311 lines
9.7 KiB
Scala
311 lines
9.7 KiB
Scala
/*
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* Copyright (C) 2015 Typesafe Inc. <http://www.typesafe.com>
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*/
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package docs.persistence.query
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import akka.actor._
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import akka.persistence.{ Recovery, PersistentActor }
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import akka.persistence.query._
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import akka.stream.{ FlowShape, ActorMaterializer }
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import akka.stream.scaladsl.{ Flow, Sink, Source }
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import akka.stream.javadsl
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import akka.testkit.AkkaSpec
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import akka.util.Timeout
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import docs.persistence.query.PersistenceQueryDocSpec.{ DummyStore, TheOneWhoWritesToQueryJournal }
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import org.reactivestreams.Subscriber
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import scala.collection.immutable
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import scala.concurrent.Future
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import scala.concurrent.duration.FiniteDuration
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import scala.concurrent.duration._
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import com.typesafe.config.Config
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object PersistenceQueryDocSpec {
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implicit val timeout = Timeout(3.seconds)
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//#advanced-journal-query-types
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final case class RichEvent(tags: Set[String], payload: Any)
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// a plugin can provide:
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case class QueryMetadata(deterministicOrder: Boolean, infinite: Boolean)
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//#advanced-journal-query-types
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//#my-read-journal
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class MyReadJournalProvider(system: ExtendedActorSystem, config: Config)
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extends ReadJournalProvider {
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override val scaladslReadJournal: MyScaladslReadJournal =
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new MyScaladslReadJournal(system, config)
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override val javadslReadJournal: MyJavadslReadJournal =
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new MyJavadslReadJournal(scaladslReadJournal)
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}
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class MyScaladslReadJournal(system: ExtendedActorSystem, config: Config)
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extends akka.persistence.query.scaladsl.ReadJournal
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with akka.persistence.query.scaladsl.EventsByTagQuery
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with akka.persistence.query.scaladsl.EventsByPersistenceIdQuery
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with akka.persistence.query.scaladsl.AllPersistenceIdsQuery
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with akka.persistence.query.scaladsl.CurrentPersistenceIdsQuery {
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private val refreshInterval: FiniteDuration =
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config.getDuration("refresh-interval", MILLISECONDS).millis
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override def eventsByTag(
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tag: String, offset: Long = 0L): Source[EventEnvelope, Unit] = {
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val props = MyEventsByTagPublisher.props(tag, offset, refreshInterval)
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Source.actorPublisher[EventEnvelope](props)
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.mapMaterializedValue(_ ⇒ ())
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}
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override def eventsByPersistenceId(
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persistenceId: String, fromSequenceNr: Long = 0L,
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toSequenceNr: Long = Long.MaxValue): Source[EventEnvelope, Unit] = {
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// implement in a similar way as eventsByTag
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???
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}
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override def allPersistenceIds(): Source[String, Unit] = {
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// implement in a similar way as eventsByTag
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???
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}
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override def currentPersistenceIds(): Source[String, Unit] = {
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// implement in a similar way as eventsByTag
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???
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}
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// possibility to add more plugin specific queries
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//#advanced-journal-query-definition
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def byTagsWithMeta(tags: Set[String]): Source[RichEvent, QueryMetadata] = {
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//#advanced-journal-query-definition
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// implement in a similar way as eventsByTag
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???
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}
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}
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class MyJavadslReadJournal(scaladslReadJournal: MyScaladslReadJournal)
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extends akka.persistence.query.javadsl.ReadJournal
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with akka.persistence.query.javadsl.EventsByTagQuery
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with akka.persistence.query.javadsl.EventsByPersistenceIdQuery
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with akka.persistence.query.javadsl.AllPersistenceIdsQuery
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with akka.persistence.query.javadsl.CurrentPersistenceIdsQuery {
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override def eventsByTag(
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tag: String, offset: Long = 0L): javadsl.Source[EventEnvelope, Unit] =
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scaladslReadJournal.eventsByTag(tag, offset).asJava
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override def eventsByPersistenceId(
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persistenceId: String, fromSequenceNr: Long = 0L,
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toSequenceNr: Long = Long.MaxValue): javadsl.Source[EventEnvelope, Unit] =
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scaladslReadJournal.eventsByPersistenceId(
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persistenceId, fromSequenceNr, toSequenceNr).asJava
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override def allPersistenceIds(): javadsl.Source[String, Unit] =
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scaladslReadJournal.allPersistenceIds().asJava
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override def currentPersistenceIds(): javadsl.Source[String, Unit] =
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scaladslReadJournal.currentPersistenceIds().asJava
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// possibility to add more plugin specific queries
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def byTagsWithMeta(
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tags: java.util.Set[String]): javadsl.Source[RichEvent, QueryMetadata] = {
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import scala.collection.JavaConverters._
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scaladslReadJournal.byTagsWithMeta(tags.asScala.toSet).asJava
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}
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}
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//#my-read-journal
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case class ComplexState() {
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def readyToSave = false
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}
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case class Record(any: Any)
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class DummyStore { def save(record: Record) = Future.successful(42L) }
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val JournalId = "akka.persistence.query.my-read-journal"
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class X {
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def convertToReadSideTypes(in: Any): Any = ???
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object ReactiveStreamsCompatibleDBDriver {
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def batchWriter: Subscriber[immutable.Seq[Any]] = ???
