RO2ERL Bridge

A bridge component for the Target-X system that connects local ROS2/DDS networks to the central hub.

Overview

ro2erl_bridge is a component in the Target-X system that:

1. Connects to the central hub
2. Forwards messages from the local ROS2/DDS network to the hub
3. Receives messages from the hub and forwards them to the local network

For detailed design information, see:

• Bridge Design Documentation
• RO2ERL Documentation

Features

• Hub discovery and automatic registration
• Message forwarding to/from the hub
• Message filtering (future)
• Customizable local dispatch callback

Requirements

• Erlang/OTP 27 or later
• rebar3

Installation

ro2erl_bridge is designed to be used as a dependency within your own Erlang application:

%% rebar.config
{deps, [
    {ro2erl_bridge, {git, "https://github.com/stritzinger/ro2erl_bridge.git"}}
]}.

Configuration

Configure ro2erl_bridge in your application's sys.config:

{ro2erl_bridge, [
    {dispatch_callback, {my_app, handle_message}}
]}.

Where:

• dispatch_callback: A function that will be called when a message is received from the hub. It can be specified as {Module, Function} or {Module, Function, Args}.

Development

Start Without TLS Distribution

Start an interactive shell with debug logging and a specific node name:

ERL_FLAGS='-connect_all false' rebar3 shell --sname bridge --setcookie targetx

Start With TLS Distribution

To start a local development shell with support for TLS distribution, you need first to generate a testing CA and certificate:

local/setup.sh ../ro2erl_hub

Then you can start the shell with:

ERL_FLAGS='-proto_dist inet_tls -ssl_dist_optfile local/ssl_dist_opts.rel -connect_all false' rebar3 as local shell --sname bridge --setcookie targetx

Connecting to Hub

In the Erlang shell, connect to the hub:

1> net_adm:ping(list_to_atom("hub@" ++ lists:nth(2, string:split(atom_to_list(node()), "@")))).
pong

API

Dispatch a message to the hub:

2> ro2erl_bridge:dispatch(foobar).

Run tests

rebar3 ct

Production Deployment

For production deployment on grisp.io:

# Build the release with production dependencies
rebar3 as prod release

# Build the Docker image for deployment
rebar3 as prod docker

# Push the image to your registry
docker push local/ro2erl_bridge:0.1.0 your-registry/ro2erl_bridge:0.1.0

The production build includes the braidnode dependency which is required for deployment on grisp.io. This dependency is not included in the development environment to simplify local testing.

Usage

Sending Messages to Hub

To send a message from the local ROS2 network to the hub:

ro2erl_bridge:dispatch(Message).

Receiving Messages from Hub

Messages received from the hub will be passed to the configured dispatch_callback function. This function should be defined in your application:

-module(my_app).

-export([handle_message/1]).

handle_message(Message) ->
    %% Process the message received from the hub
    ok.

Dependencies

• Erlang/OTP 27 or later
• rosie_rclerl (for ROS2 integration)

License

Copyright © 2025 Stritzinger GmbH

Licensed under the Apache License, Version 2.0. See LICENSE file for details.