Added HAProxy cookbook

cookbook/recipe-haproxy/Dockerfile

@@ -0,0 +1,33 @@
+
+FROM ruby:3.2-alpine
+
+# This are the defaults if not overruled by --env VAR="" from docker run
+ENV HAPROXY_GW_PORTS="2525"
+ENV HAPROXY_GW_HOSTS="*"
+ENV HAPROXY_GW_MAX_PROCESSINGS="4"
+
+# Do not show extended debug log
+ENV HAPROXY_GW_DEBUG="debug"
+
+######################################################
+
+RUN apk update
+RUN apk upgrade --force
+RUN apk add alpine-sdk
+RUN apk add git
+RUN apk add openssl-dev
+
+ADD ./src/ /app/
+
+WORKDIR /app
+
+RUN ruby -v
+RUN gem update --system | head -n 8
+RUN bundle config set --local path '.ruby/gems'
+RUN export GEMRC="Gemrc.yml"
+RUN bundle install --jobs 32 --retry 3
+
+RUN chown -R root:root /app
+
+# Spin up service
+CMD ["bundle", "exec", "ruby", "service/midi-smtp-server-recipe-haproxy-mta.rb"]

cookbook/recipe-haproxy/README.md

@@ -0,0 +1,54 @@
+<p align="center" style="margin-bottom: 2em">
+ <img src="https://cdn.haproxy.com/assets/our_logos/haproxy-icon.svg" alt="HAProxy Logo" width="40%"/>
+</p>
+
+<br>
+
+## HAProxy Cookbook
+
+This is a cookbook recipe that makes use of [midi-smtp-server](https://github.com/4commerce-technologies-AG/midi-smtp-server) and
+[HAProxy](http://www.haproxy.org/) to load-balance incoming connections across multiple smtp backends.
+In addition there is a [Docker](https://www.docker.io/) template to build and run a full service.
+
+Note: `haproxy` instances that are proxying smtp connections from upstream proxies, should be configured with
+`accept-proxy` directive. take a look at the master and chain configurations in the [data](./data) folder.
+### Settings
+
+##### PROXY_GW_PORTS="2525"
+
+The port(s) the mail gateway will listen on.
+
+##### PROXY_GW_HOSTS="127.0.0.1"
+
+The ip-address(es) the mail gateway will listen on.
+
+##### PROXY_GW_MAX_PROCESSINGS="4"
+
+The number of simultaneous processed connections.
+
+##### PROXY_GW_DEBUG="debug"
+
+Show some extended debug information.
+
+<br>
+
+### Usage with Docker Compose
+
+Bring up the `haproxy-mater`, `haproxy-chain` and `smtp` services with:
+```sh
+docker compose up --build
+```
+
+Send test email using `haproxy-master`:
+```sh
+curl -v --url 'smtp://localhost:5555' -k --mail-from [email protected] --mail-rcpt [email protected] -F '='
+```
+
+Send test email directly to `smtp` service:
+```sh
+curl -v --url 'smtp://localhost:2525' -k --mail-from [email protected] --mail-rcpt [email protected] -F '='
+```
+
+### Author & Credits
+
+Author: [Iuri G.](https://github.com/iuri-gg)

cookbook/recipe-haproxy/data/proxy-chain/haproxy.cfg

@@ -0,0 +1,20 @@
+global
+ log stdout local0 info
+ maxconn 4000
+
+defaults
+ log global
+ mode tcp
+ option tcplog
+ option dontlognull
+ retries 3
+ timeout client 5s
+ timeout server 5s
+
+frontend smtp_ft
+ bind :4444 accept-proxy
+ default_backend smtp_bk
+
+backend smtp_bk
+ timeout connect 5s
+ server my-smtp midi-smtp:2525 send-proxy

cookbook/recipe-haproxy/data/proxy-master/haproxy.cfg

@@ -0,0 +1,20 @@
+global
+ log stdout local0 info
+ maxconn 4000
+
+defaults
+ log global
+ mode tcp
+ option tcplog
+ option dontlognull
+ retries 3
+ timeout client 5s
+ timeout server 5s
+
+frontend smtp_chain_ft
+ bind :5555
+ default_backend smtp_chain_bk
+
+backend smtp_chain_bk
+ timeout connect 5s
+ server chain-smtp proxy-chain:4444 send-proxy

cookbook/recipe-haproxy/docker-compose.yml

@@ -0,0 +1,22 @@
+---
+services:
+ proxy-master:
+ image: haproxy:lts
+ user: root
+ volumes:
+ - ./data/proxy-master:/usr/local/etc/haproxy:ro
+ ports:
+ - "5555:5555"
+ proxy-chain:
+ image: haproxy:lts
+ user: root
+ volumes:
+ - ./data/proxy-chain:/usr/local/etc/haproxy:ro
+ ports:
+ - "4444:4444"
+ midi-smtp:
+ build:
+ context: ./
+ dockerfile: ./Dockerfile
+ ports:
+ - "2525:2525"

