# PintBroker 🍺
[](https://circleci.com/gh/jjcarstens/pint_broker)
[](https://hex.pm/packages/pint_broker)
A simple, pint-sized MQTT broker that can be used for testing and development
> **Warning**
>
> This is not indended for production use and makes no attempts for large
> connection scaling and handling. It is also not considered feature complete,
> but handles most simple use cases.
**Supported:**
* Simple, unencrypted TCP connections
* [MQTT v3.1.1](http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.pdf)
* QoS 0
* Connect, publish, subscribe, and unsubscribe
* Ping requests
* Rule forwarding (see below)
**Unsupported:**
* SSL connections
* QoS 1 and 2
* [MQTT v5](https://docs.oasis-open.org/mqtt/mqtt/v5.0/mqtt-v5.0.pdf)
## Rule forwarding
Many production setups will have a few topics with rules that forward
messages to a handler such as an SQS queue or central service. This allows
for scaling of many devices to communicate with a few nodes. For testing,
you can specify rules when starting the broker which will forward
`Tortoise311.Package.Publish` structs to a handler function or process in
order to mimic this rule forwarding behavior. See `PintBroker.add_rule/3` for
more information.
**Example:**
```elixir
iex> s = self()
iex> handler1 = fn pub -> send(s, pub) end
iex> PintBroker.start_link(rules: [{"my/+/test/topic", handler1}])
{:ok, #PID<0.226.0>}
# You can publish from the broker or another client
iex> PintBroker.publish("my/first/test/topic", "hello world")
iex> flush()
%Tortoise311.Package.Publish{
__META__: %Tortoise311.Package.Meta{opcode: 3, flags: 0},
identifier: nil,
topic: "my/first/test/topic",
payload: "hello world",
qos: 0,
dup: false,
retain: false
}
```
## Why _another_ broker?
There are many full-featured MQTT brokers out there, but they require a lot of
setup and configuration, maybe some dependencies, and tend to be overkill for
testing of MQTT interactions between client and servers. I wanted the simplest
possible broker which did not require a full ops team to implement a test
environment that clients could connect to and publish/subscribe to topics for
improved MQTT unit testing and local development of the whole system.
