The Fargateway Pattern

the-fargateway/README.md

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+# The Fargateway
+
+This is an example CDK stack to run a Fargate service behind an API Gateway. It uses CloudMap for service discovery and does not need a Load Balancer. It's based on this blog post - https://aws.amazon.com/blogs/architecture/field-notes-serverless-container-based-apis-with-amazon-ecs-and-amazon-api-gateway/
+
+![Architecture](img/arch.drawio.png)
+
+## When You Would Use This Pattern
+
+This patterns allows an Fargate service to leaverage the capabilities provided by API Gateway (e.g. import/export of OpenAPI defintions, throttling, authorization).
+
+An advantage compared to [load balanced Fargate service](https://docs.aws.amazon.com/cdk/api/latest/docs/aws-ecs-patterns-readme.html#application-load-balanced-services) are lower costs. In Api Gateway 1 million requests per month costs around $1 whereas an ALB costs around $16 per month.
+
+## How to test pattern
+
+After deployment you will have an api gateway where the nginx Fargate service is served.
+
+## Available Versions
+
+- [TypeScript](typescript/)

the-fargateway/typescript/.gitignore

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+*.js
+!jest.config.js
+*.d.ts
+node_modules
+
+# CDK asset staging directory
+.cdk.staging
+cdk.out
+
+# Parcel default cache directory
+.parcel-cache

the-fargateway/typescript/.npmignore

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+*.ts
+!*.d.ts
+
+# CDK asset staging directory
+.cdk.staging
+cdk.out

the-fargateway/typescript/README.md

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+# The Fargateway
+
+## Useful commands
+
+- `npm run build` compile typescript to js
+- `npm run watch` watch for changes and compile
+- `npm run test` perform the jest unit tests
+- `npm run deploy` deploy this stack to your default AWS account/region
+- `cdk diff` compare deployed stack with current state
+- `cdk synth` emits the synthesized CloudFormation template

the-fargateway/typescript/bin/the-fargateway.ts

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+#!/usr/bin/env node
+import 'source-map-support/register';
+import * as cdk from '@aws-cdk/core';
+import { TheFargatewayStack } from '../lib/the-fargateway-stack';
+
+const app = new cdk.App();
+new TheFargatewayStack(app, 'TheFargatewayStack', {
+    env: { region: "eu-west-1" }
+});

the-fargateway/typescript/cdk.json

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+{
+  "app": "npx ts-node bin/the-fargateway.ts",
+  "context": {
+    "@aws-cdk/core:enableStackNameDuplicates": "true",
+    "aws-cdk:enableDiffNoFail": "true"
+  }
+}

the-fargateway/typescript/jest.config.js

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+module.exports = {
+  roots: ['<rootDir>/test'],
+  testMatch: ['**/*.test.ts'],
+  transform: {
+    '^.+\\.tsx?$': 'ts-jest'
+  }
+};

the-fargateway/typescript/lib/the-fargateway-stack.ts

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+import * as apiv2 from '@aws-cdk/aws-apigatewayv2';
+import * as apiv2int from '@aws-cdk/aws-apigatewayv2-integrations';
+import * as ec2 from '@aws-cdk/aws-ec2';
+import * as ecs from '@aws-cdk/aws-ecs';
+import * as servicediscovery from '@aws-cdk/aws-servicediscovery';
+import * as cdk from '@aws-cdk/core';
+
+export class TheFargatewayStack extends cdk.Stack {
+  constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
+    super(scope, id, props);
+
+    // Fargate and CloudMap needs to be setup in a VPC
+    const vpc = new ec2.Vpc(this, 'Vpc', {
+      maxAzs: 2, // Default is all AZs in the region
+    });
+
+    // CloudMap Namespace
+    const namespace = new servicediscovery.PrivateDnsNamespace(this, 'Namespace', {
+      name: 'cdk.dev',
+      vpc,
+    });
+
+    // Fargate Service (a simple nginx container)
+    const taskDefinition = new ecs.TaskDefinition(this, 'taskdef', {
+      compatibility: ecs.Compatibility.FARGATE,
+      memoryMiB: '512',
+      cpu: '256',
+    });
+    const containerDef = taskDefinition.addContainer('nginx', {
+      image: ecs.RepositoryImage.fromRegistry('public.ecr.aws/nginx/nginx:latest'),
+      logging: ecs.LogDrivers.awsLogs({ streamPrefix: 'fargateway' }),
+      healthCheck: {
+        command: ['curl --fail http://localhost || exit 1'],
+      },
+    });
+    containerDef.addPortMappings({ containerPort: 80 });
+
+    const cluster = new ecs.Cluster(this, 'cluster', { vpc });
+    const fargateService = new ecs.FargateService(this, 'fargateway', {
+      taskDefinition,
+      cluster,
+      cloudMapOptions: {
+        cloudMapNamespace: namespace,
+        dnsRecordType: servicediscovery.DnsRecordType.SRV,
+        name: 'fargateway',
+      },
+    });
+
+    // Http Api Gateway with default integration (routes all traffic to the Fargate service)
+    const apiSecurityGroup = new ec2.SecurityGroup(this, 'api', { vpc });
+    const vpcLink = new apiv2.VpcLink(this, 'VpcLink', {
+      vpc,
+      securityGroups: [apiSecurityGroup],
+    });
+
+    const fargatePort = new ec2.Port({ protocol: ec2.Protocol.TCP, fromPort: 80, toPort: 80, stringRepresentation: 'API to Fargate' });
+    fargateService.connections.allowFrom(apiSecurityGroup, fargatePort);
+
+    const defaultIntegration = new apiv2int.HttpServiceDiscoveryIntegration({
+      vpcLink,
+      service: fargateService.cloudMapService!,
+    });
+
+    // Connect it to "api"
+    const api = new apiv2.HttpApi(this, 'fargateapi', {
+      defaultIntegration,
+    });
+
+    new cdk.CfnOutput(this, 'HTTP API Url', {
+      value: api.url ?? 'Something went wrong with the deploy'
+    });
+  }
+}