Nest-consul-loadbalance NPM

Description

A component of nestcloud. NestCloud is a nest framework micro-service solution.

This is a software load balancers primary for rest calls.

Installation

$ npm i --save nest-consul consul nest-consul-loadbalance

Quick Start

Import Module

import { Module } from '@nestjs/common';
import { ConsulModule } from 'nest-consul';
import { LoadbalanceModule } from 'nest-consul-loadbalance';

@Module({
  imports: [
      ConsulModule.register({
        host: '127.0.0.1',
        port: 8500
      }),
      LoadbalanceModule.register({
        rules: [
            {service: 'test-service', ruleCls: 'RandomRule'},
            {service: 'user-service', ruleCls: '../rules/CustomRule'}
        ]
      })
  ],
})
export class ApplicationModule {}

If you use nest-boot module.

import { Module } from '@nestjs/common';
import { ConsulModule } from 'nest-consul';
import { LoadbalanceModule } from 'nest-consul-loadbalance';
import { BootModule } from 'nest-boot';
import { NEST_BOOT } from 'nest-common';

@Module({
  imports: [
      ConsulModule.register({dependencies: [NEST_BOOT]}),
      BootModule.register(__dirname, 'bootstrap.yml'),
      LoadbalanceModule.register({dependencies: [NEST_BOOT]})
  ],
})
export class ApplicationModule {}

Nest-boot config file

consul:
  host: localhost
  port: 8500
loadbalance:
  rules:
    - {service: 'test-service', ruleCls: 'RandomRule'}
    - {service: 'user-service', ruleCls: '../rules/CustomRule'}

Usage

import { Component } from '@nestjs/common';
import { InjectLoadbalancee, Loadbalance } from 'nest-consul-loadbalance';

@Component()
export class TestService {
  constructor(@InjectLoadbalancee() private readonly lb: Loadbalance) {}

  async chooseOneNode() {
      const node = this.lb.choose('user-service');
  }
}

Custom Loadbalance Rule

import { Rule, Loadbalancer } from 'nest-consul-loadbalance';

export class CustomRule implements Rule {
    private loadbalancer: Loadbalancer;
    
    init(loadbalancer: Loadbalancer) {
        this.loadbalancer = loadbalancer;
    }

    choose() {
        const servers = this.loadbalancer.servers;
        return servers[0];
    }
}

API

class LoadbalanceModule

static register(options): DynamicModule

Import nest consul loadbalance module.

field	type	description
options.dependencies	string[]	if you are using nest-boot module, please set NEST_BOOT
options.ruleCls	string \| class	lb rule，support：RandomRule, RoundRobinRule, WeightedResponseTimeRule or custom lb rule, use relative path
options.rules	RuleOption	one service use one rule, eg：[{service: '', ruleCls: ''}]