Stream Driven Development - Design your data pipeline with Akka Streams

Slide 1

Slide 1 text

Slide 2

Slide 2 text

Slide 3

Slide 3 text

Slide 4

Slide 4 text

Slide 5

Slide 5 text

Slide 6

Slide 6 text

Slide 7

Slide 7 text

Slide 8

Slide 8 text

Slide 9

Slide 9 text

Slide 10

Slide 10 text

Slide 11

Slide 11 text

Slide 12

Slide 12 text

© 2018 HOMEAWAY. ALL RIGHTS RESERVED. 12 SOURCE (1 output) FAN-IN (n inputs, 1 output) FAN-OUT (1 input, n outputs) RUNNABLEGRAPH (no input or output) STREAMS STAGES FLOW (1 input, 1 output) SINK (1 input) ... CUSTOM

Slide 13

Slide 13 text

© 2018 HOMEAWAY. ALL RIGHTS RESERVED. 13 Source ~> Flow = Source Flow ~> Sink = Sink Flow ~> Flow = Flow Broadcast ~> Merge = Flow Source ~> Sink = RunnableGraph Source ~> Flow ~> Sink = RunnableGraph STAGE ARITHMETIC

Slide 14

Slide 14 text

Slide 15

Slide 15 text

Slide 16

Slide 16 text

Slide 17

Slide 17 text

Slide 18

Slide 18 text

Slide 19

Slide 19 text

Slide 20

Slide 20 text

Slide 21

Slide 21 text

Slide 22

Slide 22 text

Slide 23

Slide 23 text

Slide 24

Slide 24 text

Slide 25

Slide 25 text

Slide 26

Slide 26 text

Slide 27

Slide 27 text

Slide 28

Slide 28 text

Slide 29

Slide 29 text

Slide 30

Slide 30 text

© 2018 HOMEAWAY. ALL RIGHTS RESERVED. 30 SIDE EFFECTS Error Handling Logging Monitoring EVENTS Errors Audit ... ... REFERENTIALLY TRANSPARENT STAGES Flow[In, Either[Error, Out], Mat] Flow[In, (Seq[Audit], Out), Mat] Flow[(Offset,In), (Offset, Out), Mat] ...

Slide 31

Slide 31 text

Flow[PropertyChange, Either[ValidationError, AdwordsChange], NotUsed] Source[PropertyChange, NotUsed] Sink[AdwordsChange, Future[Done]] RunnableGraph[Future[Done]] Sink[ValidationError, NotUsed]

Slide 32

Slide 32 text

Flow[PropertyChange, Either[ValidationError, AdwordsChange], NotUsed] Source[PropertyChange, NotUsed] Flow[AdwordsChange, Either[StorageError, Stored], NotUsed] RunnableGraph[Future[Done]] Sink[Error, NotUsed] Sink[Stored, Future[Done]]

Slide 33

Slide 33 text

Slide 34

Slide 34 text

Slide 35

Slide 35 text

def propertySource(config: KafkaConfig): Source[PropertyChange, NotUsed] = { def settings(config: KafkaConfig): ConsumerSettings[String, PropertyChange] = ??? val kafkaSrc: Source[ConsumerRecord[String, PropertyChange], Control] = Consumer.plainSource( settings(config), Subscriptions.topics(config.topic) ) kafkaSrc .map(_.value) .mapMaterializedValue { _ ⇒ NotUsed } } SOURCE

Slide 36

Slide 36 text

Slide 37

Slide 37 text

Slide 38

Slide 38 text

Slide 39

Slide 39 text

def processingFlow(): Flow[PropertyChange, Either[ValidationError, AdwordsChange], NotUsed] = { val service: PropertyProcessingService = ??? Flow.fromFunction(service.process) } PROCESSING FLOW

Slide 40

Slide 40 text

def processingFlow(): Flow[PropertyChange, Either[ValidationError, AdwordsChange], NotUsed] = { val validationService : PropertyValidationService = ??? val transformationService: PropertyTransformationService = ??? Flow.fromFunction(validationService.validate) .async .map(transformationService.transform) } PROCESSING FLOW

Slide 41

Slide 41 text

Slide 42

Slide 42 text

STORING FLOW def adwordsFlow(config: AdwordsConfig): Flow[AdwordsChange, Either[StorageError, Stored], NotUsed] = { val service: AdwordsService = ??? Flow[AdwordsChange].mapAsync(config.parallelism)(service.store) }

Slide 43

Slide 43 text

STORING FLOW - WITH THROTTLING def adwordsFlow(config: AdwordsConfig): Flow[AdwordsChange, Either[StorageError, Stored], NotUsed] = { val service: AdwordsService = ??? Flow[AdwordsChange] .throttle(50, per = 1.second, maximumBurst = 50, mode = Shaping) .mapAsync(config.parallelism)(service.store) }

