Error using ros.ros2.internal.createOrGetLocalPython
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Hello,
Recently I encountered the following error when trying to call ros2genmsg. Anyone can help? Thanks in advance.
Error using ros.ros2.internal.createOrGetLocalPython (line 133)
Could not install the required Python packages: Looking in links:
/var/home/alex/opt/MATLAB/R2020a/sys/ros2/share/python
Processing /var/home/alex/opt/MATLAB/R2020a/sys/ros2/share/python/argcomplete-1.10.0-py2.py3-none-any.whl
Processing /var/home/alex/opt/MATLAB/R2020a/sys/ros2/share/python/flake8-3.7.8-py2.py3-none-any.whl
Processing /var/home/alex/opt/MATLAB/R2020a/sys/ros2/share/python/flake8-blind-except-0.1.1.tar.gz
Processing /var/home/alex/opt/MATLAB/R2020a/sys/ros2/share/python/flake8_class_newline-1.6.0-py3-none-any.whl
Processing /var/home/alex/opt/MATLAB/R2020a/sys/ros2/share/python/flake8_comprehensions-2.1.0-py3-none-any.whl
Processing /var/home/alex/opt/MATLAB/R2020a/sys/ros2/share/python/flake8_docstrings-1.3.0-py2.py3-none-any.whl
Processing /var/home/alex/opt/MATLAB/R2020a/sys/ros2/share/python/flake8_import_order-0.18.1-py2.py3-none-any.whl
Processing /var/home/alex/opt/MATLAB/R2020a/sys/ros2/share/python/flake8-quotes-2.0.1.tar.gz
Processing /var/home/alex/opt/MATLAB/R2020a/sys/ros2/share/python/pytest-5.0.1-py3-none-any.whl
Processing /var/home/alex/opt/MATLAB/R2020a/sys/ros2/share/python/pytest_cov-2.7.1-py2.py3-none-any.whl
Processing /var/home/alex/opt/MATLAB/R2020a/sys/ros2/share/python/pytest_runner-5.1-py2.py3-none-any.whl
Processing /var/home/alex/opt/MATLAB/R2020a/sys/ros2/share/python/pytest_repeat-0.8.0-py2.py3-none-any.whl
Processing /var/home/alex/opt/MATLAB/R2020a/sys/ros2/share/python/pytest_rerunfailures-7.0-py2.py3-none-any.whl
Processing /var/home/alex/opt/MATLAB/R2020a/sys/ros2/share/python/colcon_common_extensions-0.2.0-py3-none-any.whl
Processing /var/home/alex/opt/MATLAB/R2020a/sys/ros2/share/python/lark-parser-0.7.2.tar.gz
[31mERROR: Could not find a version that satisfies the requirement numpy (from versions: none)[0m
[31mERROR: No matching distribution found for numpy[0m
. Verify there is space on disk to create the packages and retry the command.
Error in ros2genmsg (line 53)
ros.ros2.internal.createOrGetLocalPython(); %ensure python is available
For reference,
>> pyenv
ans =
PythonEnvironment with properties:
Version: "3.8"
Executable: "/var/home/alex/miniconda3/envs/matlab/bin/python"
Library: "/var/home/alex/miniconda3/envs/matlab/lib/libpython3.8.so"
Home: "/var/home/alex/miniconda3/envs/matlab"
Status: NotLoaded
ExecutionMode: InProcess
Risposta accettata
Cam Salzberger
il 27 Lug 2020
0 voti
Hello Alexander,
There is unfortunately an issue with the current documentation, which should be updated soon. Instead of Python 3.7+, you need exactly Python 3.7 to use ROS 2 custom messages or code generation with MATLAB. Once you install Python 3.7 and point MATLAB to use it with pyenv('Version', <executable path>), it should work.
-Cam
12 Commenti
Alexander Wang
il 27 Lug 2020
Modificato: Alexander Wang
il 27 Lug 2020
Alexander Wang
il 28 Lug 2020
Again, when I try to create a message
Warning: Name is nonexistent or not a directory:
/var/home/alex/devel/finger_perception/custom/matlab_msg_gen/glnxa64/install/m
> In path (line 109)
In addpath (line 86)
In ros.internal.getEmptyMessage (line 17)
In ros2message (line 37)
In ros2message (line 43)
In ros2message (line 43)
Error using ros.internal.getEmptyMessage (line 25)
Unrecognized message type tactile_msgs/TactileSignal. Use ros2 msg list to see available types.
