gRPC

The gRPC is an interface that helps interact with both the Write Side and the Read Side using gRPC service calls.

Implementation

• Define your gRPC services as explained here

• Add the following lines to your build.sbt file:

PB.protoSources in Compile := Seq(file(<path-to-your-proto-definitions>))
PB.includePaths in Compile ++= Seq(file(<path-to-your-include>))
akkaGrpcGeneratedLanguages := Seq(AkkaGrpc.Scala),
akkaGrpcExtraGenerators in Compile += PlayScalaServerCodeGenerator,
akkaGrpcExtraGenerators in Compile += PlayScalaClientCodeGenerator,
akkaGrpcCodeGeneratorSettings += "server_power_apis",
akkaGrpcCodeGeneratorSettings := akkaGrpcCodeGeneratorSettings.value.filterNot(_ == "flat_package")

• From the root folder of your project run sbt clean compile to generate the grpc scala traits.

• Implement the generated traits by injecting the following akka.cluster.sharding.typed.scaladsl.ClusterSharding and com.lightbend.lagom.scaladsl.persistence.PersistentEntityRegistry and mixed in with io.superflat.lagompb.BaseGrpcServiceImpl to be able to interact with the domain model implementation.

Example:

class AccountGrpcServiceImpl(
  sys: ActorSystem,
  val clusterSharding: ClusterSharding,
  val aggregateRoot: AggregateRoot
)(implicit ec: ExecutionContext)
    extends AbstractAccountGrpcServicePowerApiRouter(sys)
    with BaseGrpcServiceImpl{

    // your implementation goes in here
}