Slide 44

Slide 44 text

STORING FLOW - WITH BATCHING def adwordsFlow(config: AdwordsConfig): Flow[AdwordsChange, Either[StorageError, Stored], NotUsed] = { val service: AdwordsService = ??? Flow[AdwordsChange] .batch(max = 5000, seed = List(_))(_ :+ _) .throttle(50, per = 1.second, maximumBurst = 50, mode = Shaping) .mapAsync(config.parallelism)(service.store) }

Slide 45

Slide 45 text

Slide 46

Slide 46 text

ERROR SINK def errorSink(cfg: ErrorConfig): Sink[AdwordsStreamError, NotUsed] = { val service: AdwordsErrorService = ??? Sink.foreach[AdwordsStreamError](service.handle) .mapMaterializedValue(_ ⇒ NotUsed) }

Slide 47

Slide 47 text

Slide 48

Slide 48 text

def graph(source : Source[PropertyChange, NotUsed], process : Flow[PropertyChange, Either[ValidationError, AdwordsChange], NotUsed], store : Flow[AdwordsChange, Either[StorageError, Stored], NotUsed], errorSink: Sink[AdwordsStreamError, NotUsed]): RunnableGraph[Future[Done]] = { val processAndDivert: Flow[PropertyChange, AdwordsChange, NotUsed] = process via divertErrors(to = errorSink) val storeAndDivert: Flow[AdwordsChange, Stored, NotUsed] = store via divertErrors(to = errorSink) source .via(processAndDivert) .via(storeAndDivert) .toMat(Sink.ignore)(Keep.right) } GRAPH

Slide 49

Slide 49 text

Slide 50

Slide 50 text

Slide 51

Slide 51 text

Slide 52

Slide 52 text

Slide 53

Slide 53 text

def divertErrors[T, E, M](sink: Sink[E, M]): Flow[Either[E, T], T, M] = Flow[Either[E, T]] .divertToMat(sink.contramap(_.left.get), when = _.isLeft)(Keep.right) .map(_.right.get) GRAPH - DIVERT ERRORS

Slide 54

Slide 54 text

def divertErrors[T, E, M](to: Sink[E, M]): Flow[Either[E, T], T, M] = { Flow.fromGraph(GraphDSL.create(to) { implicit b ⇒ sink ⇒ val partition = b.add(Partition[Either[E, T]](2, _.fold(_ ⇒ 0, _ ⇒ 1))) val left = b.add(Flow[Either[E, T]].map (_.left.get)) val right = b.add(Flow[Either[E, T]].map (_.right.get)) partition ~> left ~> sink partition ~> right FlowShape(partition.in, right.out) }) } GRAPH - DIVERT ERRORS (ante 2.5.10)

Slide 55

Slide 55 text

© 2018 HOMEAWAY. ALL RIGHTS RESERVED. 55 PropertyProcessingService def process(p: PropertyChange): Either[ValidationError, AdwordsChange] PropertyChange AdwordsService def store(p: AdwordsChange): Future[Either[StorageError, Stored]] DOMAIN ValidationError AdwordsChange Stored StorageError AdwordsErrorService def handle(p: AdwordsError): Unit

Slide 56

Slide 56 text

Slide 57

Slide 57 text

Slide 58

Slide 58 text

Slide 59

Slide 59 text

Slide 60

Slide 60 text

Slide 61

Slide 61 text

"application" should "run the stream" in { Application.run() eventually { // verify side-effects } } END TO END TEST

Slide 62

Slide 62 text

Slide 63

Slide 63 text

"graph" should "connect the provided stages" in { val changesOfMixedValidity: List[PropertyChange] = ??? val source = Source(changesOfMixedValidity) val processingFlow = Flow[PropertyChange].map { ??? } val storingFlow = Flow[AdwordsChange].map { ??? } val errorSink = Flow[Error].map { ??? }.to(Sink.ignore) Graph(source, processingFlow, storingFlow, errorSink).run().futureValue // verify side-effects } GRAPH TEST

Slide 64

Slide 64 text

Slide 65

Slide 65 text

"property change source" should "read events from Kafka" in { val change: PropertyChange = ??? val config: KafkaConfig = ??? val kafka = new EmbeddedKafka(config) kafka.publish(config.topic, change) val source = PropertySource(config) source.runWith(TestSink.probe) .request(1) .expectNext(change) } STAGE TEST - SOURCE

Slide 66

Slide 66 text

Slide 67

Slide 67 text

"property change source" should "read events from Kafka" in { val change: PropertyChange = ??? val config: KafkaConfig = ??? val kafka = new EmbeddedKafka(config) kafka.publish(config.topic, change) val source = PropertySource(config) val result: Future[PropertyChange] = source.runWith(Sink.head) result.futureValue shouldBe Some(change) } STAGE TEST - SOURCE

Slide 68

Slide 68 text

"property change source" should "read events from Kafka" in { val change: PropertyChange = ??? val config: KafkaConfig = ??? val kafka = new EmbeddedKafka(config) kafka.publish(config.topic, change) val source = PropertySource(config) val result: Future[Seq[PropertyChange]] = source.take(2) .runWith(Sink.seq) result.futureValue shouldBe Seq(change1, change2) } STAGE TEST - SOURCE