Getting started with mosquitto mqtt server

[jbbjarnason]

Starting

Using package manager

Either use system mosquitto package and init system, example:

sudo pacman -S mosquitto
sudo systemctl start mosquitto.service

Using docker

docker run --rm -it --name mqtt -v $(pwd)/mosquitto.conf:/mosquitto/config/mosquitto.conf -v $(pwd)/mosquitto_data:/mosquitto/data eclipse-mosquitto

A neat feature of docker is to run inspect to get the ip address of the container (given the name arg from above):

docker inspect mqtt

Configuration

Depending on the startup method you would either place it relative to where the docker container is started, when using package manager the default path is /etc/lib/mosquitto

Minimal config example

A non secure config example, mosquitto.conf:

allow_anonymous true
listener 1883
listener 9001
persistence true
persistence_file /mosquitto/data/mosquitto.db
log_type all
autosave_on_changes true

Simulating offline state

Forwarding the TCP traffic through socat can be used to simulate offline state, however, if you are using database and gracefully exit the broker it should write clients to database and clients can then regain session(of course depending on configuration). Example of using socat with docker based mosquitto server running at 172.18.0.2:

socat TCP4-LISTEN:1234,reuseaddr TCP4:172.18.0.2:1883

Clients can then connect to localhost:1234

Debugging database

Make a debugging database executable,

git clone https://github.com/eclipse/mosquitto/
cd mosquitto
make
./apps/db_dump/mosquitto_db_dump ~/mosquitto_data/mosquitto.db

Of course you need to point to your instance of database file.

Wireshark

Install it with your package manager and add your user to the wireshark group, example:

sudo pacman -S wireshark-qt
sudo usermod -a -G wireshark $USER
# restart or relogin

If you are using docker than the traffic is only on that interface (given that you are not running other containers).

TODO move to repository readthedocs

Move this later to repo