Error in ros2message (line 37)
msg = ros.internal.getEmptyMessage(messageType,'ros2');
43 rethrow(ex)
but
ros2 msg list
shows that the message type has been generated...
Cam Salzberger
il 28 Lug 2020
Hey Alexander,
I'm a bit worried about you having changed the code inside of ColconBuilder, as that should work without any modification. That section of the code should be:
cmdline = sprintf('%s ',varargin{:});
cmdmap = containers.Map({'win64','maci64','glnxa64'}, ...
{['"' fullfile(fileparts(mfilename('fullpath')),'runcolconcmd') '" "' strtrim(h.MexInfo.Details.CommandLineShell) '"'], ...use .bat file
['"' fullfile(fileparts(mfilename('fullpath')),'runcolconcmd.sh') '"'],... use .sh
['"' fullfile(fileparts(mfilename('fullpath')),'runcolconcmd.sh') '"']});
cmd = cmdmap(computer('arch'));
The "cmdmap" here is just used to determine which batch file or shell script should be used depending on which platform you are on. From the error message, it looks like your code was missing the second half of the "Windows" line (everything after "strtrim"). Make sure you haven't moved this file either, as it uses that to determine the location of the shell script. It shouldn't really be possible for it to not return a value to cmdmap.
Also, a little background about what createOrGetLocalPython is doing. There are several non-standard Python packages required for ROS 2. Rather than requring users to install them, this creates a Python virtual environment (venv) and installs those Python modules to the virtual environment. Then whenever it needs to run any Python commands (mostly running colcon build), it activates the virtual environment and uses that. Once this virtual environment gets created, it can be used from then on ("getting" rather than "creating" the Python environment). This lets it be only a one-time setup time-sink rather than requiring the setup every time.
You shouldn't need to personally modify the Python virtual environment - it should have everything it needs from the module install. There's a possibility that it got created in a bad state though, but continues to try to use it. You can force MATLAB to recreate the virtual environment from scratch with:
ros.ros2.internal.createOrGetLocalPython(true)
(the "true" argument forces the recreation)
One thing that can help, after running "ros2genmsg" is to check the build log link that gets output. This is the raw colcon build log file, so you can skim/search it for any errors or warnings if something is coming up weird.
The message showing in "ros2 msg list" means that the message got registered as a custom message with MATLAB, and the location of the message definition file exists and is known (as that is how "ros2 msg list" determines availability of messages). However, it seems that the expected MATLAB file for generating the default message did not get created (should be in this relative location: matlab_msg_gen/glnxa64/install/m). That seems to indicate the build not fully completing without some kind of error stopping it early.
To summarize my suggestion:
- Put the code in ColconBuilder/runColconCmd back to how it was, but make sure it matches what I showed (lines 72-77).
- Run ros.ros2.internal.createOrGetLocalPython(true)
- Try ros2genmsg again, and check the build log for any odd output
- Check that the folder matlab_msg_gen/glnxa64/install/m is created, and contains a file for your message type
-Cam
Alexander Wang
il 28 Lug 2020
Modificato: Alexander Wang
il 28 Lug 2020
Cam Salzberger
il 28 Lug 2020
Ah, I think I've figured it out. The issue is with this portion of the command:
strtrim(h.MexInfo.Details.CommandLineShell)
The value contained in h.MexInfo comes from:
mex.getCompilerConfigurations('C++')
I would bet that if you ran that, you would get an empty object result (0x1 CompilerConfiguration). That will cause the first line there to fail with your error.
I'm actually surprised it managed to attempt a colcon build without the compiler being set, since it requires that to perform the build. Colcon must be picking up the default installation location of the compiler. You should be able to resolve this by running:
mex -setup C++
and following the prompts from there. You can see supported compilers for your OS for ROS 2 listed here or even here.
Hmm, though if that's the case, I wouldn't think it would get past line 157 in ros2genmsg, since that should be where it checks the compiler version for compatibility. When I run after removing my selected compiler, that's where it errors for me. Well, at least make sure you run the mex -setup and check the getCompilerConfigurations output. Let me know that information if it still doesn't work.
