41 lines
1.5 KiB
Markdown
41 lines
1.5 KiB
Markdown
# Rules for programming with Python in ROS2
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## File Structure
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```
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colcon_workspace
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|- build (holds build files)
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|- install (holds build elements)
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|- src (contains your source code - this is where you work)
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```
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## Colcon Build
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Performing a `colcon build` is neccessary after every change to the `src` directory. This must be performed in the `root` of the _colcon_ workspace (eg. `cd ~/colcon_ws`).
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In order to avoid this procedure after every change made to a Python script you must run `colcon build --symlink-install` once. This links the files created in `/build` and `/install` to your source files in `/src`. However, after creating a new Python script this procedure must be repeated in order to also link this new script.
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## Source Directory
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The source directory holds your ROS2 packages as further directories. In this example the `src` directory contains the packages `pubsub` and `pubsub_msg`:
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```
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colcon_workspace/
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|- src/
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|- pubsub/
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|- pubsub_msg/
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```
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## setup.py
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The file `<colcon_ws>/<package_dir>/setup.py` defines how to call your scripts using the command line. This results in commands such as
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`ros2 run pubsub talker`
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`ros2 run pubsub listener`.
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This is done by linking the names _talker_ and _listener_ to the Python scripts of your choice, eg.
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```python
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entry_points={
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'console_scripts': [
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'talker = pubsub.talker:main',
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'listener = pubsub.listener:main'
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],
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},
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```
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