add sample code for lambda function with fuction url (#136)

* add sample code for lambda function with fuction url

* add a makefile

Author: HarshCasper

lambda-function-urls/Makefile

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+export AWS_ACCESS_KEY_ID ?= test
+export AWS_SECRET_ACCESS_KEY ?= test
+export AWS_DEFAULT_REGION = us-east-1
+
+usage:       ## Show this help
+	@fgrep -h "##" $(MAKEFILE_LIST) | fgrep -v fgrep | sed -e 's/\\$$//' | sed -e 's/##//'
+
+install:     ## Install dependencies
+	@which awslocal || pip install awscli-local
+
+run:         ## Build, deploy, and invoke the Lambda function URL
+	npm i -g zip
+	zip function.zip index.js
+	awslocal lambda create-function \
+		--function-name localstack-lamba-url-example \
+		--runtime nodejs14.x \
+		--zip-file fileb://function.zip \
+		--handler index.handler \
+		--role cool-stacklifter
+
+	awslocal lambda create-function-url-config \
+		--function-name localstack-lamba-url-example \
+		--auth-type NONE
+
+start:
+	localstack start -d
+
+stop:
+	@echo
+	localstack stop
+
+ready:
+	@echo Waiting on the LocalStack container...
+	@localstack wait -t 30 && echo Localstack is ready to use! || (echo Gave up waiting on LocalStack, exiting. && exit 1)
+
+logs:
+	@localstack logs > logs.txt
+
+test-ci:
+	make start install ready run; return_code=`echo $$?`;\
+	make logs; make stop; exit $$return_code;
+	
+.PHONY: usage install start run stop ready logs test-ci

lambda-function-urls/README.md

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+# Creating a Lambda function with a function URL
+
+In this example, we will demonstrate how to create a Lambda function with a function URL. With the Function URL property, there is now a new way to call a Lambda Function via HTTP API call.
+
+## Prerequisites
+
+* LocalStack
+* Docker
+* `awslocal` CLI
+* Terraform
+
+## Starting up
+
+Start LocalStack via: 
+
+```sh
+localstack start -d
+```
+
+Push the following command to deploy the Lambda function:
+
+```sh
+awslocal lambda create-function \
+    --function-name localstack-lamba-url-example \
+    --runtime nodejs14.x \
+    --zip-file fileb://function.zip \
+    --handler index.handler \
+    --role cool-stacklifter
+```
+
+## Creating a Lambda function URL
+
+With the Function URL property, there is now a new way to call a Lambda Function via HTTP API call using the `create-function-url-config` command.
+
+```sh 
+awslocal lambda create-function-url-config \
+    --function-name localstack-lamba-url-example \
+    --auth-type NONE
+```
+
+You will retrieve a HTTP URL that you can use to invoke the Lambda function, in the form of `http://abcdefgh.lambda-url.us-east-1.localhost.localstack.cloud:4566`.
+
+You can now trigger the Lambda function by sending a HTTP POST request to the URL using `curl`:
+
+```sh
+curl -X POST \
+    'http://abcdefgh.lambda-url.us-east-1.localhost.localstack.cloud:4566/' \
+    -H 'Content-Type: application/json' \
+    -d '{"num1": "10", "num2": "10"}'
+```
+
+The following output would be retrieved:
+
+```sh 
+The product of 10 and 10 is 100% 
+```
+
+## Using Terraform
+
+You can use Terraform to automate the creation of Lambda function and to create a function URL. Run the following commands on your terminal to create the Lambda function and the function URL:
+
+```sh
+terraform init 
+terraform plan
+terraform apply --auto-approve
+```
+
+Since we are using LocalStack, no actual AWS resources will be created. Instead, LocalStack will create ephemeral development resources, which will automatically be cleaned once you stop LocalStack (using `localstack stop`).

lambda-function-urls/index.js

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+exports.handler = async (event) => {
+    let body = JSON.parse(event.body)
+    const product = body.num1 * body.num2;
+    const response = {
+        statusCode: 200,
+        body: "The product of " + body.num1 + " and " + body.num2 + " is " + product,
+    };
+    return response;
+};

lambda-function-urls/main.tf

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+data "aws_region" "current" {}
+
+resource "aws_lambda_function" "example_lambda" {
+  filename         = "function.zip"
+  function_name    = "localstack-lamba-url-example"
+  role             = "cool-stacklifter"
+  handler          = "index.handler"
+  source_code_hash = filebase64sha256("function.zip")
+  runtime          = "nodejs14.x"
+}
+
+resource "aws_lambda_function_url" "lambda_function_url" {
+  function_name      = aws_lambda_function.example_lambda.arn
+  authorization_type = "NONE"
+}
+
+output "function_url" {
+  description = "Function URL."
+  value       = aws_lambda_function_url.lambda_function_url.function_url
+}

lambda-function-urls/provider.tf

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+provider "aws" {
+  region                      = "us-east-1"
+  access_key                  = "fake"
+  secret_key                  = "fake"
+  skip_credentials_validation = true
+  skip_metadata_api_check     = true
+  skip_requesting_account_id  = true
+  s3_force_path_style         = true
+
+  endpoints {
+    apigateway      = "http://localhost:4566"
+    apigatewayv2    = "http://localhost:4566"
+    cloudformation  = "http://localhost:4566"
+    cloudwatch      = "http://localhost:4566"
+    cognitoidp      = "http://localhost:4566"
+    cognitosync     = "http://localhost:4566"
+    cognitoidentity = "http://localhost:4566"
+    dynamodb        = "http://localhost:4566"
+    ec2             = "http://localhost:4566"
+    es              = "http://localhost:4566"
+    elasticache     = "http://localhost:4566"
+    firehose        = "http://localhost:4566"
+    iam             = "http://localhost:4566"
+    kinesis         = "http://localhost:4566"
+    lambda          = "http://localhost:4566"
+    rds             = "http://localhost:4566"
+    redshift        = "http://localhost:4566"
+    route53         = "http://localhost:4566"
+    s3              = "http://localhost:4566"
+    secretsmanager  = "http://localhost:4566"
+    ses             = "http://localhost:4566"
+    sns             = "http://localhost:4566"
+    sqs             = "http://localhost:4566"
+    ssm             = "http://localhost:4566"
+    stepfunctions   = "http://localhost:4566"
+    sts             = "http://localhost:4566"
+  }
+
+  default_tags {
+    tags = {
+      Environment = "Local"
+      Service     = "LocalStack"
+    }
+  }
+}
+
+terraform {
+  # The configuration for this backend will be filled in by Terragrunt or via a backend.hcl file. See
+  # https://www.terraform.io/docs/backends/config.html#partial-configuration
+  #  backend "s3" {}
+
+  # Only allow this Terraform version. Note that if you upgrade to a newer version, Terraform won't allow you to use an
+  # older version, so when you upgrade, you should upgrade everyone on your team and your CI servers all at once.
+  required_version = "= 1.2.8"
+
+  required_providers {
+    aws = {
+      source  = "hashicorp/aws"
+      version = "~> 4.9.0"
+    }
+  }
+}