Sebastian Korfmann skorfmann

Stubbing Lambda Functions in your CDK Stack

Given you have a stack with one or more Lambda functions (e.g. as part of a Step Functions state machine), it can be pretty useful to stub long running parts with a known response.

This makes use of cdk Aspects, which allows modifying all or a filtered subsset of resources for a given scope (Stack, Construct).

In addition this leverages raw overrides to remove the original code of the Lambda function.

Please note, that the stub has to be in Python or NodeJS, since inlining code is only supported by those runtimes.

Private API Gateway with the AWS CDK

Lambda
Private Api Gateway
VPC Endpoint

NB: In order to access the Api Gateway through the public DNS of the VPC endpoint, a curl request has to have the api id as header. See also here

curl -i -H "x-apigw-api-id: " https://vpce-.execute-api..vpce.amazonaws.com/

EC2 Instance Connect meets AWS Session Manager via SSH

Both things have been introduced recently, and let you access even private ec2 instances

Without VPN
No open SSH port
Authentication / Authorization is fully delegated to IAM

# Assumes valid AWS Credentials in ENV

Distributed Key-Value Store

etcd

Raft protocol illustration

consul

A distributed Key value store is part of consul.io

Howto Reset etcd discovery

Every time my test cluster is going down, I was struggeling with etcd autodiscovery failing. This looks probably familiar to you:

The Problem

systemd[1]: Starting etcd...
systemd[1]: Started etcd.
etcd[3066]: [etcd] Apr  9 08:31:42.512 INFO      | Discovery via https://discovery.etcd.io using prefix /<TOKEN>.

	const AWS = require('aws-sdk')
	const appsync = require('aws-appsync');
	const gql = require('graphql-tag');
	require('cross-fetch/polyfill');

	exports.handler = async function(event) {
	const graphqlClient = new appsync.AWSAppSyncClient({
	url: process.env.APPSYNC_ENDPOINT_URL,
	region: process.env.AWS_REGION,
	auth: {


	import ecs = require('@aws-cdk/aws-ecs');
	import { DockerImageAsset } from '@aws-cdk/aws-ecr-assets';
	import path = require('path')

	export interface FooFargateProps {
	}

	export class FooFargate extends cdk.Construct {
	constructor(scope: cdk.Construct, id: string, props: FooFargateProps = {}) {

	require 'dnsimple'
	require 'platform-api'

	namespace :staging do
	desc "create subdomain DNS record for Heroku review app"
	task :publish_dns do
	heroku_app_name = ENV['HEROKU_APP_NAME']
	heroku_app_name =~ /.*(pr-\d+)/

	subdomain = $1

	shared_examples 'included before filter' do \|expected_filter, actions\|
	controller do
	skip_filter *_process_action_callbacks.map(&:filter).reject {\|filter\| filter == expected_filter }

	actions.each do \|action\|
	define_method(action) do
	render nothing: true
	end
	end
	end

	alias rs='rails server'
	alias rc='rails console'
	alias rg='rails generate'
	alias r='ruby'
	alias be='bundle exec'

	alias gst='git status' # Show the status
	alias gl='git pull --rebase' # Pull rebase
	alias gp='git push' # Push
	alias gu='git up' # Push