S3Client.completeMultipartUpload(bucketName, objectKey, uploadId, parts)

import crypto from 'k6/crypto';
import exec from 'k6/execution';

import { AWSConfig, S3Client } from 'https://jslib.k6.io/aws/0.11.0/s3.js';

const awsConfig = new AWSConfig({
    region: __ENV.AWS_REGION,
    accessKeyId: __ENV.AWS_ACCESS_KEY_ID,
    secretAccessKey: __ENV.AWS_SECRET_ACCESS_KEY,
    sessionToken: __ENV.AWS_SESSION_TOKEN,
});

const s3 = new S3Client(awsConfig);

const testBucketName = 'test-jslib-aws';
const testFileKey = 'multipart.txt';

export default async function () {
    // List the buckets the AWS authentication configuration
    // gives us access to.
    const buckets = await s3.listBuckets();

    // If our test bucket does not exist, abort the execution.
    if (buckets.filter((b) => b.name === testBucketName).length == 0) {
        exec.test.abort();
    }

    // Produce random bytes to upload of size ~12MB, that
    // we will upload in two 6MB parts. This is done as the
    // minimum part size supported by S3 is 5MB.
    const bigFile = crypto.randomBytes(12 * 1024 * 1024);

    // Initialize a multipart upload
    const multipartUpload = await s3.createMultipartUpload(testBucketName, testFileKey);

    // Upload the first part
    const firstPartData = bigFile.slice(0, 6 * 1024 * 1024);
    const firstPart = await s3.uploadPart(
        testBucketName,
        testFileKey,
        multipartUpload.uploadId,
        1,
        firstPartData
    );

    // Upload the second part
    const secondPartData = bigFile.slice(6 * 1024 * 1024, 12 * 1024 * 1024);
    const secondPart = await s3.uploadPart(
        testBucketName,
        testFileKey,
        multipartUpload.uploadId,
        2,
        secondPartData
    );

    // Complete the multipart upload
    await s3.completeMultipartUpload(testBucketName, testFileKey, multipartUpload.uploadId, [
        firstPart,
        secondPart,
    ]);

    // Let's redownload it verify it's correct, and delete it
    const obj = await s3.getObject(testBucketName, testFileKey);
    await s3.deleteObject(testBucketName, testFileKey);
}