Question

如何防止abstract class RateMembershipType(...) : MembershipType(...), IRateOption object GOLD: RateMembershipType(...) object BRONZE: MembershipType(...) fun membershipSelected(membershipSelected: List<RateMembershipType>) = ...消息首先被记录？我想要Service running ... fn中的消息。而是先登录。当数据库未运行时，我希望testDBConnection消息保持记录状态，一旦数据库启动Looks like DB is not running，DB connection has been established消息就会跟随。我尝试了多种方法，但是无法提供正确的代码。感谢您的帮助。

index.js

Service running ...

db.js

import app from './config/express';
import config from './config/config';
import logger from './config/winston';
import { initDbConnection } from './server/db';

app.listen(config.port, () => {
  initDbConnection();
  logger.info(`Service running and listening on port ${config.port}`);
});

Answer 1

您可以为此使用异步/等待。

import app from './config/express';
import config from './config/config';
import logger from './config/winston';
import { initDbConnection } from './server/db';

app.listen(config.port, async () => {
  await initDbConnection();
  logger.info(`Service running and listening on port ${config.port}`);
});

db.js：

import knex from 'knex';
import config from '../config/config';
import logger from '../config/winston';

const { db } = config;
let pool, connected;

const testDBConnection = (client) => {
   return new Promise(resolve => {
   const intervalId = setInterval(async () => {
        try {
          await client.select(1);
          if (connected) {
              return;
          }
          connected = true;

          logger.info('DB connection has been established');
          clearInterval(intervalId);
          resolve('success');
        } catch (error) {
          logger.error('Looks like DB is not running');
        }
      }, 2000);
   });
};

export const initDbConnection = (mock) => {
  if (mock) {
    pool = knex({});
  } else {
    pool = knex({
      client: 'pg',
      version: '7.4.2',
      connection: db,
      debug: true
    });
    return testDBConnection(pool);
  }
};

export const getDb = () => pool;

这样，在解析initDbConnection之前，不会调用app.listen cb中的记录器。另一种方法是仅使用承诺then。

如何按我需要的顺序获取日志消息？

1 个答案: