GRPC interceptor support

[jayMedicalChain]

Feature Request

Problem

I have created multiple NestJs servers that communicate via GRPC. When deploying my services with docker i get an intermittent connection issues from GRPC ECONNRESET [{"message":"14 UNAVAILABLE: read ECONNRESET"}]. Judging by this issue posted on the @grpc/grpc-node it seems this is an issue with the library.

grpc/grpc-node#1907 (comment)

Solution i would like

Advice i got from posting on the node-grpc issue thread was to create an interceptor to retry requests, looking at the GrpcOptions within nest, nest does not allow for interceptors. A simple way allowing interceptors would be a nice feature to have.

information about interceptors can be found here

https://github.com/grpc/proposal/blob/master/L5-node-client-interceptors.md#examples

Teachability, Documentation, Adoption, Migration Strategy

Ideally you would be able to pass interceptors as options like so

export const grpcOptions: GrpcOptions = {
  transport: Transport.GRPC,
  options: {
     interceptors: [someInterceptor],
    url: `${env.SERVER_HOST}:${config.gateway.port}`,
    package: [
      config.gateway.users.v1.package,
      config.gateway.records.v1.package,
    ],
    protoPath: [
      config.gateway.users.v1.protoPath,
      config.gateway.records.v1.protoPath,
    ],
    loader: {
      includeDirs: [config.protoLoaderDir],
      arrays: true,
      enums: String,
    },
  },
};

What is the motivation / use case for changing the behavior?

Having these sort of intermittent issues that make API calls sporadically fail without a way to easily implement retries isn't great.

[kamilmysliwiec]

looking at the GrpcOptions within nest, nest does not allow for interceptors.

We might need to just update the interface given that the options object is actually passed down to the @grpc/grpc-node package.

[jayMedicalChain]

I can confirm it is just a case of updating the interface, i have just tested and passing an an interceptor into the options via the interceptors property, like so, works fine.

const clientOptions: ClientsModuleOptions = [
  {
    name: "HP_USERS_PACKAGE",
    //@ts-ignore
    transport: Transport.GRPC,
    options: {
      channelOptions: {
        //@ts-ignore
        interceptors: [interceptor],
      },
      url: `${env.USERS_SERVICE}:${config.users.port}`,
      package: [config.users.users.v1.package],
      protoPath: [config.users.users.v1.protoPath],
      loader: {
        includeDirs: [config.protoLoaderDir],
        enums: String,
        arrays: true,
      },
    },
  },
];

[kamilmysliwiec]

Would you like to create a PR to address this issue?

[Jaypov]

sure thing, ill get it done either later today or tomorrow.

[kamilmysliwiec]

Let's track this here #8231

[vietkute02]

This pull request expose interceptors option for grpc but it not pass this options to grpc-js client

[wdhxs]

I can confirm it is just a case of updating the interface, i have just tested and passing an an interceptor into the options via the interceptors property, like so, works fine.

const clientOptions: ClientsModuleOptions = [
  {
    name: "HP_USERS_PACKAGE",
    //@ts-ignore
    transport: Transport.GRPC,
    options: {
      channelOptions: {
        //@ts-ignore
        interceptors: [interceptor],
      },
      url: `${env.USERS_SERVICE}:${config.users.port}`,
      package: [config.users.users.v1.package],
      protoPath: [config.users.users.v1.protoPath],
      loader: {
        includeDirs: [config.protoLoaderDir],
        enums: String,
        arrays: true,
      },
    },
  },
];

Hi~We have also encountered this problem recently. And we did it according to your method, but this interceptor did not be executed.
options: { channelOptions: { interceptors: [retryInterceptor], }, }
And the retryInterceptor is same as retry from https://github.com/grpc/proposal/blob/master/L5-node-client-interceptors.md#examples
Could you tell me why?Thanks!