hummingbird MQTT broker

This is a multi-threaded MQTT broker (framework) written in Haskell.

It is based on the Haskell MQTT library.

Batteries included

The package installs hummingbird which is already a full-fledged MQTT broker with configuration files, logging, authentication etc.

If this is not sufficient for your use case you might also consider to assemble your own broker (i.e. with a custom authentication mechanism).

Quick Start

Download a release and install it via

sudo dpkg -i hummingbird_w.x.y.z-1_amd64.deb

You now want to adapt /etc/hummingbird/config.yml to suit your needs. The broker comes with no configured users, so you might want to use the following file as a starting point: /usr/share/hummingbird/resources/principals/mqtt-default.yml and copy the new user file to /etc/hummingbird/principals/.

cp /usr/share/hummingbird/resources/principals/mqtt-default.yml /etc/hummingbird/principals/

To generate a bcrypt encrypted password salt+hash pair, you can use a subcommand of hummingbird

hummingbird pwhash

All *.yml files in principals and its subfolders will be read by the broker.

Every change in configuration or authentication needs a restart of this feature

sudo hummingbird cli --interactive=false --command="config reload"
sudo hummingbird cli --interactive=false --command="auth restart"

If you don't want to use sudo, the executing user has to be in the hummingbird group.

Customized brokers

The package exports modules which make it easy to compile a custom broker executable. Look into the hummingbird implemention for getting started!

Creating a self-signed certificate for client authentication

The following script creates a 2048 bit RSA keypair and a self-signed certificate to be used by the client for authentication.

The server only needs to know the public key. It will accept any certificate signed with the corresponding private key and doesn't use any other information from the certificate.

#!/bin/bash

set -e

openssl genrsa -out private.pem 2048
openssl rsa -in private.pem -outform PEM -pubout -out public.pem
openssl req -new -sha256 -key private.pem -out csr.csr -subj "/CN=$1"
openssl req -x509 -sha256 -days 3650 -key private.pem -in csr.csr -out certificate.pem
openssl x509 -text -in certificate.pem

Using a self-signed certificate with mosquitto_pub

mosquitto_pub  -h localhost -p 8883 -V mqttv311 \
  --cafile "resources/hummingbird_ca.crt" \
  --cert "resources/mqtt-default.crt" \
  --key "resources/mqtt-default.key" \
  -t "abc/def" \
  -m "asdasd"

If a username is not explicitly given, the broker will use the attribute Subject: CN = from the supplied certificate. An explicitly set username will override the one from the certificate.

License

Permission is hereby granted under the terms of the MIT license:

Copyright (c) 2016 Lars Petersen

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.