The ros-opt-data
interface creates a read-only mount from within a snap to the standard Robot Operating System (ROS) directory (/opt/ros/*
) on the host system, enabling robotics-based snaps to share ROS robot data, such as the URDF.
This interface cannot currently be used on Ubuntu Core. Requires snapd version 2.62+.
To add this interface to a snap, define a plug in the app section of its snapcraft.yaml for the application that requires ROS data access:
apps:
hello-world:
command: ./hello.sh
plugs: [ros-opt-data] #this is the new interface plug name
This interface uses the standard snap location for mounted directories:
/var/lib/snapd/hostfs/
.
For example, if this interface is used to access /opt/ros/noetic/robot-urdf/models
on the host machine, it will be found within the snap at /var/lib/snapd/hostfs/opt/ros/noetic/robot-urdf/models
.
See Interface management and Supported interfaces for further details on how interfaces are used.
Auto-connect: yes
The following is a simple hello-world example that includes an additional plug/slot mechanism for enabling the ros-opt-data
interface. We’re going to modify this example to show how the interface can access ROS-related data on the host system.
The initial snapcraft.yaml is as follows:
name: hello-world
version: '0.1'
summary: A simple hello world application
description: |
A simple hello world application.
base: core22
grade: devel
confinement: strict
apps:
hello-world:
command: ./hello.sh
parts:
hello-world:
plugin: dump
source: files
When the snap is built, installed and executed, it runs the following hello.sh
script (which for now only outputs “hello world”).
#!/bin/bash
echo "hello world"
We now want to change the above script to output the contents of a setup.bash
file located in the host’s /opt/ros
directory.
The following modification assumes we’re using ROS Noetic Ninjemys, but the file location can be adapted for any other ROS distro:
#!/bin/bash
cat /var/lib/snapd/hostfs/opt/ros/noetic/setup.bash
We now modify the snapcraft.yaml to insert the new plug:
name: hello-world
version: '0.1'
summary: A simple hello world application
description: |
A simple hello world application.
base: core22
grade: devel # must be 'stable' to release into candidate/stable channels
confinement: strict
apps:
hello-world:
command: ./hello.sh
plugs: [ros-opt-data]
parts:
hello-world:
plugin: dump
source: files
When the new snap is built, installed and executed, the output will now be the contents of /opt/ros/noetic/setup.bash
.
The test code can be found in the snapd repository: https://github.com/snapcore/snapd/blob/master/interfaces/builtin/ros_opt_data_test.go
The source code for the interface is in the snapd repository: https://github.com/snapcore/snapd/blob/master/interfaces/builtin/ros_opt_data.go
Last updated 4 months ago.