NestJS: present response content from URL on healthcheck - nestjs

Question

I'm trying to develop a healthcheck endpoint with NestJS (in which I have no experience). One of the dependencies I want to check is Twilio's SMS service. So far, the best URL I've found to gather this information is https://status.twilio.com/api/v2/status.json. The problem here is that I don't want to merely ping this address, but to gather it's JSON response and present some of the information it provides, namely these:
Is it possible, using (or not) the Terminus module? In the official docs I didn't find anything regarding this, only simpler examples using pingCheck / responseCheck: https://docs.nestjs.com/recipes/terminus

Answer 1

Yes, it is possible.
I have never used this, but HttpHealthIndicator has responseCheck method to check depends on the API response message. You can specify a callback function to analyze responses from the API. The callback function should return boolean represents the status of the API.
I couldn't find this in the documents, but you can see it here.

Answer 2

Although meanwhile the logic for this healthcheck has changed (and so this question became obsolete), this was the temporary solution I've found, before it happened (basically a regular endpoint using axios, as pointed out in one of the comments above):
Controller
import { Controller, Get } from '#nestjs/common';
import { TwilioStatusService } from './twilio-status.service';
#Controller('status')
export class TwilioStatusController {
constructor(private readonly twilioStatusService: TwilioStatusService) {}
#Get('twilio')
getTwilioStatus() {
const res = this.twilioStatusService.getTwilioStatus();
return res;
}
}
Service
import { HttpService } from '#nestjs/axios';
import { Injectable } from '#nestjs/common';
import { map } from 'rxjs/operators';
#Injectable()
export class TwilioStatusService {
constructor(private httpService: HttpService) {}
getTwilioStatus() {
return this.httpService
.get('https://status.twilio.com/api/v2/status.json')
.pipe(map((response) => response.data.status));
}
}
Of course this wasn't an optimal solution, since I had to do this endpoint + a separated one for checking MongoDB's availability (a regular NestJS healthcheck, using Terminus), the goal being an healthcheck that glued both endpoints together.

Answer 3

It is possible to merge in any property to the resulting object. You can see that in the TypeScript Interface
/**
* The result object of a health indicator
* #publicApi
*/
export declare type HealthIndicatorResult = {
/**
* The key of the health indicator which should be uniqe
*/
[key: string]: {
/**
* The status if the given health indicator was successful or not
*/
status: HealthIndicatorStatus;
/**
* Optional settings of the health indicator result
*/
[optionalKeys: string]: any;
};
};
And here is an example:
diagnostics/health/healthcheck.controller
import { Controller, Get } from '#nestjs/common'
import { ApiTags } from '#nestjs/swagger'
import { HttpService } from '#nestjs/axios'
import { HealthCheckService, HealthCheck, HealthIndicatorStatus, HealthCheckError } from '#nestjs/terminus'
#ApiTags('diagnostics')
#Controller('diagnostics/health')
export class HealthController {
constructor(
private health: HealthCheckService,
private httpService: HttpService,
) { }
#Get()
#HealthCheck()
check() {
return this.health.check([
() => this.httpService.get('http://localhost:9002/api/v1/diagnostics/health').toPromise().then(({ statusText, config: { url }, data }) => {
const status: HealthIndicatorStatus = statusText === 'OK' ? 'up' : 'down'
return { 'other-service': { status, url, data } }
}).catch(({ code, config: { url } }) => {
throw new HealthCheckError('Other service check failed', { 'other-service': { status: 'down', code, url } })
}),
])
}
}
diagnostics/diagnostics.module.ts
import { Module } from '#nestjs/common'
import { TerminusModule } from '#nestjs/terminus'
import { HttpModule } from '#nestjs/axios'
import { HealthController } from './health/health.controller'
#Module({
imports: [
HttpModule,
TerminusModule,
],
controllers: [HealthController],
})
export class DiagnosticsModule { }