開発環境のアプリケーションは起動フェーズで非常に遅いです。何がそんなに時間を浪費しているのかを調べるために、さまざまな場所でデバッグログを設定しましたが、実際main.tsにはほとんど使用されていません。9分�� 輸入してもらうだけですapp.module!

ソース

import { performance } from 'perf_hooks';
const startTime = performance.now();

import { Log } from 'api/common/util/logger/log';
Log.log.info(`┌────────────────────────────────────────────────────────────┐`);
Log.log.info(`│    Starting: ${new Date().toISOString()}                      │`);
Log.log.info(`└────────────────────────────────────────────────────────────┘`);

// From here -------------------->
import { NestFactory } from '@nestjs/core';
import { ValidationPipe } from '@nestjs/common';
import 'reflect-metadata';
import { existsSync, mkdirSync, writeFile } from 'fs';
import * as express from 'express';
import * as bodyParser from 'body-parser';
import * as helmet from 'helmet';
import * as morgan from 'morgan';
import * as morganBody from 'morgan-body';
// <------ to here, imports fly in as expected.

// Theese take a bit longer, but not enormously
import { Config } from './api/common/config';
import { HttpExceptionFilter } from './api/common/filters/http-exception.filter';
import { LogService } from 'api/common/util/logger/log.service';

// This one takes up the most time on startup (several minutes)
import { AppModule } from './api/app.module';
Log.log.debug(` * imports done in ${(performance.now() - startTime).toFixed(3)}ms`);
Log.log.debug(` * Memory: ${readMem()}`);

function readMem() {
  const mem = process.memoryUsage();
  const convert = { Kb: n => (n / 1024), Mb: n => convert.Kb(n) / 1024 };
  const toHuman = (n, t) => `${convert[t](n).toFixed(2)}${t}`;
  return `Used ${toHuman(mem.heapUsed, 'Mb')} of ${toHuman(mem.heapTotal, 'Mb')} - RSS: ${toHuman(mem.rss, 'Mb')}`;
}

$ node dist/main.js
info: ┌──────────────────────────────────────────────────────────────────────────┐
info: │    Starting: 2019-01-29T13:06:13.751Z                                    │
info: │      Memory: Used 6.54Mb of 11.70Mb - RSS: 25.33Mb                       │
info: │     Runtime: js                                                          │
info: └──────────────────────────────────────────────────────────────────────────┘
debug:  * imports done in 6862.350ms
debug:  * Memory: Used 87.99Mb of 113.76Mb - RSS: 133.58Mb
info: Nest application successfully started
info: ┌──────────────────────────────────────────────────────────────────────────┐
info: │             Memory: Used 93.71Mb of 122.52Mb - RSS: 144.20Mb             │
info: │             Launch: 2019-01-29T13:06:25.377Z                             │
info: │      Time to start: 11991.049ms                                          │
info: │     Bootstrap time: 5124.189ms                                           │
info: └──────────────────────────────────────────────────────────────────────────┘

$ ts-node -r tsconfig-paths/register src/main.ts
info: ┌──────────────────────────────────────────────────────────────────────────┐
info: │    Starting: 2019-01-29T13:08:06.914Z                                    │
info: │      Memory: Used 157.76Mb of 193.62Mb - RSS: 209.77Mb                   │
info: │     Runtime: ts                                                          │
info: └──────────────────────────────────────────────────────────────────────────┘
debug:  * imports done in 471159.063ms
debug:  * Memory: Used 297.45Mb of 385.35Mb - RSS: 408.90Mb
info: Nest application successfully started
info: ┌──────────────────────────────────────────────────────────────────────────┐
info: │             Memory: Used 216.64Mb of 383.35Mb - RSS: 409.11Mb            │
info: │             Launch: 2019-01-29T13:16:05.521Z                             │
info: │      Time to start: 483228.325ms                                         │
info: │     Bootstrap time: 12042.239ms                                          │
info: └──────────────────────────────────────────────────────────────────────────┘