• Install latest NodeJS, AWS and SAM CLI version.

• On AWS console create an user, and a group. Attach administratives rights to that group (those permisions are needed for SAM deployment).

• Create a root folder and from the CLI init a sam project (in our case we will use nodejs10x).

sam init --runtime nodejs10.x

• Choose: 1 - AWS Quick Start Templates.

• Project name [sam-app]: sam-app (Choose the name of your preference, for this tutorial, let's keep it sam-app).

• Wait for the cloning template process.

• Once downloaded, open the template.yaml file and add a new Resource (Keep the indentation to avoid any issues). In our case let's create the ClockFunction. This will create a simple API Gateway with a GET method retrieving the current hour.

  ClockFunction:
    Type: AWS::Serverless::Function # More info about Function Resource: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#awsserverlessfunction
    Properties:
      CodeUri: clock/
      Handler: handler.clock
      Runtime: nodejs10.x
      Events:
        ClockApi:
          Type: Api
          Properties:
            Path: /clock
            Method: get

• On sam-app folder create the clock folder. Inside clock create a file called handler.js and paste the next code:

const moment = require('moment');
exports.clock = async(event) => {
    console.log('Clock function run!');

    const message = moment().format();

    const response = {
        statusCode: 200,
        body: JSON.stringify(message)
    };

    return response;
}

• Open a terminal and type: npm install --save moment . This will save the dependencies needed on handler.js.

• cd the the root folder sam-app.

• Start the building by typing sam build.

• Build a S3 bucket in order to save all the files from this tutorial, typing:

aws s3 --region us-west-2 mb s3://bucket-name-of-your-preference.

• Package all the files (I decided using package.yml name for convention, use whichever you want to ):

sam package --template-file template.yaml --output-template-file package.yml --s3-bucket bucket-name-of-your-preference.

• Deploy (check your location, ours is us-west-2, and for the stack-name we used just sam-app, chose whichever you want to):

sam deploy --region us-west-2 --capabilities CAPABILITY_IAM --template-file package.yml --stack-name sam-app

• Let's add the ConvertTimeFunction on the template.yaml

  ConvertTimeFunction:
    Type: AWS::Serverless::Function # More info about Function Resource: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#awsserverlessfunction
    Properties:
      CodeUri: convert-time/
      Handler: handler.ConvertTime
      Runtime: nodejs10.x
      Events:
        ConvertTimeAPI:
          Type: Api
          Properties:
            Path: /convert-time
            Method: get

• On sam-app folder create a new folder called convert-time.

• On convert-time create a file called handler.js.

• Paste the next code on handler.js:

const moment = require('moment-timezone');

exports.ConvertTime = async(event) => {
    console.log('Convert Time was executed');

    let tz = event.queryStringParameters && event.queryStringParameters.tz;

    let formattedDate = moment().format();

    if (tz !== null) {
        formattedDate = moment().tz(tz).format();
    } else {
        tz = "GMT 0";
    }

    const message = "The time in " + tz + " is " + formattedDate;

    const response = {
        statusCode: 200,
        body: JSON.stringify(message)
    };

    return response;
}

• Open a terminal on convert-time and save the dependencies needed for the handler

npm install --save convert-time

Go back to sam-app folder , rebuild and repackage the whole project and deploy:

sam build

sam package --template-file template.yaml --output-template-file package.yml --s3-bucket bucket-name-of-your-preference.

sam deploy --region us-west-2 --capabilities CAPABILITY_IAM --template-file package.yml --stack-name sam-app.

If all went go, you should see the updates on the lambdas and API gateways as well \0/ \0/ :) .

aws cloudformation delete-stack --stack-name sam-app