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@chris-ramon
Forked from maxrabin/CountLinesAndLetters.js
Created March 7, 2019 01:08
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Example Lambda Function to process lines of text files when uploaded to S3
'use strict';
var AWS = require('aws-sdk');
var S3 = new AWS.S3();
var readline = require('readline');
exports.handler = function (event, context) {
//Get S3 file bucket and name
//Make sure to loop through event.Records, don't assume there is only 1 in production!!!
var bucket = event.Records[0].s3.bucket.name;
var key = event.Records[0].s3.object.key;
//Create read stream from S3
var s3ReadStream = S3.getObject({Bucket: bucket, Key: key}).createReadStream();
//handle stream errors.
//Pass the S3 read stream into the readline interface to break into lines
var readlineStream = readline.createInterface({input: s3ReadStream, terminal: false});
//handle stream errors
var totalLineCount = 0;
var totalCharCount = 0;
readlineStream.on('line', function (line) {
//Do whatever you need with the line
//In this example we are just counting the number of lines and characters
totalLineCount += 1;
totalCharCount += line.length;
});
readlineStream.on('close', function () {
//Do cleanup here such as persist resultant calculations.
//In this example I'll just print to the log the total number of lines:
console.log("In s3://" + bucket + "/" + key + " there are " + totalLineCount + " lines, " + totalCharCount + " chars.");
context.succeed();
});
};
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