如何使用 Serverless Framework 管理 Lambda 内 Aurora Serverless 数据 api 的 typeORM 连接

Question

我在用着：

• Aurora 无服务器数据 API (Postgres)
• TypeORM 与typeorm-aurora-data-api-driver
• 具有无服务器框架的 AWS Lambda（TypeScript、WebPack）

我正在连接到数据库，就像 github 中描述的那样，

const connection = await createConnection({
      type: 'aurora-data-api-pg',
      database: 'test-db',
      secretArn: 'arn:aws:secretsmanager:eu-west-1:537011205135:secret:xxxxxx/xxxxxx/xxxxxx',
      resourceArn: 'arn:aws:rds:eu-west-1:xxxxx:xxxxxx:xxxxxx',
      region: 'eu-west-1'
    })

这就是我在 Lambda 函数中使用它的方式

export const testConfiguration: APIGatewayProxyHandler = async (event, _context) => {
  let response;
  try {
    const connectionOptions: ConnectionOptions = await getConnectionOptions();
    const connection = await createConnection({
      ...connectionOptions,
      entities,
    });
    const userRepository = connection.getRepository(User);
    const users = await userRepository.find();

    response = {
      statusCode: 200,
      body: JSON.stringify({ users }),
    };
  } catch (e) {
    response = {
      statusCode: 500,
      body: JSON.stringify({ error: 'server side error' }),
    };
  }
  return response;
};

当我第一次执行时，效果很好。

但第二次和下一次我收到错误

AlreadyHasActiveConnectionError: Cannot create a new connection named "default", because connection with such name already exist and it now has an active connection session.

那么，管理此连接的正确方法是什么？是否应该以某种方式重用它？

我找到了一些简单 RDS 的解决方案，但 Aurora Serverless Data API的重点是您不必管理连接

Answer 1

当您尝试建立连接时，您需要检查是否已经存在可以使用的连接。这是我Database用来处理连接的类

export default class Database {
  private connectionManager: ConnectionManager;

  constructor() {
    this.connectionManager = getConnectionManager();
  }

  async getConnection(): Promise<Connection> {
    const CONNECTION_NAME = 'default';

    let connection: Connection;

    if (this.connectionManager.has(CONNECTION_NAME)) {
      logMessage(`Database.getConnection()-using existing connection::: ${CONNECTION_NAME}`);
      connection = await this.connectionManager.get(CONNECTION_NAME);

      if (!connection.isConnected) {
        connection = await connection.connect();
      }
    } else {
      logMessage('Database.getConnection()-creating connection ...');
      logMessage(`DB host::: ${process.env.DB_HOST}`);

      const connectionOptions: ConnectionOptions = {
        name: CONNECTION_NAME,
        type: 'postgres',
        port: 5432,
        logger: 'advanced-console',
        logging: ['error'],
        host: process.env.DB_HOST,
        username: process.env.DB_USERNAME,
        database: process.env.DB_DATABASE,
        password: process.env.DB_PASSWORD,
        namingStrategy: new SnakeNamingStrategy(),
        entities: Object.keys(entities).map((module) => entities[module]),
      };

      connection = await createConnection(connectionOptions);
    }

    return connection;
  }
}