Hello together, I knew that in ROS1 there is a way to build a snap containing only roscore and build other packages as snaps than on top of the Ros runtime snap. Is this also possible? The Idea is to have a ROS2 foxy as a base snap and than for example an overlay snap "simple talker listener " as a snap which uses the Plug from ROS2 packed in the first snap?
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Hi @Mohamedaminhamdad,
I believe you are talking about the ‘content-sharing’ functionality of snaps applied to ROS 2 applications. This feature is not supported for ROS 2 at the moment but good news we are working on it! We’ll make sure to announce it both on the Ubuntu blog and here on the ROS Discourse so stay tune.
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Hey Jeremie,
what I meant is to overlay a workspace (Snap Listener/Talker) on top of a general ROS2 distribution (Snap 2) using plugs and slots. I’ve tried to do so. That’s what I’ve done so far, but still It didn’t work:
I have a snap containing ros2 foxy as a stand-alone ros-base. I’ve done that by building ros2 foxy using the colcon plugin and snapping the install folder, using the following snapcraft file.
name: ros-base
version: '0.1'
summary: Basic ROS2 listener component
description: |
Basic ROS2 listener component based on core20
grade: stable
confinement: strict
base: core20
parts:
dump:
plugin: colcon
stage-packages: [
ros-foxy-ros2launch,
ros-foxy-ros-core,]
build-environment:
- ROS_VERSION: '2'
- ROS_DISTRO: foxy
slots:
ros-base:
interface: content
content: executables
read: [/]
private: false
After that I tried to build an overlay snap (simple Hello World talker node) using the following snapcraft file,
name: overlay
version: '0.1'
summary: Basic ROS2 listener component
description: |
Basic ROS2 listener component based on core20
grade: stable
confinement: strict
base: core20
parts:
dump:
plugin: colcon
source: src
build-packages: [make, gcc, g++]
stage-packages: [ros-foxy-ros2launch, ros-foxy-common-interfaces]
override-build: |
snapcraftctl build
build-environment:
- ROS_VERSION: '2'
- ROS_DISTRO: foxy
wrapper-scripts:
plugin: dump
source: ./wrappers/
organize:
./wrapping.wrapper.sh : usr/bin/ros2-custom-ws
apps:
app4:
command: usr/bin/ros2-custom-ws
plugs:
ros-base:
interface: content
content: executables
target: $SNAP/mohamed
private: false
My wrapper file looks like that:
#!/bin/bash
ROS_BASE=$SNAP/mohamed
export PYTHONPATH=$PYTHONPATH:$ROS_BASE/usr/lib/python3.8/dist-packages:$PYTHONPATH
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$ROS_BASE/lib
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$ROS_BASE/lib/
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$ROS_BASE/usr/lib/$SNAPCRAFT_ARCH_TRIPLET/blas
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$ROS_BASE/usr/lib/$SNAPCRAFT_ARCH_TRIPLET/lapack
source $SNAP/mohamed/opt/ros/foxy/setup.bash
$SNAP/opt/ros/snap/lib/py_pubsub/talker
After connecting both snaps slots and plugs I can run the overlay snap using the following command: overlay.app4 Howevere, when doing so, I get the following error:
/bin/bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)
Traceback (most recent call last):
File "/snap/overlay/x1/opt/ros/snap/lib/py_pubsub/talker", line 6, in <module>
from pkg_resources import load_entry_point
File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 3254, in <module>
def _initialize_master_working_set():
File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 3237, in _call_aside
f(*args, **kwargs)
File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 3266, in _initialize_master_working_set
working_set = WorkingSet._build_master()
File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 584, in _build_master
ws.require(__requires__)
File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 901, in require
needed = self.resolve(parse_requirements(requirements))
File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 787, in resolve
raise DistributionNotFound(req, requirers)
pkg_resources.DistributionNotFound: The 'py-pubsub==0.0.0' distribution was not found and is required by the application
My workspace for my overlay ros snap looks like that:
├── snap
│ └── snapcraft.yaml
├── src
│ └── py_pubsub
│ ├── launch
│ │ └── publisher_launch.py
│ ├── package.xml
│ ├── py_pubsub
│ │ ├── __init__.py
│ │ └── publisher_member_function.py
│ ├── resource
│ │ └── py_pubsub
│ ├── setup.cfg
│ ├── setup.py
│ └── test
│ ├── test_copyright.py
│ ├── test_flake8.py
│ └── test_pep257.py
└── wrappers
└── wrapping.wrapper.sh
after modifying the wrapper and sourcing the ./local_setup.bash.
#!/bin/bash
ROS_BASE=$SNAP/mohamed
export PYTHONPATH=$PYTHONPATH:$ROS_BASE/usr/lib/python3.8/dist-packages
export PYTHONPATH=$PYTHONPATH:$ROS_BASE/usr/lib/python3/dist-packages
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$ROS_BASE/lib
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$ROS_BASE/lib/$TRIPLET
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$ROS_BASE/usr/lib
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$ROS_BASE/usr/lib/$TRIPLET
source $SNAP/mohamed/opt/ros/foxy/setup.bash
source $SNAP/local_setup.bash && $SNAP/py_pubsub/lib/py_pubsub/talker
The distribution py_pubsub is found. Howevere, now i get the following error:
/bin/bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)
Traceback (most recent call last):
File "/snap/overlay/x1/py_pubsub/lib/py_pubsub/talker", line 33, in <module>
sys.exit(load_entry_point('py-pubsub==0.0.0', 'console_scripts', 'talker')())
File "/snap/overlay/x1/py_pubsub/lib/py_pubsub/talker", line 25, in importlib_load_entry_point
return next(matches).load()
File "/usr/lib/python3.8/importlib/metadata.py", line 77, in load
module = import_module(match.group('module'))
File "/usr/lib/python3.8/importlib/__init__.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
File "<frozen importlib._bootstrap>", line 991, in _find_and_load
File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 848, in exec_module
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "/snap/overlay/x1/py_pubsub/lib/python3.8/site-packages/py_pubsub/publisher_member_function.py", line 2, in <module>
from rclpy.node import Node
File "/snap/overlay/x1/mohamed/opt/ros/foxy/lib/python3.8/site-packages/rclpy/node.py", line 42, in <module>
from rclpy.client import Client
File "/snap/overlay/x1/mohamed/opt/ros/foxy/lib/python3.8/site-packages/rclpy/client.py", line 22, in <module>
from rclpy.impl.implementation_singleton import rclpy_implementation as _rclpy
File "/snap/overlay/x1/mohamed/opt/ros/foxy/lib/python3.8/site-packages/rclpy/impl/implementation_singleton.py", line 31, in <module>
rclpy_implementation = _import('._rclpy')
File "/snap/overlay/x1/mohamed/opt/ros/foxy/lib/python3.8/site-packages/rclpy/impl/__init__.py", line 28, in _import
return importlib.import_module(name, package='rclpy')
File "/usr/lib/python3.8/importlib/__init__.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
ImportError: libspdlog.so.1: cannot open shared object file: No such file or directory
The C extension '/snap/overlay/x1/mohamed/opt/ros/foxy/lib/python3.8/site-packages/rclpy/_rclpy.cpython-38-x86_64-linux-gnu.so' failed to be imported while being present on the system. Please refer to 'https://index.ros.org/doc/ros2/Troubleshooting/Installation-Troubleshooting/#import-failing-even-with-library-present-on-the-system' for possible solutions
Hi @Mohamedaminhamdad,
The ROS Discourse isn’t really the place to address help queries. Since you’ve also open a thread on the Snapcraft forum I will take the discussion over there.