gRPC Elixir

An Elixir implementation of gRPC.

Table of contents

• Notice
• Installation
• Usage
• Features
• Benchmark
• Contributing

Notice

Note The Gun library doesn't have a full 2.0 release yet, so we depend on :grcp_gun 2.0.1 for now. This is the same as :gun 2.0.0-rc.2, but Hex doesn't let us depend on RC versions for releases.

Installation

The package can be installed as:

def deps do
  [
    {:grpc, "~> 0.5.0"},
    # We don't force protobuf as a dependency for more
    # flexibility on which protobuf library is used,
    # but you probably want to use it as well
    {:protobuf, "~> 0.11"}
  ]
end

Usage

1. Generate Elixir code from proto file as protobuf-elixir shows(especially the gRPC Support section).

2. Implement the server side code like below and remember to return the expected message types.

defmodule Helloworld.Greeter.Server do
  use GRPC.Server, service: Helloworld.Greeter.Service

  @spec say_hello(Helloworld.HelloRequest.t, GRPC.Server.Stream.t) :: Helloworld.HelloReply.t
  def say_hello(request, _stream) do
    Helloworld.HelloReply.new(message: "Hello #{request.name}")
  end
end

3. Start the server

You can start the gRPC server as a supervised process. First, add GRPC.Server.Supervisor to your supervision tree.

# Define your endpoint
defmodule Helloworld.Endpoint do
  use GRPC.Endpoint

  intercept GRPC.Server.Interceptors.Logger
  run Helloworld.Greeter.Server
end

# In the start function of your Application
defmodule HelloworldApp do
  use Application
  def start(_type, _args) do
    children = [
      # ...
      {GRPC.Server.Supervisor, endpoint: Helloworld.Endpoint, port: 50051}
    ]

    opts = [strategy: :one_for_one, name: YourApp]
    Supervisor.start_link(children, opts)
  end
end

4. Call rpc:

iex> {:ok, channel} = GRPC.Stub.connect("localhost:50051")
iex> request = Helloworld.HelloRequest.new(name: "grpc-elixir")
iex> {:ok, reply} = channel |> Helloworld.Greeter.Stub.say_hello(request)

# With interceptors
iex> {:ok, channel} = GRPC.Stub.connect("localhost:50051", interceptors: [GRPC.Client.Interceptors.Logger])
...

Check examples and interop(Interoperability Test) for some examples.

Features

• Various kinds of RPC:
  • Unary
  • Server-streaming
  • Client-streaming
  • Bidirectional-streaming
• TLS Authentication
• Error handling
• Interceptors(See GRPC.Endpoint)
• Connection Backoff
• Data compression

Benchmark

1. Simple benchmark by using ghz

2. Benchmark followed by official spec

Contributing

Your contributions are welcome!

Please open issues if you have questions, problems and ideas. You can create pull requests directly if you want to fix little bugs, add small features and so on. But you'd better use issues first if you want to add a big feature or change a lot of code.