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# Haproxy configuration for SSL request passthrough to different backend based on SNI read from Handshaking stage
# The Loadbalance will not decode the encrpted data but transparently transfer to the backend server in Private subnet.
# With such configuration, you can install multiply services with its own SSL certificate in backend in different EC2 instance, but only explosure to public internet with one Loadbalance IP. There is no need to install SSL certificate in Loadbalancer level.

# Ref:
#	How to support wildcard sni: https://stackoverflow.com/questions/24839318/haproxy-reverse-proxy-sni-wildcard
#	https://www.haproxy.com/blog/enhanced-ssl-load-balancing-with-server-name-indication-sni-tls-extension/
#	https://stuff-things.net/2016/11/30/haproxy-sni/

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Table of Contents

• set -e, -u, -x, -o pipefail
• set -e
• set -x
• set -u
• set -o pipefail
• Setting IFS
• Original Reference

set -e, -u, -x, -o pipefail

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Scaling your API with rate limiters

The following are examples of the four types rate limiters discussed in the accompanying blog post. In the examples below I've used pseudocode-like Ruby, so if you're unfamiliar with Ruby you should be able to easily translate this approach to other languages. Complete examples in Ruby are also provided later in this gist.

In most cases you'll want all these examples to be classes, but I've used simple functions here to keep the code samples brief.

Request rate limiter

This uses a basic token bucket algorithm and relies on the fact that Redis scripts execute atomically. No other operations can run between fetching the count and writing the new count.

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update global_variables set
-- UserDataMonitor 
variable_value="DBMONUSER" 
where variable_name='mysql-monitor_username';

update global_variables set
-- PasswordDataMonitor 
variable_value="DBMONPASS" 
where variable_name='mysql-monitor_password';

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Install StatsD on Debian Stretch

Install nodejs:

# curl -sL https://deb.nodesource.com/setup_12.x | bash -
# apt install -y nodejs

Install build dependencies:

$ sudo apt install git debhelper devscripts dh-systemd

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#!/bin/bash

# Copyright © 2017 Google Inc.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software

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Problem

Installing mysql2 gem errors on MacOS Mojave.

Solution

Make sure openssl is installed on Mac via Homebrew.

brew install openssl

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require 'cgi'
require 'json'
require 'active_support'

def verify_and_decrypt_session_cookie(cookie, secret_key_base)
  cookie = CGI::unescape(cookie)
  salt         = 'encrypted cookie'
  signed_salt  = 'signed encrypted cookie'
  key_generator = ActiveSupport::KeyGenerator.new(secret_key_base, iterations: 1000)
  secret = key_generator.generate_key(salt)[0, ActiveSupport::MessageEncryptor.key_len]

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Setup redis-cli on AWS EC2

SSH into your EC2 instance. Run the following:

$ sudo yum install gcc This may return an "already installed" message. That's OK.

$ wget http://download.redis.io/redis-stable.tar.gz && tar xvzf redis-stable.tar.gz && cd redis-stable && make

See: http://docs.aws.amazon.com/AmazonElastiCache/latest/UserGuide/GettingStarted.ConnectToCacheNode.Redis.html

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JQ to filter JSON by value

Syntax: cat <filename> | jq -c '.[] | select( .<key> | contains("<value>"))'

Example: To get json record having _id equal 611

cat my.json | jq -c '.[] | select( ._id | contains(611))'

Remember: if JSON value has no double quotes (eg. for numeric) to do not supply in filter i.e. in contains(611)