Serverless lambda trigger read json file - node.js

Question

I have lambda (Node) which has trigger to fire when a new JSON file added to our S3 bucket. Here is my lambda code
module.exports.bookInfo = (event, context) => {
console.log('Events ', JSON.stringify(event));
event.Records.forEach((record) => {
const filename = record.s3.object.key;
const bucketname = record.s3.bucket.name;
let logMsg = [];
const s3File = `BucketName: [${bucketname}] FileName: [${filename}]`;
console.log(s3File)
logMsg.push(`Lambda execution started for ${s3File}, Trying to download file from S3`);
try {
s3.getObject({
Bucket: bucketname,
Key: filename
}, function(err, data) {
logMsg.push('Data is ', JSON.stringify(data.Body))
if (err) {
logMsg.push('Generate Error :', err);
console.log(logMsg)
return null;
}
logMsg.push(`File downloaded successfully. Processing started for ${s3File}`);
logMsg.push('Data is ', JSON.stringify(data.Body))
});
} catch (e) {console.log(e)}
});
}
When i run this, i don't get file content and i suspect that lambda finishes execution before file read operation complete. I tried with async await without success. What i am missing here ? I was able to read small file of 1 kb but when my file grows like 100 MB, it causes issue.
Thanks in advance

Answer 1

I was able to do it through async/await. Here is my code
module.exports.bookInfo = (event, context) => {
event.Records.forEach(async(record) => {
const filename = record.s3.object.key;
const bucketname = record.s3.bucket.name;
const s3File = `BucketName: [${bucketname}] FileName: [${filename}]`;
logMsg.push(`Lambda execution started for ${s3File}, Trying to download file from S3`);
let response = await s3.getObject({
Bucket: bucketname,
Key: filename
}).promise();
})
}