grpc-helper

gRPC helper

gRPC helper is an improved gRPC client with lots of helpful features.

Getting Started

Installing

npm i grpc-helper --save

or

yarn add grpc-helper

Features

• Promised unary & client stream call
• Client Load balance
• Service health checking
• Service discovery (static, dns srv)
• Circuit breaker based on Brakes
• Retry based on async-retry
• Metrics for prometheus based on prom-client
• Highly custom options

Usage

DNS Service discovery

const helper = new GRPCHelper({
  packageName: 'helloworld',
  serviceName: 'Greeter',
  protoPath: path.resolve(__dirname, './fixtures/hello.proto'),
  // intervalMs will determine how frequent the resolver lookup the records
  sdUri: 'dns://_grpc._tcp.greeter?intervalMs=5000',
});

await helper.waitForReady();

const res = await helper.SayHello({
  name: 'foo',
});

Static Service discovery

const helper = new GRPCHelper({
  packageName: 'helloworld',
  serviceName: 'Greeter',
  protoPath: path.resolve(__dirname, './fixtures/hello.proto'),
  sdUri: 'static://localhost:50051,localhost:50052,localhost:50053',
});

await helper.waitForReady();

const res = await helper.SayHello({
  name: 'foo',
});

Resolve with full response

const helper = new GRPCHelper({
  packageName: 'helloworld',
  serviceName: 'Greeter',
  protoPath: path.resolve(__dirname, './fixtures/hello.proto'),
  sdUri: 'static://localhost:50051',
  resolveFullResponse: true,
});

await helper.waitForReady();

const { message, peer, status, metadata } = await helper.SayHello({
  name: 'foo',
});

Client stream call

const stream = new stream.PassThrough({ objectMode: true });

const promise = helper.SayMultiHello(stream);

stream.write({
  name: 'foo1',
});

stream.write({
  name: 'foo2',
});

stream.write({
  name: 'foo3',
});

stream.end();

const result = await promise; // { message: 'hello foo1,foo2,foo3' }

Retry

const helper = new GRPCHelper({
  packageName: 'helloworld',
  serviceName: 'Greeter',
  protoPath: path.resolve(__dirname, './fixtures/hello.proto'),
  sdUri: 'static://localhost:50051',
  retryOpts: {
    enable: true,
    retries: 5,
    bailError(err, attempt) {
      // Just for example !!! It will not retry when code is 2
      return err.code === 2;
    },
  },
});

await helper.waitForReady();

await helper.SayHello({
  name: 'foo',
});

More

Please take a look at the test folder for more examples.

TODO

• Better api
• Doc
• Test code
• Retry on lb level when error
• Auto load proto when only one service available
• Consul/etcd/zk service discovery

License

This project is licensed under the MIT License - see the LICENSE file for details