使用 NestJs 和 Mysql 检查连接是否成功

Question

标题不言自明，我开始学习 NestJS，我想知道是否有可能，例如 console.log 或其他方式，知道与数据库的连接是否成功。

当我运行 npm run start:dev 时，一切都编译正常，但我仍然不确定我是否能够连接到数据库。

注意：我正在使用import { TypeOrmModule } from '@nestjs/typeorm/dist/typeorm.module';

编辑：如果在运行安装您的应用程序（在您的终端上）后出现此行

TypeOrmModule dependencies initialized

这意味着您已成功建立与数据库的连接

Answer 1

import { Connection, createConnection, getConnectionManager } from 'typeorm';

const connectionManager = getConnectionManager();

try {
      getConnection(connection.name);
    } catch (error) {
      await createConnection(connection);
    }

Answer 2

如果您的连接失败，您将在您的控制台中收到一个非常明确的错误：

[Nest] 1274   - 04/09/2021, 11:24:52 AM   [TypeOrmModule] Unable to connect to the database. Retrying (1)... +2042ms
Error: getaddrinfo ENOTFOUND localhast
    at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:66:26)

或

Unable to connect to the database. Retrying (2)... +3009ms
error: password authentication failed for user "mysql"
    at Parser.parseErrorMessage (nest/node_modules/pg-protocol/src/parser.ts:357:11)
    at Parser.handlePacket (nest/node_modules/pg-protocol/src/parser.ts:186:21)
    at Parser.parse (nest/node_modules/pg-protocol/src/parser.ts:101:30)
    at Socket.<anonymous> (nest/node_modules/pg-protocol/src/index.ts:7:48)
    at Socket.emit (events.js:315:20)
    at Socket.EventEmitter.emit (domain.js:483:12)
    at addChunk (_stream_readable.js:295:12)
    at readableAddChunk (_stream_readable.js:271:9)
    at Socket.Readable.push (_stream_readable.js:212:10)
    at TCP.onStreamRead (internal/stream_base_commons.js:186:23)

或

[Nest] 1412   - 04/09/2021, 11:32:36 AM   [TypeOrmModule] Unable to connect to the database. Retrying (2)... +3008ms
error: database "example" does not exist
    at Parser.parseErrorMessage (nest/node_modules/pg-protocol/src/parser.ts:357:11)
    at Parser.handlePacket (nest/node_modules/pg-protocol/src/parser.ts:186:21)
    at Parser.parse (nest/node_modules/pg-protocol/src/parser.ts:101:30)
    at Socket.<anonymous> (nest/node_modules/pg-protocol/src/index.ts:7:48)
    at Socket.emit (events.js:315:20)
    at Socket.EventEmitter.emit (domain.js:483:12)
    at addChunk (_stream_readable.js:295:12)
    at readableAddChunk (_stream_readable.js:271:9)
    at Socket.Readable.push (_stream_readable.js:212:10)
    at TCP.onStreamRead (internal/stream_base_commons.js:186:23)

没有消息表示成功

使用 NestJs 和 Mysql 检查连接是否成功

Check if connection was successful using NestJs and Mysql

mysql

connection

typeorm

nestjs