This is a prototype of akka-stream compatible Sink for Clickhouse database. Main features:
- Can transparently write any case class (if key names and types match).
- has batching, back-pressure and stuff.
- supports Array, Nested data types
- nullable fields
TODO:
- moar testing
Build artifacts are available on maven-central for Scala 2.12 and 2.13. For SBT, add this snippet to build.sbt:
libraryDependencies += "io.findify" %% "clickhouse-akka-stream" % "0.5.0"Writing rows to database:
import akka.actor.ActorSystem
import akka.stream.ActorMaterializer
import akka.stream.scaladsl.{Sink, Source}
import io.findify.clickhouse.ClickhouseSink
import io.findify.clickhouse.format.encoder.generic._
import io.findify.clickhouse.format.encoder.generic.auto._
class WriteExample {
def main(args: Array[String]): Unit = {
implicit val system = ActorSystem.create("clickhouse")
implicit val mat = ActorMaterializer()
case class Simple(key: String, value: Int)
implicit val encoder = deriveEncoder[Simple]
val source = Source(List(Simple("a", 1), Simple("b", 2), Simple("c", 3)))
.map(_.asRow)
val sink = Sink.fromGraph(new ClickhouseSink(
host = "localhost",
port = 8123,
table = "simple"
))
val result = source.runWith(sink)
// will perform:
// INSERT INTO simple FORMAT JSONEachRow
// {"key": "a", "value": 1}
// {"key": "b", "value": 2}
// {"key": "c", "value": 3}
}
}Reading rows from database:
import akka.actor.ActorSystem
import akka.stream.ActorMaterializer
import io.findify.clickhouse.ClickhouseClient
import io.findify.clickhouse.format.decoder.generic._
import io.findify.clickhouse.format.decoder.generic.auto._
class ReadExample {
def main(args: Array[String]): Unit = {
implicit val system = ActorSystem.create("clickhouse")
implicit val mat = ActorMaterializer()
import system.dispatcher
case class Simple(key: String, value: Int)
implicit val decoder = deriveDecoder[Simple]
val client = new ClickhouseClient(host = "localhost", port = 8123)
for {
ddl <- client.execute("create table simple(key String, value Int32) ENGINE = Memory")
insert <- client.execute("""insert into simple values ("a",1),("b",2)""")
rows <- client.query("select * from simple order by value asc").map(_.data.map(_.as[Simple]))
} yield {
println(rows)
// will print: List(Simple("a",1), Simple("b",2))
}
}
}The MIT License (MIT)
Copyright (c) 2022 Findify AB
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