GetObject() not working after runtime update from Nodejs6.1 to Nodejs8.1

Question

I am using AWS Lambda with NodeJS runtime and I recently received a notification from AWS telling that they will stop maintaining lambdas running on node.js 6.10 runtime.

Basically, I am trying to get objects from S3 and create a stream from these objects in order to extract the data from a xlsx file.

This is the code I am trying to execute inside my lambda. This chunk of code worked on the node.js 6.10 runtime but does not work on the node.js 8.10 runtime.

function getWorkbookFromS3(s3Params): Promise<XLSX.WorkBook> {
    return new Promise((resolve, _reject) => {
        const buffers = [];
        S3Service.getObject(s3Params).createReadStream()
        .on('error', (error) => {
            console.log(error);
        }).on('data', (chunk) => {
            buffers.push(chunk);
        }).on('end', () => {
            const buffer = Buffer.concat(buffers);
            const workbook = XLSX.read(buffer, { type: 'buffer', cellDates: true });
            resolve(workbook);
        })
    });
}

Any clue on how to solve this?

Answer 1

The issue is related to the use of this function inside a lambda. I did not get any error, neither any result because once the lambda stopped its execution, the code inside the function getWorkbookFromS3(s3Params) could not get executed since it is a promise.

The way I called this function before was like this:

getWorkbookFromS3(s3Params).then((d) => {
    // do someting
});

But it didn't work. As a result, I had to add an await keyword in order to force the promise to be executed and prevent the lambda to stop its execution.

await getWorkbookFromS3(s3Params).then((d) => {
    // do someting
});