feat: Access to gRPC clients in through workflow context (#2281)

Author: johanandren

project/Dependencies.scala

@@ -76,7 +76,8 @@ object Dependencies {
 
   val scalapbCompilerPlugin = "com.thesamet.scalapb" %% "compilerplugin" % scalapb.compiler.Version.scalapbVersion
   val scalaPbValidateCore = "com.thesamet.scalapb" %% "scalapb-validate-core" % "0.3.4"
-  val sbtProtoc = "com.thesamet" % "sbt-protoc" % "1.0.0"
+  // keep aligned with the sbt-protoc plugin version in plugins.sbt
+  val sbtProtoc = "com.thesamet" % "sbt-protoc" % "1.0.3"
 
   val akkaGrpc = "com.lightbend.akka.grpc" % "sbt-akka-grpc" % akka.grpc.gen.BuildInfo.version
   val scalaCollectionCompat = "org.scala-lang.modules" %% "scala-collection-compat" % "2.10.0"

project/plugins.sbt

@@ -12,3 +12,6 @@ addSbtPlugin("com.github.sbt" % "sbt-ci-release" % "1.5.12")
 addSbtPlugin("net.aichler" % "sbt-jupiter-interface" % "0.11.0")
 addSbtPlugin("com.thesamet" % "sbt-protoc" % "1.0.3")
 addSbtPlugin("com.thoughtworks.sbt-api-mappings" % "sbt-api-mappings" % "3.0.2")
+
+// force bumped because of CI not finding 1.0.0 which was the transitive version
+addSbtPlugin("org.portable-scala" % "sbt-platform-deps" % "1.0.2")

sdk/java-sdk-protobuf/src/main/java/kalix/javasdk/workflow/WorkflowContext.java

@@ -13,4 +13,17 @@ public interface WorkflowContext extends Context {
    * @return The workflow id.
    */
   String workflowId();
+
+  /**
+   * Get an Akka gRPC client for the given service name. The same client instance is shared across
+   * components in the application. The lifecycle of the client is managed by the SDK and it should
+   * not be stopped by user code.
+   *
+   * @param <T> The "service" interface generated for the service by Akka gRPC
+   * @param clientClass The class of a gRPC service generated by Akka gRPC
+   * @param service The name of the service to connect to, either a name of another Kalix service or
+   *     an external service where connection details are configured under
+   *     `akka.grpc.client.[service-name]` in `application.conf`.
+   */
+  <T> T getGrpcClient(Class<T> clientClass, String service);
 }

sdk/java-sdk-protobuf/src/main/scala/kalix/javasdk/impl/workflow/WorkflowImpl.scala

@@ -361,8 +361,16 @@ private[kalix] final class CommandContextImpl(
     system: ActorSystem)
     extends AbstractContext(system)
     with CommandContext
-    with ActivatableContext
+    with ActivatableContext {
+  override def getGrpcClient[T](clientClass: Class[T], service: String): T =
+    GrpcClients(system).getGrpcClient(clientClass, service)
+
+}
 
 private[kalix] final class WorkflowContextImpl(override val workflowId: String, system: ActorSystem)
     extends AbstractContext(system)
-    with WorkflowContext
+    with WorkflowContext {
+  override def getGrpcClient[T](clientClass: Class[T], service: String): T =
+    GrpcClients(system).getGrpcClient(clientClass, service)
+
+}

sdk/scala-sdk-protobuf/src/main/scala/kalix/scalasdk/impl/workflow/WorkflowAdapters.scala

@@ -203,6 +203,9 @@ private[scalasdk] final class ScalaCommandContextAdapter(val javaSdkContext: jav
     case ctx: javasdk.impl.AbstractContext => ctx.getComponentGrpcClient(serviceClass)
   }
 
+  override def getGrpcClient[T](clientClass: Class[T], service: String): T =
+    javaSdkContext.getGrpcClient(clientClass, service)
+
   override def materializer(): Materializer = javaSdkContext.materializer()
 
   override def workflowId: String = javaSdkContext.workflowId()
@@ -211,6 +214,9 @@ private[scalasdk] final class ScalaCommandContextAdapter(val javaSdkContext: jav
 private[scalasdk] final class ScalaWorkflowContextAdapter(javaSdkContext: javasdk.workflow.WorkflowContext)
     extends WorkflowContext {
 
+  override def getGrpcClient[T](clientClass: Class[T], service: String): T =
+    javaSdkContext.getGrpcClient(clientClass, service)
+
   override def materializer(): Materializer = javaSdkContext.materializer()
 
   override def workflowId: String = javaSdkContext.workflowId()

sdk/scala-sdk-protobuf/src/main/scala/kalix/scalasdk/workflow/WorkflowContext.scala

@@ -15,4 +15,19 @@ trait WorkflowContext extends Context {
    *   The workflow id.
    */
   def workflowId: String
+
+  /**
+   * Get an Akka gRPC client for the given service name. The same client instance is shared across components in the
+   * application. The lifecycle of the client is managed by the SDK and it should not be stopped by user code.
+   *
+   * @tparam T
+   *   The "service" interface generated for the service by Akka gRPC
+   * @param clientClass
+   *   The class of a gRPC service generated by Akka gRPC
+   * @param service
+   *   The name of the service to connect to, either a name of another Kalix service or an external service where
+   *   connection details are configured under `akka.grpc.client.[service-name]` in `application.conf`.
+   */
+  def getGrpcClient[T](clientClass: Class[T], service: String): T
+
 }