README

Table of Contents

• README
  • Table of Contents
  • Introduction
  • Quick Start
  • Listener Priority Reservations
  • Repo Layout
  • Testing
  • Default Opinions
  • Useful commands

Introduction

Buildkite pipeline: a-cloud-guru/infra-cdk-constructs

Quick Start

• Using a construct:

  1. Add this package to your projects package.json:

     yarn add @a-cloud-guru/cdk-constructs

  2. Inside your CDK application you can now import constructs

     import { RdsCluster, Engine } from '@a-cloud-guru/cdk-constructs';

• Adding a new construct:

  3. Create a file for the construct in ./lib/ with the naming convention <ConstructName>.ts. This will house the construct itself.
  4. Create tests for the construct in ./test/ with the naming convention <ConstructName>.test.ts. This will house jest tests for the construct.
  5. Update ./lib/index.ts to ensure that the new construct is being exported
  6. Update the package's version number in ./package.json

• Building a new package:

  3. Update ./package.json to ensure a new version is being published

  4. Run available tests yarn test and fix any breakages

  5. Use npm to create a release candidate: npm run build

  6. Use npm to publish the package (requires an NPM_TOKEN env var): npm publish

     # Build package
     npm run build
     # Publish release
     NPM_TOKEN=<x>

Listener Priority Reservations

Each use of the ContainerizedApp pattern requires a unique listener priority to use in the shared Application Load Balancer listener rule. Because of this requiremet a list of the currently reserved priorities is being tracked within confluence.

List of Application Listener Priority Reservations

When using this pattern in staging or production ensure to use/update this list.

Repo Layout

These are some of the major landmarks inside this repo:

./lib               -- Contains each of the constructs being made available
./lib/index.ts      -- Main entrypoint, only meant to export availble constructs
./test              -- Contains jest tests for IaC constructs
./examples          -- Contains usage examples of available constructs
./package.json      -- Dependency management and versioning

Testing

This project is currently being tested using the jest framework as described by the CDK's getting started guide on testing.

All tests can be found in the ./test/ directory and must end with a prefix of .test.js. Ideally each construct has an accompanied test suite with the same name as the construct in ./lib/

To run all available IaC tests use the following:

yarn test

Default Opinions

Almost all of the opinions expressed below can be overriden at synth time

• ALB:

  • Deletion protection enabled for "production" stage.
  • internetFacing: true

• ECR:

• ContainerizedApp:

  • Services are deployed to Fargate clusters
  • When desiredServiceCount is unspecified a default of 3 is used._
  • Container Image can be pinned to a specific commit using the COMMIT_HASH environment variable
  • LoadBalancer attached to services is publicly exposed
  • When registrationTimeout is unspecified a default of 300 is used
  • When circuitBreakerRollback is unspecified rollbacks are set to true
  • When containerInsights is unspecified containerInsights default to true.

• RdsCluster:

  • When no databaseEngine is specified PostgreSQL is the default
  • Storage is encrypted with a kms_key, if no kms_key_arn is provided one is created.
  • When no backupRetention period is specified the default is 35 days (cdk enforces Retention period must be between 1 and 35.)
  • When no backupWindow is specified a default of 08:00-09:00 is used (this is UTC and must be at least 30 minutes long).
  • Due to limited support (Only Legacy Aurora MySQL) no support for backtrackWindow is provided.
  • All parameter groups, by default, have max_connections set to 16000
  • When enablePerformanceInsights is unspecified it defaults to true
  • When deletionProtection is unspecified it defaults to true
  • Serverless:
    • backupWindow has no effect on Serverless clusters
    • Serverless does not support backtrackWindow.
    • Serverless does not support enablePerformanceInsights
  • Legacy MySQL:
    • Performance insights requires a InstanceClass higher than t3, we default to r3.large.
  • Legacy PostgreSQL
    • Aurora PostgreSQL does not support a backtrackWindow.

• RedisCluster:

  • One Redis cluster per application
  • When cacheNodeType is unspecified a size of cache.t2.small is used
  • When numCacheNodes is unspecified a size of 1 is used

• Security Groups:

  • Default security groups whitelist the following
    • Internal: 0.0.0.0/0:0 => 0.0.0.0/0:(3306|5432) (RDS)
    • Internal: 0.0.0.0/0:0 => 0.0.0.0/0:6379 (Redis)
    • Public: 0.0.0.0/0:0 => 0.0.0.0/0:(80) (Expose ALB to internet traffic)

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