Cannot save a file with a specific format name and extension in Bucket


Hello everyone! I'm using a lambda function that saves a log into a bucket but I'm having a problem trying to save these files with a specific format name and file extension.

This is my code:

**const createBucket = async (s3, bucket, path, data) => { const putObjectRequest = { // Adds a bucket and key to the body. Bucket: bucket, Key: path, Body: data, ContentType: 'text/plain', }; return s3 .putObject(putObjectRequest) .promise() .then(respo => { return respo; }) .catch(errs => { throw errs; }); } const saveFile = async (bucket, current, date, historyData) => {

  const logName = util.format('ekt-%s_%s000000.log', current.toLowerCase(), date);
  const savedData = await createBucket(

if (!savedData) {
    throw new Error(
      `The file hasn't been created: ${current}/${logName}`
  console.log(`The file has been created: ${current}/${logName}`);


I'm trying to save a file with this format and extension ekt-cp_20230112000000.log but at the end the file is created with this format and extension **ekt-cp_20230112.txt **

I have no clue whats going on!

asked a year ago204 views
1 Answer


I understand you would like to upload a file to s3 using the AWS NodeJS SDK. Below is example code

// Load the AWS SDK for Node.js
var AWS = require('aws-sdk');
// Set the region 
AWS.config.update({region: 'REGION'});

// Create S3 service object
var s3 = new AWS.S3({apiVersion: '2006-03-01'});

// call S3 to retrieve upload file to specified bucket
var uploadParams = {Bucket: process.argv[2], Key: '', Body: ''};
var file = process.argv[3];

// Configure the file stream and obtain the upload parameters
var fs = require('fs');
var fileStream = fs.createReadStream(file);
fileStream.on('error', function(err) {
  console.log('File Error', err);
uploadParams.Body = fileStream;
var path = require('path');
uploadParams.Key = path.basename(file);

// call S3 to retrieve upload file to specified bucket
s3.upload (uploadParams, function (err, data) {
  if (err) {
    console.log("Error", err);
  } if (data) {
    console.log("Upload Success", data.Location);

You would call the above code with the following command:

node s3_upload.js BUCKET_NAME FILE_NAME

Please note, you should use the upload API to upload files, and not the createBucket API call. I hope this helps.

answered a year ago
  • No, I'm not trying to upload a file. I'm creating a new file with data. The file is created correctly except the name and file extension that I'm defining in my code

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