Error when creating items AWS Lambda to DynamoDB with python

Question

I am trying to create a new Item in my table and every time I run the following code:

from __future__ import print_function
from decimal import *
import boto3
import json

def my_handler(event, context):
    marker = event['m']
    latitude = Decimal(event['lat']) 
    longitude = Decimal(event['lon'])
    tableminfo = 'minfo'
    client = boto3.client('dynamodb')

    client.put_item(
      TableName = tableminfo, Item = {
      'marker':{'N' : marker},
      'latitude':{'N' : latitude},
      'longitude':{'N' : longitude},
        }
    )

    success = "Success"     
    return {'success' : success}

with the following test parameters in Lambda

{
  "m": 1,
  "lat": 52.489505,
  "lon": 13.389687
}

I receive an error on the following lines: 17, "my_handler", "'longitude':{'N' : longitude},"

Answer 1

you must update values as string:

client.put_item(
      TableName = tableminfo, Item = {
      'marker':{'N' : str(marker)},
      'latitude':{'N' : str(latitude)},
      'longitude':{'N' : str(longitude)},
        }
    )

Answer 2

You can also use the higher-level resource interface that boto3 provides for DynamoDB. It handles a lot of the low-level details for you. Here's a version of your code using the resource layer.

Assuming your event looks like this:

{
  "m": 1,
  "lat": 52.489505,
  "lon": 13.389687
}

This code would persist the data to DynamoDB

import boto3

client = boto3.resource('dynamodb')
table = client.Table('minfo')

def my_handler(event, context):
    item = {
        'marker': event['m'],
        'latitude': event['lat'],
        'longitude': event['lon']}
    table.put_item(Item=item)   
    return {'success' : "Success"}

Creating the client and Table at the module level is more efficient because then you won't pay the price of creating them every time your Lambda function is called.