aws-sdk-js E2 createVPC 在等待添加 promise 时执行了两次

Question

    ec2
      .createVpc(params, function (err, data) {
        if (err) {
          console.log(err, err.stack);
          // an error occurred
        } else {
          logger.log.info(
            `Deployment VPC ${deployment.name} has been created.`
          );
          db.saveData(data, deployment.name);

          return data;
        }
      })
      .promise()

I was trying to run this code above, which is the most simplest resource in the docs. But when I added .promise() the create operation was triggered twice. When I remove it, it creates only one instance of VPC. But I need to access the information about the created resource in order to save it to the database.

Answer 1

I would guess that this happens because you mix two ways of triggering a request - providing a callback and calling a promise. If you want to use promises, you should process the returned data in then() (or use await ).

Example with then() :

ec2.createVpc(params).promise().then((data) => {
    logger.log.info(
       `Deployment VPC ${deployment.name} has been created.`
    );
    db.saveData(data, deployment.name);
    return data;
}, (err) => {
    console.log(err, err.stack);
})