I have never tested this with or used Conda environments before, so I can't speak for whether it might cause issues or not, though it doesn't seem to be the cause of this specific issue. You don't need to have any ROS 2 libraries installed on your system to use ROS 2 in MATLAB.
-Cam
Alexander Wang
il 28 Lug 2020
Modificato: Alexander Wang
il 28 Lug 2020
Cam Salzberger
il 28 Lug 2020
Modificato: Cam Salzberger
il 28 Lug 2020
Did you run this again?
ros.ros2.internal.createOrGetLocalPython(true)
That kind of error usually shows up only if the Python packages fail to fully install to the virtual environment (numpy installs last).
If that still doesn't work, and you are alright with modifying your Python 3.7 installation, you could try adding numpy to it? Make sure it's the 3.7 installation that you are modifying:
python3 -m pip install --upgrade numpy
Then rerun the createOrGetLocalPython command above to recapture the new state of the base Python.
One other possibility is the final dependency for custom messages. You have Python 3.7 and the supported compiler (gcc 6.3 or Xcode 10), but it also requires CMake of at least a particular version. We've tested for R2020a with CMake 3.10+, but I did see one instance of an issue with an unusual setup and a CMake version below 3.13 that was unable to properly find the Python paths. First, what is your current CMake version:
cmake --version
Next, you could try updating it to the latest release. I've personally tested with 3.15 and 3.17, so one of those should be fine too.
Side note: Are you on Mac or Linux? What OS and version?
-Cam
Alexander Wang
il 28 Lug 2020
Unfortunately the problem persists.
I did follow all your steps and have installed numpy. I also checked pip list in the python_venv created by Matlab, numpy is presented
Besides,
I also tried manually append the numpy include directory to $CFLAGS, but it didn't help at all.
Cam Salzberger
il 28 Lug 2020
What OS and version are you using? I want to try to reproduce this if possible.
I have seen one other instance where having Python 3.8 available, while trying to use Python 3.7, is actually causing issues. The issues didn't look anything like this one, but it might be worth trying. Run this within MATLAB:
getenv('PATH')
and see if there is any mention of Python 3.8 in there. If so, try removing removing it and setting the environment variable to the new value without it. If you do this just within MATLAB, it won't affect your environment outside of it.
-Cam
Alexander Wang
il 29 Lug 2020
Modificato: Alexander Wang
il 29 Lug 2020
Alexander Wang
il 31 Lug 2020
Andrei Alexeev
il 10 Ago 2021
Hello together,
for last few days I also had problems to generate the custom messages.
Finally I came across the right solution and would like to briefly show what steps are needed to install it correctly.
To build the custom messages you need CMake, Python 3.7 and the ROS Toolbox.
For CMake:
1. go to https://cmake.org/download/
2. download version 3.20.5 as *.sh
mkdir ~/cmake-install
mv cmake-<version>.sh ~/cmake-install/
% move to ~/cmake-install/ and execute installer
./cmake-<version>.sh
% Finally add these lines to ~/.bashrc
export PATH=$HOME/cmake-install/bin:$PATH
export CMAKE_PREFIX_PATH=$HOME/cmake-install:$CMAKE_PREFIX_PATH
For Python:
For this I installed version 3.7+.
% install dependencies
sudo apt update
sudo apt install build-essential zlib1g-dev libncurses5-dev libgdbm-dev libnss3-dev libssl-dev libreadline-dev libffi-dev wget
cd /tmp
% download python 3.7+
wget https://www.python.org/ftp/python/3.7.2/Python-3.7.2.tar.xz
tar -xf Python-3.7.2.tar.xz
cd Python-3.7.2
% prepare for compiling. --enable-shared is important when linking
% libpython
./configure --enable-shared
make
sudo make altinstall
When building custom messages colcon will need numpy-headers.
Attention: It does not have to be the 3.7.2 installation where you install numpy. Colcon does not care about the virtual environment which ros2 creates.
% install numpy
python3 -m pip install numpy
---
Now run Matlab and hit pyenv. If Version 3.7.2 does not appear, hit:
pyenv('Version', "</path/to/python3.7>")
Check also if CMake has been installed correctly. Hit
% No errors should appear
!cmake --version
From here everything should work fine. Select your path to your messages und run the build.
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