# AWS Fargate

This project contains a sample AWS Cloud Development Kit (AWS CDK) template for deploying an AWS Fargate service running on an Amazon Elastic Container Service (ECS) cluster fronted by an Application Load Balancer. This builds on the tutorial at [AWS CDK Creating an AWS Fargate service using the AWS CDK](https://docs.aws.amazon.com/cdk/latest/guide/ecs_example.html) by showing how to add a custom image without having to pre-push the image to Amazon Elastic Container Registry (ECR) or another container library. This makes use of the in-built `ecs.ContainerImage.fromAsset` method. The custom image used is a simple hello world Node Js application. This project also provides an example of how to pass an environment variable to the image. Note that the image can be changed to other images that suit your use case by changing the codes found in the `src` directory.

Learn more about this pattern at Serverless Land Patterns: https://serverlessland.com/patterns/cdk-fargate.

Important: this application uses various AWS services and there are costs associated with these services after the Free Tier usage - please see the [AWS Pricing page](https://aws.amazon.com/pricing/) for details. You are responsible for any AWS costs incurred. No warranty is implied in this example.

Warning: As of this writing, there are known issues with the images built on Apple's M1 chip, which is based on the ARM architecture. You might encounter the following error log on ECS `standard_init_linux.go:228: exec user process caused: exec format error fargate`. More details can be found at [Stackoverflow 'exec user process caused: exec format error' in AWS Fargate Service](https://stackoverflow.com/questions/67361936/exec-user-process-caused-exec-format-error-in-aws-fargate-service)

## Requirements

- [Create an AWS account](https://portal.aws.amazon.com/gp/aws/developer/registration/index.html) if you do not already have one and log in. The IAM user that you use must have sufficient permissions to make necessary AWS service calls and manage AWS resources.
- [AWS CLI](https://docs.aws.amazon.com/cli/latest/userguide/install-cliv2.html) installed and configured
- [Git Installed](https://git-scm.com/book/en/v2/Getting-Started-Installing-Git)
- [AWS CDK](https://docs.aws.amazon.com/cdk/latest/guide/cli.html) installed and configured

## Deployment Instructions

1. Create a new directory, navigate to that directory in a terminal and clone the GitHub repository:
   ```bash
   git clone https://github.com/aws-samples/serverless-patterns
   ```
2. Change directory to the pattern directory:
   ```bash
   cd serverless-patterns/fargate-cdk/cdk
   ```
3. Install dependencies:
   ```bash
   npm install
   ```
4. From the command line, configure AWS CDK:
   ```bash
   cdk bootstrap ACCOUNT-NUMBER/REGION # e.g.
   cdk bootstrap 1111111111/us-east-1
   cdk bootstrap --profile test 1111111111/us-east-1
   ```
5. From the command line, use AWS CDK to deploy the AWS resources for the pattern as specified in the `lib/cdk-stack.ts` file:
   ```bash
   cdk deploy
   ```
6. Note the outputs from the CDK deployment process. This contains the service endpoint that is used to access the hello world application.

## How it works

- The image is constructed directly from sources on disk when `cdk deploy` is executed
- The image is then automatically pushed to Amazon ECR
- The ECS cluster is then created
- Networking resources are then created
- Finally the Fargate Service and the Task Definitions are created. This also passes the environment variable to the image.

## Testing

Retrieve the Fargate Service endpoint from the `cdk deploy` output to view the `hello world Serverless Fargate` response from the browser.

## Cleanup

1. Delete the stack
   ```bash
   cdk destroy
   ```

2. Navigate to ECR in the AWS console and delete the container images created

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SPDX-License-Identifier: MIT-0