Rosbridge Compatibility

Rosbridge WebSocket Compatibility

All the requests to deployment endpoints on rapyuta.io goes through a secure proxy which routes the requests to different backends. When running behind such a reverse proxy, rosbridge_websocket fails at the connection handshake when the port in the request header is different from the port the deployment is running on (e.g., the default 9090).

To workaround this limitation,

  1. An additional argument, websocket_external_port needs to be included in the launch spec and should be set to the port 80
  2. The rosbridge_suite repo needs to be added as a git submodule into your workspace.

An example launch spec would look something like this:

<launch>
    <arg name="ws_port"    default="$(optenv WS_PORT 9090)" />
    <arg name="ws_address" default="$(optenv WS_ADDR 0.0.0.0)" />
    <arg name="websocket_external_port" default="80" />

    <include file="$(find rosbridge_server)/launch/rosbridge_websocket.launch">
        <arg name="port"    value="$(arg ws_port)" />
        <arg name="websocket_external_port"    value="80" />
        <arg name="address" value="$(arg ws_address)" />
    </include>
</launch>

The command center package in the quick walkthrough can be used as a reference as to how to pass websocket_external_port.

Some things to note in the example command center package mentioned above:

  1. The PR for the external port feature has not been released and packaged yet (as on 13/04/2020). To include this, the rosbridge_suite repo (devel branch) is added as a git submodule into the io_tutorials repository. You can choose to add a different commit other than devel, as long as it includes the commits in the above linked PR.
  2. The launch file of the command center at io_turtlesim/io_turtle_command_center/launch/command_center.launch has an additional argument called websocket_external_port and should be set to 80 to workaround this bug.

P.S.: - This github PR and the issues linked under it, throws more light on the issue and the need for external port: https://github.com/RobotWebTools/rosbridge_suite/pull/468

There are PRs pending to fix this issue in the upstream. This workaround will be there till the following PRs are merged.