The work presented here is supported by the RoboSAPIENS project funded by the European Commission's Horizon Europe programme under grant agreement number 101133807.

MQTT:

For a minimum example of running with MQTT, run the following specification:

cargo run -- examples/simple_add.lola --mqtt-input --mqtt-output

In MQTT Explorer or similar, send the following message on the topic "x" followed by sending the same message on the topic "y":

42

The following result should be visible on the "z" topic:

{
    "value": 84
}

Note:

If you want to provide e.g., a Deferred value then it must be done with:

{
    "Deferred": null
}

MQTT - Legacy syntax:

For a minimum example of running with MQTT, run the following specification:

cargo run -- examples/simple_add.lola --input-mqtt-topics x y --output-mqtt-topics z

Follow the same syntax for sending to topics as decribed above.

Note:

If you have auxiliary streams they must currently also be specified in output-mqtt-topics but they are not outputted through MQTT. This is a current limitation.

ROS2:

For a minimum example of running with ROS2 open a terminal and source ROS2. Then run colcon to compile the custom message types:

colcon build

And source the install file:

source install/setup.bash

Start monitoring the specification:

cargo run --features ros -- --input-ros-topics examples/counter_ros_map.json examples/counter.lola

In another terminal, source ROS2 and run the following command:

ros2 topic pub /x std_msgs/msg/Int32 "{data: 1}"

The output in the first terminal should now be counting forever.

Distribution - local node:

In terminal 1: cargo run -- examples/simple_add_distributable.lola --mqtt-input --mqtt-output --distribution-graph examples/simple_add_distribution_graph.json --local-node A

In terminal 2: cargo run -- examples/simple_add_distributable.lola --mqtt-input --mqtt-output --distribution-graph examples/simple_add_distribution_graph.json --local-node B

Use an MQTT client: Publish 1 to topic x, publish 2 to topic y. Observe that w is calculated. Publish 3 to topic z. Observe that v is calculated.