WeightToS3

var AWS = require('aws-sdk');
var s3 = new AWS.S3();

exports.handler = (event, context, callback) => {
    
    // Your bucket name and key here. Note that it should be in the same region as your lambda.
    var bucket = "nutbrownweight"; // TODO REPLACE THIS!
    var key = "weight.txt";
    
    // Values passed in to the Lambda
    var weight = event.weight;
    var date = event.date;
    
    // Create params object for AWS sdk call to S3.
    var params = {
        Bucket : bucket,
        Key : key,
    }
    
    // Retrieve the object from S3.
    s3.getObject(params, function(err, data) {
      if (err) { 
          console.log(err, err.stack); 
      } else {
          // Parse the contents of the object.
          var response = JSON.parse(data.Body.toString('utf-8'));
          var toPush = {
              "weight": weight,
              "date": date
          }
          
          // Add the new record to the array.
          response.push(toPush);
          
          // Write it back to S3.
          putObjectToS3(bucket, key, response);
          callback(null, 'Success');
      }
    });
    
    
};


function putObjectToS3(bucket, key, data){
       
    var params = {
        Bucket : bucket,
        Key : key,
        Body : JSON.stringify(data)
    }
        
    s3.putObject(params, function(err, data) {
      if (err) {
          callback(err);
          throw err;
      }
    });
}