Add kxrpc grpc plugin

plugins/gradle.properties

@@ -3,6 +3,7 @@ exposed=0.+
 h2=2.3.+
 koin=3.5.+
 kotlinx-rpc=0.9.1
+kotlinx-rpc-grpc=0.10.0-grpc-121
 kotlinx-html=0.+
 mongo=4.10.+
 postgres=42.7.+

plugins/server/org.jetbrains/kotlinx-rpc-grpc/3.0/SampleServiceImpl.kt

@@ -0,0 +1,5 @@
+class SampleServiceImpl : SampleService {
+    override suspend fun greeting(name: ClientGreeting): ServerGreeting {
+        return ServerGreeting { content = "Hello, ${name.name}!" }
+    }
+}

plugins/server/org.jetbrains/kotlinx-rpc-grpc/3.0/documentation.md

@@ -0,0 +1,70 @@
+Add gRPC services to your Ktor application!
+
+# Usage
+
+## DISCLAIMER
+**This is a dev preview of the kotlinx-rpc gRPC plugin for Ktor. It is not yet ready for production use.
+The artifacts provided are dev artifacts, and the API may and will change in the future.**
+
+**Please use it to play with the plugin. We will appreciate any feedback on the 
+[Github](https://github.com/Kotlin/kotlinx-rpc/issues) 
+or in [Slack](https://kotlinlang.slack.com/archives/C072YJ3Q91V)**
+
+## gRPC Server
+You can add gRPC services to your Ktor application by using the `grpc` function provided by the plugin. 
+Here's an example:
+
+Declare a service in a `.proto` file.
+```protobuf
+syntax = "proto3";
+
+message ClientGreeting {
+  string name = 1;
+}
+
+message ServerGreeting {
+  string content = 2;
+}
+
+service SampleService {
+  rpc greeting(ClientGreeting) returns (ServerGreeting);
+}
+```
+
+The `SampleService` interface will generated for you alongside with other types and helper declarations. 
+
+Define an implementation. Then register it on the server and all done:
+
+```kotlin
+class SampleServiceImpl : SampleService {
+    override suspend fun greeting(name: ClientGreeting): ServerGreeting {
+        return ServerGreeting { content = "Hello, ${name.name}!" }
+    }
+}
+
+fun Application.module() {
+    grpc {
+        registerService<SampleService> { SampleServiceImpl() }
+    }
+}
+```
+
+## gRPC Client
+You can use any gRPC client on the other end, but also you can use ours!
+
+To do that - use the `GrpcClient` class:
+```Kotlin
+val client = GrpcClient("localhost", 8081) {
+    usePlaintext()
+}
+
+val response = client.withService<SampleService>().greeting(
+    ClientGreeting {
+        name = "Alex"
+    }
+)
+
+assertEquals("Hello, Alex!", response.content, "Wrong response message")
+
+client.close()
+```

plugins/server/org.jetbrains/kotlinx-rpc-grpc/3.0/inside_app.kt

@@ -0,0 +1,9 @@
+import io.ktor.server.application.Application
+import kotlinx.rpc.grpc.ktor.server.grpc
+import kotlinx.rpc.registerService
+
+fun Application.install() {
+    grpc {
+        registerService<SampleService> { SampleServiceImpl() }
+    }
+}

plugins/server/org.jetbrains/kotlinx-rpc-grpc/3.0/manifest.ktor.yaml

@@ -0,0 +1,38 @@
+name: gRPC
+description: Add gRPC services to your Ktor server with kotlinx.rpc
+vcsLink: https://github.com/Kotlin/kotlinx-rpc
+license: Apache 2.0
+category: Frameworks
+maven:
+  disabled: true
+# TODO KRPC-131 waiting for fixes to enable amper support
+amper:
+  disabled: true
+gradle:
+  pluginRepositories:
+    - url: https://maven.pkg.jetbrains.space/public/p/krpc/grpc
+  repositories:
+    - url: https://maven.pkg.jetbrains.space/public/p/krpc/grpc
+  plugins:
+    - id: org.jetbrains.kotlinx.rpc.plugin
+      version: $kotlinx-rpc-grpc
+installation:
+  inside_app: inside_app.kt
+  test_function: test.kt
+  gradle_build: |-
+    rpc {
+        grpc()
+    }
+sources:
+  - SampleServiceImpl.kt
+
+# I need src/main/proto structure
+#
+#mainSourceSet:
+#  - proto/service.proto
+
+# Or Maybe?
+#src:
+#  - main:
+#      - proto:
+#          - proto/service.proto

plugins/server/org.jetbrains/kotlinx-rpc-grpc/3.0/proto/service.proto

@@ -0,0 +1,15 @@
+syntax = "proto3";
+
+package io.ktor;
+
+message ClientGreeting {
+  string name = 1;
+}
+
+message ServerGreeting {
+  string content = 2;
+}
+
+service SampleService {
+  rpc greeting(ClientGreeting) returns (ServerGreeting);
+}

plugins/server/org.jetbrains/kotlinx-rpc-grpc/3.0/stub.kt

@@ -0,0 +1,21 @@
+// DO NOT DELETE, not included in generation, but is used for code highlighting in registry
+
+class ClientGreeting {
+    var name: String = ""
+
+    companion object {
+        operator fun invoke(body: ClientGreeting.() -> Unit): ClientGreeting = ClientGreeting().apply(body)
+    }
+}
+
+class ServerGreeting {
+    var content: String = ""
+
+    companion object {
+        operator fun invoke(body: ServerGreeting.() -> Unit): ServerGreeting = ServerGreeting().apply(body)
+    }
+}
+
+interface SampleService {
+    suspend fun greeting(name: ClientGreeting): ServerGreeting
+}

plugins/server/org.jetbrains/kotlinx-rpc-grpc/3.0/test.kt

@@ -0,0 +1,36 @@
+import io.ktor.server.testing.testApplication
+import kotlinx.rpc.grpc.GrpcClient
+import kotlinx.rpc.grpc.ktor.server.grpc
+import kotlinx.rpc.registerService
+import kotlinx.rpc.withService
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.time.Duration.Companion.minutes
+
+class ApplicationRpcTest {
+    @Test
+    fun testRpc() = testApplication {
+        application {
+            grpc(8081) {
+                registerService<SampleService> { SampleServiceImpl() }
+            }
+        }
+
+        startApplication()
+
+        val client = GrpcClient("localhost", 8081) {
+            usePlaintext()
+        }
+
+        val response = client.withService<SampleService>().greeting(
+            ClientGreeting {
+                name = "Alex"
+            }
+        )
+
+        assertEquals("Hello, Alex!", response.content, "Wrong response message")
+
+        client.shutdown()
+        client.awaitTermination(1.minutes)
+    }
+}

plugins/server/org.jetbrains/kotlinx-rpc-grpc/versions.ktor.yaml

@@ -0,0 +1,4 @@
+"[3.0,)":
+  - org.jetbrains.kotlinx:kotlinx-rpc-grpc-ktor-server:$kotlinx-rpc-grpc
+  - io.grpc:grpc-netty:1.73.0
+  - io.grpc:grpc-kotlin-stub:1.4.1