python-simple-mqtt-k3s

This project is a simple example of containerizing an application that publishes to an MQTT broker. It has been tested with mosquitto running on premise, but should work with any mqtt (eg. adafruit.io, etc). You may need to set the parameters (ip, port, username, etc).

Installation

This application is meant to be installed on a kubernetes cluster, for example, I have a small raspberry pi cluster running k3s. But it should work on any kubernetes cluster (gke, etc).

Currently automated builds are configured for arm64 and amd64. The auto-build containers are available at:

ghcr.io/lila/python-simple-mqtt-k3s:main

Usage

There is no usage. it just generates a simple time series that is supposed to be temperature, and runs for ever. but you can set some of the parameters:

• MQTT_HOST:
• MQTT_PORT:
• MQTT_TOPIC:
• MQTT_SLEEP_DURATION:

To run on the commandline, use:

 docker run --env "MQTT_DEBUG=true" --env "MQTT_HOST=192.168.86.4"  ghcr.io/lila/python-simple-mqtt-k3s:main

Of course, use your own MQTT Broker IP address. To run it in kubernetes:

kubectl create -f deploy.yaml

the deployment yaml is very simple, you can configure it with the environment variables as needed:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: python-simple-mqtt
spec:
  selector:
    matchLabels:
      app: python-simple-mqtt
  template:
    metadata:
      labels:
        app: python-simple-mqtt
    spec:
      containers:
        - name: python-simple-mqtt
          image: "ghcr.io/lila/python-simple-mqtt-k3s:main"
          env:
            - name: MQTT_HOST
              value: "192.168.86.4" 
            - name: MQTT_DEBUG
              value: "true"

publish calendar events

In addition to the simple numerical example, I added a more complex example that connects to google calendar api to retrieve your current calender events and publishes the json to the mqtt broker.

Setup is more complex, as you need to get the api keys, see ./secrets for a template. See here: https://learn.adafruit.com/pyportal-google-calendar-event-display/code-setup
for details on how to get the api keys from google calendar.

Once you add your keys to secrets/secrets.py, you will need to create a kubernetes secret with the keys installed and mount it into the pod for the application. Run

kubectl create secret generic gcal-credentials --from-file ./secrets.py

and use the following for the application deployment:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: python-simple-mqtt
spec:
  replicas: 1
  selector:
    matchLabels:
      app: python-simple-mqtt
  template:
    metadata:
      labels:
        app: python-simple-mqtt
    spec:
      nodeSelector:
        nodetype: pi3
      containers:
        - name: python-simple-mqtt
          image: "ghcr.io/lila/python-simple-mqtt-k3s:main"
          imagePullPolicy: Always
          env:
            - name: MQTT_HOST
              value: "192.168.86.4" 
            - name: MQTT_DEBUG
              value: "true"
            - name: MQTT_APP
              value: "gcal.py"
            - name: MQTT_SLEEP_DURATION
              value: "120"
          volumeMounts:
            - mountPath: "/app/secrets"
              name: credentials
              readOnly: true
      volumes:
        - name: credentials
          secret:
            secretName: gcal-credentials

It uses the same container, but adds an environment variable (MQTT_APP) to tell it to run the other app. the secret credentials get mounted in /app/secrets for the app to use.

Contributing

Pull requests are welcome. or just fork and do what you want.

Please make sure to update tests as appropriate.

License

MIT