cookbook/recipe-haproxy/src/Gemfile

@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+source 'https://rubygems.org'
+
+gem 'midi-smtp-server', '>=3.2.1'

cookbook/recipe-haproxy/src/Gemrc.yml

@@ -0,0 +1,20 @@
+---
+# sometimes update from remotes on docker will hang on IPv6
+ipv4_fallback_enabled: true
+
+# Self explanatory :-)
+benchmark: false
+
+# Verbosity of the gem command. false, true, and :really are the levels
+verbose: false
+
+# Enable/disable automatic updating of repository metadata
+update_sources: true
+
+# Print backtrace when RubyGems encounters an error
+backtrace: true
+
+# <gem_command>: A string containing arguments for the specified gem command
+# -N, --no-document - Disable documentation generation
+# --[no-]suggestions - Suggest alternates when gems are not found
+gem: --no-document --no-suggestions

cookbook/recipe-haproxy/src/service/midi-smtp-server-recipe-haproxy-mta.rb

@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+require 'midi-smtp-server'
+
+# Server class
+class MySmtpGw < MidiSmtpServer::Smtpd
+
+ # get each message after DATA <message> .
+ def on_message_data_event(ctx)
+ # Output for debug
+ logger.debug("mail received at: [#{ctx[:server][:local_ip]}:#{ctx[:server][:local_port]}], proxy #{ctx[:server][:proxy] || 'none'}, from: [#{ctx[:envelope][:from]}] for recipient(s): [#{ctx[:envelope][:to]}]...")
+ end
+
+end
+
+# flush the log output immediately after each write operation
+$stdout.sync = true
+
+# Create a new server instance for listening
+# If no ENV settings use default interfaces 127.0.0.1:2525
+# Attention: 127.0.0.1 is not accessible in Docker container even when ports are exposed
+server = MySmtpGw.new(
+ ports: ENV.fetch('HAPROXY_GW_PORTS', MidiSmtpServer::DEFAULT_SMTPD_PORT),
+ hosts: ENV.fetch('HAPROXY_GW_HOSTS', MidiSmtpServer::DEFAULT_SMTPD_HOST),
+ max_processings: ENV.fetch('HAPROXY_GW_MAX_PROCESSINGS', '').to_s.empty? ? MidiSmtpServer::DEFAULT_SMTPD_MAX_PROCESSINGS : ENV.fetch('HAPROXY_GW_MAX_PROCESSINGS').to_i,
+ proxy_extension: true,
+ auth_mode: :AUTH_OPTIONAL,
+ tls_mode: :TLS_FORBIDDEN,
+ logger_severity: ENV.fetch('HAPROXY_GW_DEBUG', '').to_s.empty? ? Logger::INFO : Logger::DEBUG
+)
+
+# save flag for Ctrl-C pressed
+flag_status_ctrl_c_pressed = false
+
+# try to gracefully shutdown on Ctrl-C
+trap('INT') do
+ # print an empty line right after ^C
+ puts
+ # notify flag about Ctrl-C was pressed
+ flag_status_ctrl_c_pressed = true
+ # signal exit to app
+ exit 0
+end
+
+# Output for debug
+server.logger.info("Starting MySmtpGw [#{MidiSmtpServer::VERSION::STRING}|#{MidiSmtpServer::VERSION::DATE}] ...")
+
+# setup exit code
+at_exit do
+ # check to shutdown connection
+ if server
+ # Output for debug
+ server.logger.info('Ctrl-C interrupted, exit now...') if flag_status_ctrl_c_pressed
+ # info about shutdown
+ server.logger.info('Shutdown MySmtpGw...')
+ # stop all threads and connections gracefully
+ server.stop
+ end
+ # Output for debug
+ server.logger.info('MySmtpGw down!')
+end
+
+# Start the server
+server.start
+
+# Run on server forever
+server.join

mkdocs.yml

@@ -26,6 +26,7 @@ nav:
  - Cookbook:
  - Recipes: cookbook.md
  - Slack MTA: cookbook_recipe_slack_mta.md
+ - HAProxy load-balancing: cookbook_recipe_haproxy_mta.md
  - Support: support.md
  - Appendix:
  - Security: appendix_security.md

mkdocs/cookbook_recipe_haproxy_mta.md

@@ -0,0 +1,14 @@
+<h2>HAProxy load-balancing</h2>
+
+HAProxy load-balancing recipe shows how to use one or more HAProxy instances to load-balance incoming connections
+across multiple smtp backends.
+
+The recipe comes with simple SMTP server that can be used as a backend for HAProxy. The server is based
+on `midi-smtp-server`
+and prints the proxy and sender information to the console.
+
+Take a look at the example recipe in
+the [cookbook/recipe-haproxy](https://github.com/4commerce-technologies-AG/midi-smtp-server/tree/master/cookbook/recipe-haproxy)
+folder. Have fun to use and extend this recipe for your own ideas and needs.
+
+<br>