Writing data to Dynamodb from Serverless

index.js

'use strict';

const doc = require('dynamodb-doc');
const dynamo = new doc.DynamoDB();
const Q = require('kew');

module.exports.handler = (event, context, callback) => {

  function putItem() {
    const defer = Q.defer();
    const query = event.queryStringParameters;
    const params = {
      TableName: 'test',
      Item: {
        customerId: query.customerId,
        durationInHours: parseInt(query.durationInHours),
      }
    };

    dynamo.putItem(params, defer.makeNodeResolver());
    return defer.promise;
  }

  function response(data, statusCode) {
    const response = {
      statusCode: statusCode,
      body: JSON.stringify({
        data: data,
        input: event,
      }),
    };

    callback(null, response);
  }

  putItem()
    .then(data => response(data, 200))
    .fail(err => response(err, 500));
};

query_string.txt

customerId=abc&durationInHours=447

serverless.yml

service: aws-nodejs

provider:
  name: aws
  runtime: nodejs4.3
  stage: dev
  region: ap-southeast-2
  iamRoleStatements:
    - Effect: "Allow"
      Action:
        - dynamodb:GetItem
        - dynamodb:BatchGetItem
        - dynamodb:Query
        - dynamodb:PutItem
        - dynamodb:UpdateItem
        - dynamodb:DeleteItem
        - dynamodb:BatchWriteItem
      Resource: "arn:aws:dynamodb:ap-southeast-2:*:*"

functions:
  hello:
    handler: index.handler
    events:
      - http:
          path: index
          method: post

I was struggling with getting writes to Dynamodb to work through API gateway even though it was working fine through the Lambda console. The reason, it seems, was that the callback function was not being called and the parent function finished before the callback executed.

My solution here is to use promises as this ensures that the callback function is executed.

Still not sure if this pattern is the best way to go but putting this out there in case this is of any help to someone.

im struggling greatly with this. is there any chance you are available for some help????? thanks! twitter or here. my twitter handle is fullstack_dev88