https://github.com/darvld/krpc

An idiomatic Kotlin gRPC library.
https://github.com/darvld/krpc

grpc kotlin

Last synced: about 1 year ago
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An idiomatic Kotlin gRPC library.

• Host: GitHub
• URL: https://github.com/darvld/krpc
• Owner: darvld
• License: apache-2.0
• Archived: true
• Created: 2021-07-04T19:59:22.000Z (over 4 years ago)
• Default Branch: main
• Last Pushed: 2022-05-14T00:13:27.000Z (almost 4 years ago)
• Last Synced: 2025-02-16T18:18:30.498Z (about 1 year ago)
• Topics: grpc, kotlin
• Language: Kotlin
• Homepage:
• Size: 391 KB
• Stars: 7
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE
  • Code of conduct: CODE_OF_CONDUCT.md

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README

          
# Kotlin RPC

[![CodeFactor](https://www.codefactor.io/repository/github/darvld/krpc/badge/main)](https://www.codefactor.io/repository/github/darvld/krpc/overview/main)

[![CI](https://github.com/darvld/krpc/actions/workflows/ci.yml/badge.svg)](https://github.com/darvld/krpc/actions/workflows/ci.yml)

[![Maven Central](https://img.shields.io/maven-central/v/io.github.darvld.krpc/krpc-runtime.svg?label=Maven%20Central)](https://search.maven.org/search?q=g:%22io.github.darvld.krpc%22%20AND%20a:%22krpc-runtime%22)

A Kotlin Multiplatform library to generate and consume gRPC services directly from Kotlin. Check out

the [Sample project](https://github.com/darvld/krpc/tree/main/sample) to see a full list of available features, or see

the [Quick Start](docs/Basic.md) guide on how to add kRPC to your project.

> **Note:** At the moment, only Kotlin/JVM is supported as a target platform for code generation.

## Overview

Instead of using Protoc and .proto files to define services, kRPC uses Kotlin's interfaces and annotations. Any

interface annotated with `@Service` will be recognized as a definition by the kRPC compiler:

```kotlin

@Service

interface GpsService {

    @UnaryCall

    suspend fun locationForVehicle(vehicle: Vehicle): Location

}

```

The methods inside the service definitions should have the proper annotation to reflect the type of RPC call:

- `@UnaryCall` defines a single-request, single-response rpc method, suspending until the server replies.

- `@ServerStream` takes a single request and returns a response `Flow`, which you can later use to consume the responses

  streamed by the server. Server-stream methods don't suspend, instead the returned flow collector will suspend until

  the first value is received.

- `@ClientStream` takes a request flow and returns a single response, suspending until it is received.

- `@BidiStream` takes a request flow and returns response flow, thus enabling bidirectional streaming. Like

  with `@ServerStream`, this method does not suspend.

Method parameters and return types must be serializable.

The compiler will then generate two implementations of this interface: an abstract service provider, and a client.

Additionally, a helper class is generated: the service's Descriptor, which contains all the generated method

descriptors (on JVM) and can be used to create your own custom client/server implementations.

## Implementation

The kRPC compiler uses Google's [KSP](https://github.com/google/ksp) to process the annotations and then generates code

with [KotlinPoet](). On JVM, the runtime and generated stubs are implemented on top of

the [grpc-kotlin-stub](https://github.com/grpc/grpc-kotlin)

runtime.

## Resources

- [Getting Started](docs/Basic.md)

- [Service Definitions](docs/Advanced.md)

- [Roadmap](docs/Roadmap.md)

If you find the project useful, have an idea on how to improve it or if you find a bug, consider making a contribution

or opening a new issue. Pull requests are welcome.