mqtt-sn-gateway

An asyncio Python implementation of a MQTT-SN Gateway

About

We built this since we needed a nice way to interface MQTT-SN devices into our data stream. It is not feature complete as we wrote it quite quick but we hope to add onto it as our need grows. We used a transparent gateway before we built this and once we got over 1000 devices we got problems with the underlying I/O implementation. So this gateway is built as an aggregating gateway with multiple connections to the MQTT broker.

Supported features

CONNECT - In-memory store of clients
REGISTER - In-memory store of registered topics in clients
PUBLISH - Receive a PUBLISH and forward it to MQTT broker

Not supported - yet!

Gateway ADVERTISE
LAST WILL and TESTAMENT
QoS 2 and QoS-1
SUBSCRIBE
PINGREG/PINGRESP
Encapsulated messages
DTLS encryption

Future work

We would like a Redis-backed client and topic store. This would make it possible to run several instances of the gateway with shared and persistent state for handling higher loads and services outages.

Install

Requires Python 3.7 and higher (since we use asyncio and it is much nicer in 3.7+)

pip install mqtt-sn-gateway

Run via CLI

After installing via pip you can run the server via the command mqtt-sn-server

mqtt-sn-gateway --help

>
Usage: mqtt-sn-gateway [OPTIONS]

  Will assume there is a .env file in the root of the package. This is for
  simple development. To use .env files as in production use the --env-file
  arg to specify path. To make force the application to discard all .env files
  use the --no-env-files flag.

Options:
  --debug          Enable debug logging
  --env-file TEXT  Path to .env file
  --no-env-files   Discard all use of .env files.
  --help           Show this message and exit.

Run via Docker

You can pull the latest docker-image and run via docker if needed.

docker pull quay.io/u9n/mqtt-sn-gateway

Settings

You can use either an .env file or environment variables to set up the gateway.

HOST: str, Example 0.0.0.0
PORT: int, Port so serve the gateway. Ex 2883
BROKER_HOST: str, Broker host, Ex: test.mosquitto.com
BROKER_PORT: int, Borker port, Default=1883
BROKER_CONNECTIONS: int: How many connections the gatewat should have to the broker, default=10
BACK_PRESSURE_LIMIT: int: How many unhandled UDP-packets should be queued up before not receiving more traffic, Default=1000

Extend

It is possible to implement your own client and topic stores. Just supply the gateway an object the follows the correct Protocol.

class ClientStore(Protocol):
    def add_client(self, client: MqttSnClient) -> None:
        ...

    def get_client(self, remote_addr: Tuple[str, int]) -> Optional[MqttSnClient]:
        ...

    def delete_client(self, remote_addr: Tuple[str, int]) -> None:
        ...
    
    
class TopicStore(Protocol):
    def add_topic_for_client(self, client_id: bytes, topic_name: str) -> int:
        ...

    def get_topic_for_client(self, client_id: bytes, topic_id: int) -> Optional[str]:
        ...

Contribute

We appreciate all contributions. File a bug report or fix the issue yourself and submit a pull request.

Commercial support or custom development

We at Utilitarian can help your company with integrating the gateway to your systems. Contact us if you wish to speed up development or make sure your solution has long-term support.