An opinionated Python implementation of a MQTT-SN Gateway
This MQTT-SN Gateway was created to collect meter data from Elvaco CMi6110 communication modules, and other Elvaco metering products that support sending meter data via MQTT-SN.
This is not a full MQTT-SN implementation and does not aim to be. In previous iterations we used RabbitMQ with the mqtt plugin as the MQTT broker. But in later releases we removed the need to run an MQTT Broker at all and there is only need for an AMQP Broker like RabbitMQ. We where using the MQTT/AMQP translation feature in RabbitMQ but realied that we might as well not use the MQTT part at all and send everything directly on AMQP.
The server uses Valkey as Client Store and Topic Store. This means each instance is not depending on any internal state and can be put behind a load balancer.
- CONNECT
- REGISTER
- PUBLISH
- PINGREQ
- DTLS encryption - This should be done in some form of reverse proxy setup and not in this application.
The server can be run like:
python mqtt_sn_gateway/main.py
Clone the repo and install locally using -e
pip install -e .
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.
--json-logs Outputs logs in JSON-format
--help Show this message and exit.
You can pull the latest docker-image and run via docker if needed.
docker pull quay.io/u9n/mqtt-sn-gatewayYou can use either an .env file or environment variables to set up the gateway.
- MQTTSN_HOST: str, Example 0.0.0.0
- MQTTSN_PORT: int, Port so serve the gateway. Ex 2883
- MQTTSN_USE_PORT_NUMBER_IN_CLIENT_STORE: bool. use port number in client store key
- MQTTSN_AMQP_CONNECTION_STRING: str, default: amqp://guest:guest@localhost:5672//
- MQTTSN_AMQP_PUBLISH_EXCHANGE: str, default: mqtt-sn
- MQTTSN_VALKEY_CONNECTION_STRING: str: default: valkey://localhost:6379/0
- MQTTSN_SENTRY_DSN: str: default=None
The following is not supported in .env file:
- MQTTSN_DEBUG: bool, enables debug logging
- MQTTSN_ENV_FILE: str, path to env file
- MQTTSN_NO_ENV_FILES: bool, discard all use of env files
- MQTTSN_JSON_LOGS: bool, outputs structured logs in json format
If you have a NAT between the devices and the MQTT-SN Gateway it might be that incoming UDP-messages have the same IP.
The NAT will use a certain port number to be able to map responses back to the device. We need to activate the setting
MQTTSN_USE_PORT_NUMBER_IN_CLIENT_STORE so that the key in the client store looks like client:{ip}:{port}.
It is also important that the timeout for port assignment is high enough for your use case so that the NAT does not
remove the mapping when there is no messages being sent. If the mapping is removed the next message will get a new port
and the client will not be found in the client store. Which will result in a DISCONNECT and the device have to reconnect
and register again in the gateway. This causes more traffic and will also drain the battery of the device more than
necessary if battery operated.
This software is not fully open source. It uses a source available, non-compete license which allows you or your company to use the program for your own use. Using it in a commercial offering to others is not allowed and you will need another license granted to you.
We at Utilitarian offer support contracts and 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.