I am working with the AWS SDK using the KMS libary. I would like to use async and await instead of callbacks.
import AWS, { KMS } from "aws-sdk";
this.kms = new AWS.KMS();
const key = await this.kms.generateDataKey();
However this does not work, when wrapped in an async function.
How can i use async and await here?
If you are using aws-sdk with version > 2.x, you can tranform a aws.Request to a promise with chain .promise() function.
For your case:
try {
let key = await kms.generateDataKey().promise();
} catch (e) {
console.log(e);
}
the key is a KMS.Types.GenerateDataKeyResponse - the second param of callback(in callback style).
The e is a AWSError - The first param of callback func
note: await expression only allowed within an async function
key outside of the try statement?
key variable at first, outside of the try block. But, why?key elsewhere in the program. I did end up figuring out what I was trying to do in a different way, though.await requires a Promise. generateDataKey() returns a AWS.Request, not a Promise. AWS.Request are EventEmitters (more or less) but have a promise method that you can use.
import AWS, {
KMS
} from "aws-sdk";
(async function() {
const kms = new AWS.KMS();
const keyReq = kms.generateDataKey()
const key = await keyReq.promise();
// Or just:
// const key = await kms.generateDataKey().promise()
}());
As of 2021 I'd suggest to use AWS SDK for JavaScript v3. It's a rewrite of v2 with some great new features
sample code:
const { KMSClient, GenerateDataKeyCommand } = require('@aws-sdk/client-kms');
const generateDataKey = async () => {
const client = new KMSClient({ region: 'REGION' });
const command = new GenerateDataKeyCommand({ KeyId: 'KeyId' });
const response = await client.send(command);
return response;
};
AWS SDK for JavaScript v3 new features
awaitrequires a promise; that takes a callback.