MQTT Broker and Client communication

This is a rather simple setup of a MQTT broker and a client.
It serves as a starting point for a uni project.
The services are created and managed via docker compose.
This readme explains rather unnecessary steps quite exentsively for further studies and also as a note to myself.

Forward to these topics if you just want to ...

compose and start the containers
use the scripts

Project Overview
Starting the docker container manually
After container is started
Create shared network between containers
Docker commands
Using the scripts
Author

Project overview

/docker/ : Contains the Dockerfiles for MQTT broker and client
/volumes/ : Contains the docker volumes which are mounted into the containers
- /mqtt/mqtt_config/ : Contains the MQTT config file
- /mqtt/mqtt_data/ : Contains the MQTT database
- /mqtt/mqtt_log/ : Contains the MQTT logs
- /scripts/publisher/ : Contains the publisher script for the broker
- /scripts/subscriber/ : Contains the subscriber script for the client
.env : Contains Variables used in docker-compose.yml
docker-compose.yml : The docker compose file

Starting the docker container manually

Run mqtt-broker MQTT container:

docker run --name mqtt-broker --hostname=8b6c8703a75d --mac-address=02:42:ac:11:00:02 --env=PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin --env=VERSION=2.0.15 --env=DOWNLOAD_SHA256=4735b1d32e3f91c7a8896741d88a3022e89730a1ee897946decfa0df27039ac6 --env=GPG_KEYS=A0D6EEA1DCAE49A635A3B2F0779B22DFB3E717B7 --env=LWS_VERSION=4.2.1 --env=LWS_SHA256=842da21f73ccba2be59e680de10a8cce7928313048750eb6ad73b6fa50763c51 --volume=mqtt_data:/mosquitto/data --volume=mqtt_config:/mosquitto/config --volume=mqtt_log:/mosquitto/log -p 1883:1883 --restart=no --label='description=Eclipse Mosquitto MQTT Broker' --label='maintainer=Roger Light <roger@atchoo.org>' --runtime=runc -d eclipse-mosquitto

Change content of /mosquitto/config/mosquitto.conf to:

persistence true
persistence_location /mosquitto/data/
user mosquitto
listener 1883
allow_anonymous true
log_dest file /mosquitto/log/mosquitto.log
log_dest stdout

Run mqtt-client-01 Alpine container:

docker run -ti --name mqtt-client01 --hostname=c2b6b137cfa2 --env=PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin --volume=mqtt_client_01:/home/mqtt_client_01/ --runtime=runc -d alpine:latest

Run mqtt-client-01 Ubuntu container:

docker run -ti --name mqtt-client01 --hostname=c2b6b137cfa2 --env=PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin --volume=mqtt_client_01:/home/mqtt_client_01/ --runtime=runc -d ubuntu:latest

After container is started

MQTT Broker (Alpine) Dependencies/Commands:

apk add --no-cache python3
apk add --no-cache py3-pip
pip3 install paho-mqtt

Client (Alpine) Dependencies/Commands:

apk add python3 --no-cache
apk add py3-pip --no-cache
pip3 install paho-mqtt

Client (Ubuntu) Dependencies/Commands:

apt install python3
apt install python3-pip
python3 -m pip install paho-mqtt

Optional:
apt install mosquitto
apt install systemctl
systemctl start mosquitto
apt install iputils
apt install iproute2
apt install nano

Create shared network between containers

This short tutorial shows how to create a shared network in docker so the containers can communicate with each other using the example of two apache-php containers and the network 'myNetwork'. (Needles to say) you have to change the parameters according to your project.

Create two containers:

docker run -d --name web1 -p 8001:80 eboraas/apache-php docker run -d --name web2 -p 8002:80 eboraas/apache-php

Important note: it is very important to explicitly specify a name with --name for your containers otherwise I’ve noticed that it would not work with the random names that Docker assigns to your containers.

Then create a new network:

docker network create myNetwork

After that connect your containers to the network:

docker network connect myNetwork web1
docker network connect myNetwork web2

Check if your containers are part of the new network:

docker network inspect myNetwork

Then test the connection:

docker exec -ti web1 ping web2

Docker commands

Compose and start the containers:

docker-compose up -d

Stop and remove all containers only:

docker-compose down

Stop and remove all containers and images (used by any service in the compose file):

docker-compose down --rmi all

Access a Docker container shell:

docker exec -it <CONTAINER_NAME_OR_ID> /bin/sh

Examples:

docker exec -it mqtt-client-1 /bin/sh
docker exec -it mqtt-broker-1 /bin/sh

Remove unused builder resources and dangling builder cache:

docker builder prune

Using the scripts

First you want to compose the docker containers
Connect to the container shells via Docker Desktop GUI or via shell
Then execute the corresponding python scripts:

On broker:

python3 /home/scripts/publisher/prompt_publisher.py

On client:

python3 /home/scripts/subscriber/subscriber.py

The broker IP must be changed in /home/scripts/subscriber/config.py accordingly!

Author

yuncam

yuncam/mqtt