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}
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//#projection-into-different-store-rs
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implicit val system = ActorSystem()
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implicit val mat = ActorMaterializer()
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val readJournal =
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PersistenceQuery(system).readJournalFor[MyScaladslReadJournal](JournalId)
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val dbBatchWriter: Subscriber[immutable.Seq[Any]] =
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ReactiveStreamsCompatibleDBDriver.batchWriter
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// Using an example (Reactive Streams) Database driver
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readJournal
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.eventsByPersistenceId("user-1337")
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.map(envelope => envelope.event)
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.map(convertToReadSideTypes) // convert to datatype
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.grouped(20) // batch inserts into groups of 20
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.runWith(Sink.fromSubscriber(dbBatchWriter)) // write batches to read-side database
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//#projection-into-different-store-rs
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}
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//#projection-into-different-store-actor
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class TheOneWhoWritesToQueryJournal(id: String) extends Actor {
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val store = new DummyStore()
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var state: ComplexState = ComplexState()
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def receive = {
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case m =>
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state = updateState(state, m)
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if (state.readyToSave) store.save(Record(state))
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}
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def updateState(state: ComplexState, msg: Any): ComplexState = {
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// some complicated aggregation logic here ...
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state
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}
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}
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//#projection-into-different-store-actor
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}
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class PersistenceQueryDocSpec(s: String) extends AkkaSpec(s) {
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import PersistenceQueryDocSpec._
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def this() {
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this(
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"""
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akka.persistence.query.my-read-journal {
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class = "docs.persistence.query.PersistenceQueryDocSpec$MyReadJournalProvider"
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refresh-interval = 3s
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}
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""")
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}
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implicit val mat = ActorMaterializer()
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class BasicUsage {
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//#basic-usage
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// obtain read journal by plugin id
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val readJournal =
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PersistenceQuery(system).readJournalFor[MyScaladslReadJournal](
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"akka.persistence.query.my-read-journal")
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// issue query to journal
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val source: Source[EventEnvelope, Unit] =
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readJournal.eventsByPersistenceId("user-1337", 0, Long.MaxValue)
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// materialize stream, consuming events
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implicit val mat = ActorMaterializer()
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source.runForeach { event => println("Event: " + event) }
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//#basic-usage
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//#all-persistence-ids-live
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readJournal.allPersistenceIds()
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//#all-persistence-ids-live
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//#all-persistence-ids-snap
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readJournal.currentPersistenceIds()
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//#all-persistence-ids-snap
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//#events-by-tag
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// assuming journal is able to work with numeric offsets we can:
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val blueThings: Source[EventEnvelope, Unit] =
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readJournal.eventsByTag("blue")
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// find top 10 blue things:
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val top10BlueThings: Future[Vector[Any]] =
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blueThings
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.map(_.event)
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.take(10) // cancels the query stream after pulling 10 elements
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.runFold(Vector.empty[Any])(_ :+ _)
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// start another query, from the known offset
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val furtherBlueThings = readJournal.eventsByTag("blue", offset = 10)
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//#events-by-tag
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//#events-by-persistent-id
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readJournal.eventsByPersistenceId("user-us-1337")
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//#events-by-persistent-id
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//#advanced-journal-query-usage
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val query: Source[RichEvent, QueryMetadata] =
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readJournal.byTagsWithMeta(Set("red", "blue"))
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query
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.mapMaterializedValue { meta =>
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println(s"The query is: " +
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s"ordered deterministically: ${meta.deterministicOrder}, " +
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s"infinite: ${meta.infinite}")
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}
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.map { event => println(s"Event payload: ${event.payload}") }
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.runWith(Sink.ignore)
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//#advanced-journal-query-usage
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}
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//#projection-into-different-store
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class MyResumableProjection(name: String) {
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def saveProgress(offset: Long): Future[Long] = ???
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def latestOffset: Future[Long] = ???
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}
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//#projection-into-different-store
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class RunWithActor {
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val readJournal =
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PersistenceQuery(system).readJournalFor[MyScaladslReadJournal](JournalId)
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//#projection-into-different-store-actor-run
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import akka.pattern.ask
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import system.dispatcher
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implicit val timeout = Timeout(3.seconds)
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val bidProjection = new MyResumableProjection("bid")
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val writerProps = Props(classOf[TheOneWhoWritesToQueryJournal], "bid")
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val writer = system.actorOf(writerProps, "bid-projection-writer")
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bidProjection.latestOffset.foreach { startFromOffset =>
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readJournal
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.eventsByTag("bid", startFromOffset)
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.mapAsync(8) { envelope => (writer ? envelope.event).map(_ => envelope.offset) }
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.mapAsync(1) { offset => bidProjection.saveProgress(offset) }
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.runWith(Sink.ignore)
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}
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//#projection-into-different-store-actor-run
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}
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class RunWithAsyncFunction {
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val readJournal =
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PersistenceQuery(system).readJournalFor[MyScaladslReadJournal](
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"akka.persistence.query.my-read-journal")
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//#projection-into-different-store-simple
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trait ExampleStore {
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def save(event: Any): Future[Unit]
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}
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//#projection-into-different-store-simple
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//#projection-into-different-store-simple
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val store: ExampleStore = ???
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readJournal
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.eventsByTag("bid")
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.mapAsync(1) { e => store.save(e) }
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.runWith(Sink.ignore)
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//#projection-into-different-store-simple
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}
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}
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