MQTT2ETCD

Bridge between MQTT and ETCD, that can:

• PUT on ETCD by publishing on MQTT
• Watch ETCD keys and Publish changes on MQTT

Requirements

• Python >= 3.6
• Packages listed on requirements.txt
• Docker recommended for deployment

Changelog

• 0.1.3 - add tests
• 0.1.2 - add logging
• 0.1.1 - add settings to customize MQTT topics
• 0.0.1 - initial version (base functional code, supporting MQTT2ETCD & ETCD2MQTT)

Settings

Settings can be defined through environment variables or using a .env file (located within the __main__.py file).

ETCD Settings

• MQTT2ETCD_HOST: ETCD server host (default: 127.0.0.1)
• MQTT2ETCD_PORT: ETCD server port (default: 2379)
• MQTT2ETCD_LISTEN_PREFIX: ETCD key prefix to watch (default=undefined; if undefined, will not watch)
• MQTT2ETCD_LISTEN_ALL: if 1, watch ALL ETCD keys (default=0; if 1 will override the LISTEN_PREFIX setting)
• MQTT2ETCD_PREV_KV: if 1, publish watched ETCD keys on startup (default=0)

MQTT Settings

• MQTT2ETCD_BROKER: MQTT broker host (default: 127.0.0.1)
• MQTT2ETCD_BROKER_PORT: MQTT broker port (default: 1883)
• MQTT2ETCD_CLIENT_ID: MQTT client ID (default: MQTT2ETCD-{uuid1})
• MQTT2ETCD_RETAIN: if 1, publish watched ETCD keys MQTT messages with Retain flag (default=0)
• MQTT2ETCD_TOPIC_BASE: Base level topic (default: mqtt2etcd)
• MQTT2ETCD_TOPIC_PUT: Context level for PUT (publish) keys (default: put)
• MQTT2ETCD_TOPIC_WATCH: Context level where watched keys get published (default: stat)
• MQTT2ETCD_TOPIC_STATUS: Context level where MQTT2ETCD service status messages get published (default: status)
• MQTT2ETCD_PAYLOAD_ONLINE: Payload to send on the Status topic when the service connects to MQTT (default: Online)
• MQTT2ETCD_PAYLOAD_OFFLINE: Payload to send on the Status topic when the service goes offline, as LWT (default: Offline)

Misc System Settings

• MQTT2ETCD_LOG_LEVEL: Log level for the logger (default: INFO)

MQTT Topics

Topics for ETCD keys are split in 3 levels (split by /):

1. Base level (default: mqtt2etcd)
2. Order/context level (default: put, stat)
3. ETCD key (it can contain multiple /, but shall not contain # nor +)

Having the order/context level at the end would be (personally) prefered, but would cause trouble with the MQTT wildcard pattern for subscribing to the put order topics while supporting ETCD keys with /.

An additional topic for status about the MQTT2ETCD service (on-connect and LWT messages) get published on the Status topic (mqtt2etcd/status by default).

MQTT2ETCD (PUT)

• Default topic is mqtt2etcd/put/{key}, being {key} the full ETCD key of the entry
• Payload must be the value to set

ETCD2MQTT (Watch)

• Default topic is mqtt2etcd/stat/{key}, being {key} the full ETCD key of the entry
• Payload is the value of the entry

Installing (via Docker)

The recommended method to install is using the Python-Autoclonable-App image:

sudo docker run -d \
  -e GIT_REPOSITORY=https://github.com/David-Lor/MQTT2ETCD.git \
  -e GIT_BRANCH=develop \
  -e MQTT2ETCD_BROKER={mqtt_broker_ip} \
  -e MQTT2ETCD_HOST={etcd_server_ip} \
  -v /etc/timezone:/etc/timezone:ro \
  -v /etc/localtime:/etc/localtime:ro \
  --name mqtt2etcd \
  davidlor/python-autoclonable-app

If you want to run it locally:

git clone https://github.com/David-Lor/MQTT2ETCD.git
python MQTT2ETCD

Running tests

Install the requirements for the tests:

# After cloning...
cd MQTT2ETCD
pip install -r tests/requirements.txt
pytest