase.parallelism)
val rides = env
.addSource(rideSourceOrTest(new CheckpointedTaxiRideSource(ridesFile, servingSpeedFactor)))
.filter { ride => ride.isStart && (ride.rideId % 1000 != 0) }
.keyBy("rideId")
val fares = env
.addSource(fareSourceOrTest(new CheckpointedTaxiFareSource(faresFile, servingSpeedFactor)))
.keyBy("rideId")
val processed = rides.connect(fares).process(new EnrichmentFunction)
printOrTest(processed.getSideOutput[TaxiFare](unmatchedFares))
env.execute("ExpiringState (scala)")
}
class EnrichmentFunction extends CoProcessFunction[TaxiRide, TaxiFare, (TaxiRide, TaxiFare)] {
// keyed, managed state
lazy val rideState: ValueState[TaxiRide] = getRuntimeContext.getState(
new ValueStateDescriptor[TaxiRide]("saved ride", classOf[TaxiRide]))
lazy val fareState: ValueState[TaxiFare] = getRuntimeContext.getState(
new ValueStateDescriptor[TaxiFare]("saved fare", classOf[TaxiFare]))
override def processElement1(ride: TaxiRide,
context: CoProcessFunction[TaxiRide, TaxiFare, (TaxiRide, TaxiFare)]#Context,
out: Collector[(TaxiRide, TaxiFare)]): Unit = {
val fare = fareState.value
if (fare != null) {
fareState.clear()
out.collect((ride, fare))
}
else {
rideState.update(ride)
// as soon as the watermark arrives, we can stop waiting for the corresponding fare
context.timerService.registerEventTimeTimer(ride.getEventTime)
}
}
override def processElement2(fare: TaxiFare,
context: CoProcessFunction[TaxiRide, TaxiFare, (TaxiRide, TaxiFare)]#Context,
out: Collector[(TaxiRide, TaxiFare)]): Unit = {
val ride = rideState.value
if (ride != null) {
rideState.clear()
out.collect((ride, fare))
}
else {
fareState.update(fare)
// as soon as the watermark arrives, we can stop waiting for the corresponding ride
context.timerService.registerEventTimeTimer(fare.getEventTime)
}
}
override def onTimer(timestamp: Long,
ctx: CoProcessFunction[TaxiRide, TaxiFare, (TaxiRide, TaxiFare)]#OnTimerContext,
out: Collector[(TaxiRide, TaxiFare)]): Unit = {
if (fareState.value != null) {
ctx.output(unmatchedFares, fareState.value)
fareState.clear()
}
if (rideState.value != null) {
ctx.output(unmatchedRides, rideState.value)
rideState.clear()
}
}
}
}