loganknecht/grpc.ts.health.check

An implementation of gRPC health checks, written in typescript.

gRPC Health Check

An implementation of gRPC health checks, written in typescript.

It is assumed that you are using the grpc library.

Installation

npm install grpc-ts-health-check --save

Install the grpc library:

npm install grpc --save

Dependencies

• Google Protobuf: Protocol Buffers - Google's data interchange format.
• gRPC Boom: A zero dependency library to help create gRPC-friendly error objects.

Usage

Methods

Below is a list of available methods:

watch(request)

Set the initial status of the service and continues to watch for any changes.

• request - the HealthCheckRequest object.

const healthClient = new HealthClient(`${host}:${port}`, grpc.credentials.createInsecure());
const request = new HealthCheckRequest();
request.setService(serviceName);
const healthStream = healthClient.watch(request);
healthStream.on('data', (response: HealthCheckResponse) => {
  AppLogger.logger.debug(`Health Status: ${response.getStatus()}`);
});

check(request)

Checks the status of the service once.

• request - the HealthCheckRequest object.

const healthClient = new HealthClient(`${host}:${port}`, grpc.credentials.createInsecure());
const request = new HealthCheckRequest();
request.setService(serviceName);
healthClient.check(request, (error: Error | null, response: HealthCheckResponse) => {
  if (error) {
    AppLogger.logger.error('Health Check Failed', error);
  } else {
    AppLogger.logger.debug(`Health Status: ${response.getStatus()}`);
  }
});

Example

import * as grpc from 'grpc';
import { GrpcHealthCheck, HealthCheckResponse, HealthService } from 'grpc-ts-health-check';

const serviceName = 'auth.Authenticator';
const healthCheckStatusMap = {
  serviceName: HealthCheckResponse.ServingStatus.UNKNOWN
};

function start(): grpc.Server {
  // Create the server
  const server: grpc.Server = new grpc.Server();

  // Register the health service
  const grpcHealthCheck = new GrpcHealthCheck(healthCheckStatusMap);
  server.addService(HealthService, grpcHealthCheck);

  // Bind and start the server
  server.bind('localhost:9090', grpc.ServerCredentials.createInsecure());
  server.start();

  // Create the health client
  const healthClient = new HealthClient(`${host}:${port}`, grpc.credentials.createInsecure());
  const request = new HealthCheckRequest();
  request.setService(serviceName);

  // Watch health status - streaming request
  // This will set the initial health status
  // and continue to watch the service for changes.
  const healthStream = healthClient.watch(request);
  healthStream.on('data', (response: HealthCheckResponse) => {
    AppLogger.logger.debug(`Authenticator Service: Health Status: ${response.getStatus()}`);
  });

  // Check health status - single request
  // This will provide the current health status
  // of the service when the request is executed.
  setTimeout(() => {
    healthClient.check(request, (error: Error | null, response: HealthCheckResponse) => {
      if (error) {
        AppLogger.logger.error('Authenticator Service: Health Check Failed', error);
      } else {
        AppLogger.logger.debug(
          `Authenticator Service: Health Check Status: ${response.getStatus()}`
        );
      }
    });
  }, 5000);
  return server;
}