How I learned AWS Lambda and SQS in 1 Afternoon.md

Lambda 1 (DB to SQS)

import boto3
from boto3.dynamodb.conditions import Key
from boto3.dynamodb.types import TypeDeserializer

import json

print('Loading function')
tableName = 'fizzbuzz'

dynamodb = boto3.resource('dynamodb')
table = dynamodb.Table(tableName)   

queueUrl='https://sqs.us-east-1.amazonaws.com/478193779867/FizzBuzzQ'
sqs = boto3.client('sqs')

deserializer = TypeDeserializer()


def lambda_handler(event, context):
    '''Demonstrates a simple HTTP endpoint using API Gateway. You have full
    access to the request and response payload, including headers and
    status code.

    To scan a DynamoDB table, make a GET request with the TableName as a
    query string parameter. To put, update, or delete an item, make a POST,
    PUT, or DELETE request respectively, passing in the payload to the
    DynamoDB API as a JSON body.
    '''
  
    output = table.get_item(
            Key={
                'key' : "fizzBuzzNTimes",
            }
        )
    n = int(str(output['Item']['number']))
    #n = deserializer.deserialize(output) # ['Item']['number']
    print(n)
    
    for i in range(1, n+1): # make output
        sqs.send_message(QueueUrl=queueUrl, MessageBody=str(i))
    
    return output

Lambda 2 (SQS to DB)

console.log('Loading function');

import { DynamoDBClient } from "@aws-sdk/client-dynamodb";
import {
  DynamoDBDocumentClient,
  ScanCommand,
  PutCommand,
  GetCommand,
  DeleteCommand,
} from "@aws-sdk/lib-dynamodb";

const client = new DynamoDBClient({});
const dynamo = DynamoDBDocumentClient.from(client);
const tableName = "fizzbuzz_output";

export const handler = async (event) => {
    
    let update = {}
    
    //console.log('Received event:', JSON.stringify(event, null, 2));
    for (const { messageId, body } of event.Records) {
        
        console.log('SQS message %s: %j', messageId, body);
        
        let num = body;
        let output = "";
        
        if (num === 0) {
            output = "0";
        }
        else if (num % 3 === 0 && num % 5 === 0) {
            output = "fizzbuzz";
        }
        else if (num % 3 === 0) {
            output = "fizz";
        }
        else if (num % 5 === 0) {
            output = "buzz";
        }
        else {
            output = num;
        }
        
        update[num] = output
        await dynamo.send(
            new PutCommand({
                TableName: tableName,
                Item: {
                    "key": num,
                    "value": output
                }
            })
        );
        
    } // end for loop
    
    console.log(update)

    return `Successfully processed ${event.Records.length} messages.`;
};