This is a simple script to listen to MQTT messages and store them into a JSONL file. This JSONL file can then be replayed at a later date, which is useful for testing MQTT systems.
I had a quick look on the Internet and could not see anything similar, though it likely exists, this just helps me at the moment.
TODO: Fix this when I understand how to package things properly
This is a python3 script, if that does not match your requirements, please look elsewhere.
This is my first python code, so I have not created an account with PyPI or whatever, so you need to install from this dist
install it
pip install -r requirements.txt
pip install -e .
This will make the script mqtt2jsonl available either in the virtualenv you are running in or your complete environment
If you want to make changes and rebuild, remember to update the version number in the pyproject.toml file.
Assumption that you are using linux/unix otherwise prefix the command with python3, assuming your other OS has python3 installed and its accessible from a command prompt.
Help is available
./mqtt2jsonl -h
usage: mqtt2jsonl [-h] [-v] [-f] [-j JSONL] [-s SERVER] [-p PORT] [-t TOPIC] [-d DELAY] cmd
Either record or replay MQTT via a JSONL file
positional arguments:
cmd Command to perform against the MQTT topic queue, 'record' or 'replay'
options:
-h, --help show this help message and exit
-v, --verbose Increase level of logging from WARNING to INFO
-f, --force Force overwrite when destination file already exists
-j JSONL, --jsonl JSONL
JSONL file to read from or write to
-s SERVER, --server SERVER
MQTT server name/ip to connect to (localhost)
-p PORT, --port PORT MQTT port to connect to (1883)
-t TOPIC, --topic TOPIC
MQTT topic queue to listen to (for recording), usual wildcards apply (default everying as '#')
-d DELAY, --delay DELAY
For replay, override the recorded delay between messages to use an artifical
value in msecs, 0 means use record value
Connect to default localhost port 1883, with a wildcard topic, overwriting any previous file
./mqtt2jsonl -j /tmp/record.jsonl record -t 'some_topic/#' -f
Connect to to named server and port, use default topic of everything (#)
./mqtt2jsonl -j /tmp/record.jsonl record --server some_mqtt_server --port 1000
Connect to default localhost port 1883, replay at the recorded rate
./mqtt2jsonl -j /tmp/record.jsonl replay
Connect to to named server and port, replay at a fast rate of one message per 5ms
./mqtt2jsonl -j /tmp/record.jsonl record --server some_mqtt_server --port 1000 --delay=5
There are a few things that could possibly make this a better more general tool but I don't need these features right now
- Create a PyPI account and upload it there
- Log in with a username/password
- Log into a MQTT server that uses TLS