NestJS on Heroku always failing to bind port - heroku

Question

I am trying to deploy my NestJS REST API on Heroku but I always get the following error:
Web process failed to bind to $PORT within 60 seconds of launch
My configuration is pretty straight forward:
In my main.ts I start my server with:
await app.listen(process.env.PORT || AppModule.port);
I added a Procfile in the root directory of my project which contains:
web: npm run start:prod
My package.json files contains these scripts:
"build": "tsc -p tsconfig.build.json",
"prestart:prod": "rimraf dist && npm run build",
"start:prod": "node dist/main.js",
The process on Heroku builds succesfully, prints out these seamingly reassuring lines:
TypeOrmModule dependencies initialized
SharedModule dependencies initialized
AppModule dependencies initialized
But then immediately crashes with:
Error R10 (Boot timeout) -> Web process failed to bind to $PORT within 60 seconds of launch
I use .env configuration across my application but I removed all HOST and PORT variables (and code references), so I have no clue what could be the cause of this error.
Am I missing something?
EDIT
I am hereby sharing my app.module and main.ts files:
app.module.ts
#Module({
imports: [
SharedModule,
TypeOrmModule.forRootAsync({
imports: [SharedModule],
inject: [ConfigService],
useFactory: async (configService: ConfigService) => ({
type: 'postgres',
host: configService.getString('POSTGRES_HOST'),
port: configService.getNumber('POSTGRES_DB_PORT'),
username: configService.getString('POSTGRES_USER'),
password: configService.getString('POSTGRES_PASSWORD'),
database: configService.getString('POSTGRES_DB'),
entities: [__dirname + '/**/*.entity{.ts,.js}'],
} as PostgresConnectionOptions),
}),
UserModule,
],
controllers: [
AppController,
],
providers: [
AppService,
],
})
export class AppModule {
static port: number;
static isDev: boolean;
constructor(configurationService: ConfigService) {
console.log(process.env.PORT);
AppModule.port = configurationService.getNumber('PORT');
AppModule.isDev = configurationService.getBoolean('ISDEV');
}
}
My configuration.service.ts is a simple utility that reads from .env files:
import * as dotenv from 'dotenv';
import * as path from 'path';
#Injectable()
export class ConfigService {
constructor() {
const filePath = path.resolve('.env');
dotenv.config({
path: filePath,
});
}
getNumber(key: string): number | undefined {
return +process.env[key] as number | undefined;
}
getBoolean(key: string): boolean {
return process.env[key] === 'true';
}
getString(key: string): string | undefined {
return process.env[key];
}
}
And finally my main.ts file:
async function bootstrap() {
console.log(process.env.PORT);
const app = await NestFactory.create(AppModule);
app.enableCors();
app.useGlobalPipes(new ValidationPipe(), new TimeStampPipe());
app.use(json({ limit: '5mb' }));
app.setGlobalPrefix('api/v1');
await app.listen(process.env.PORT || AppModule.port);
}
bootstrap();
Could it be that my configuration.service.ts is interfering with heroku's env file?

Answer 1

If you are using fastify instead express as your platform, you need to define the host to 0.0.0.0 explicitly like this :
const port = process.env.PORT || AppModule.port;
const host = '0.0.0.0';
await app.listen(port, host);
This problem is caused by the fastify library. See the related discussion here: Fastify with Heroku.

Answer 2

Just as a summary, be careful on the database connection timeout that could lead to a global timeout of the heroku bootstrap as describe above