first test push

2021-01-13 15:28:01 +01:00 · 2021-01-13 15:28:01 +01:00 · c98972e4a9
commit c98972e4a9
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--- a/Links.md
+++ b/Links.md
@ -0,0 +1,4 @@
+# Links for during ROS Workshop
+
+ros_tutorials: https://github.com/ros/ros_tutorials.git
+
--- a/README.md
+++ b/README.md
@ -0,0 +1,50 @@
+# pubsub - Publisher & Subscriber Package
+Publisher & Subscriber package as template package and source code.  
+
+Created for ROS Workshop 2020  
+Roverentwicklung für Explorationsaufgaben  
+Institute for Space Systems  
+University of Stuttgart.
+
+Created by Patrick Winterhalder,  
+[IRS](https://www.irs.uni-stuttgart.de/en/), University of Stuttgart.  
+  
+  
+  
+
+## Workshop Prerequisites
+* Install [Ubuntu 20.04]()
+* Install Visual Studio Code using [Ubuntu Software](https://wiki.ubuntuusers.de/Ubuntu_Software/)
+* Install [Git](https://linuxconfig.org/how-to-install-git-on-ubuntu-20-04-lts-focal-fossa-linux) (no account required yet)
+* Install [ROS2](https://index.ros.org/doc/ros2/Installation/Foxy/Linux-Install-Debians/) ("desktop" on PC, "base" on Raspberry Pi). Do install _argcomplete_, no need for _ROS 1 bridge_ or _RMW implementations_.
+* Install and update _rosdep_:
+  * `sudo apt install python3-rosdep2 -y`
+  * `rosdep update`
+  * (`sudo rosdep init`)
+* Work through ["Beginner: CLI Tools"](https://index.ros.org/doc/ros2/Tutorials/) tutorial
+  * [Configuring your ROS 2 environment](https://index.ros.org/doc/ros2/Tutorials/Configuring-ROS2-Environment/):
+    * Source setup files (underlay, overlay)
+    * Configure .bashrc (shell startup script)
+    * Add colcon_cd to .bashrc (shell startup script)
+    * Check environment variables (check for correct installation)
+    * Configure ROS_DOMAIN_ID (DDS Network Number)
+  * Cover turtlesim, rqt, topics, services, actions
+
+## Install Instructions
+* Move to colcon workspace: `cd <workspace_path>`
+* Clone repository: `git clone git://github.com/patrickw135/pubsub.git .` (include the . at the end)
+* Build workspace: `colcon build`  
+__Note:__ Only the files inside _src/_ are of importance.
+* Remember to run `source ~/<workspace_path>/install/local_setup.sh` after every build. Best would be to [add this command to _.bashrc_](https://github.com/patrickw135/pubsub/blob/master/bashrc_addons.txt) which is run everytime you start a new console.
+
+
+## During Workshop
+* Create workspace:
+  * Install [_colcon_](https://index.ros.org/doc/ros2/Tutorials/Colcon-Tutorial/#colcon): `sudo apt install python3-colcon-common-extensions -y`
+* Create packag inside _~/{workspace_name}/src_:
+  * `ros2 pkg create --build-type [ament_cmake, ament-python] <package_name>`
+  * Go back up one layer: `cd ..`
+  * Build workspace: `colcon build --symlink-install`
+* Add [this](https://github.com/patrickw135/pubsub/blob/main/bashrc_addons.txt) to end of .bashrc (`sudo nano .bashrc`), find all instances of "`~/ws_overlay_foxy`" and replace it with your local path to your colcon workspace  
+* [Instruction](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md) on how to create a custom message to interface between nodes
+
--- a/bashrc_addons.bash
+++ b/bashrc_addons.bash
@ -0,0 +1,73 @@
+# Add these lines to .bashrc, do this:
+# Add the the following in between "#----" to the end of your .bashrc script
+
+# To do this open .bashrc:
+# sudo nano ~/.bashrc
+
+# Move to end of .bashrc (arrow down)
+# Highlight the lines below and copy (Ctrl+C)
+# Paste into console at the end of .bashrc (Right click, paste or CTRL+LShift+V)
+
+
+
+#----------------------------------------------------------------------------------
+# ROS 2 SETUP
+echo "ROS 2 Setup:"
+
+# Source Underlay
+cmd="/opt/ros/foxy/setup.bash"
+source $cmd
+echo "ROS Underlay:       "$cmd
+
+# Source Overlay
+# Change to the path of your workspace's "install/local_setup.bash" file
+cmd="$HOME/colcon_ws/install/local_setup.bash"
+source $cmd
+echo "ROS Overlay:        "$cmd
+
+# You can add other workspaces
+#cmd="$HOME/colcon_libs/install/local_setup.bash"
+#source $cmd
+#echo "ROS Overlay:        "$cmd
+echo "******************************************************"
+
+# ROS 2 Settings
+# Print ROS Variables
+#printenv | grep -i ROS
+echo "ROS_VERSION:        "$ROS_VERSION
+echo "ROS_PYTHON_VERSION: "$ROS_PYTHON_VERSION
+echo "ROS_DISTRO:         "$ROS_DISTRO
+echo "******************************************************"
+
+# Define DDS Channel
+# (this is the channel your ROS system communicates at over your local network)
+# To change the channel open the ROS Underlay setup file:
+# sudo nano /opt/ros/foxy/setup.bash
+# Here, add the following command
+# export ROS_DOMAIN_ID=<your_channel_nr>
+# eg.: export ROS_DOMAIN_ID=69
+# Important: no spaces before and after "=" (in bash)
+
+# Print DDS Settings
+echo "ROS 2 DDS Settings:"
+export ROS_DOMAIN_ID=69
+echo "ROS_DOMAIN_ID:      "$ROS_DOMAIN_ID
+echo "To change:          sudo nano /opt/ros/foxy/setup.bash"
+echo "******************************************************"
+
+# Source colcon directory jump:
+#source /usr/share/colcon_cd/function/colcon_cd.sh
+#export _colcon_cd_root=~/colcon_ws
+
+# Print active Node & Topics
+echo "ROS 2 Topics active:"
+ros2 topic list
+echo "******************************************************"
+#echo "ROS 2 Nodes active:"
+#ros2 node list
+echo "******************************************************"
+printf "\n"
+echo "If your package is not listed (ros2 pkg list):"
+echo " * make sure you are sourcing the correct workspace: .bashrc"
+echo " * delete build/, install/ and rebuild w/o errors"
+#----------------------------------------------------------------------------------
--- a/instructions_custom_topics.md
+++ b/instructions_custom_topics.md
@ -0,0 +1,186 @@
+# How to create custom ROS topics
+This is a short instruction on how to create custom interfaces using ROS topics.  
+
+For this at least two packages will be required:
+* The python package contains your scripts (eg. ROS nodes)
+* The CMake package contains the custom msg/srv/act files  
+
+The CMake package is required because the custom msg/srv/act files cannot be created inside the python package as this is not supported yet.  
+
+__Table of Content__  
+* [CMake Package (eg. /pubsub_msg)](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#cmake-package-eg-pubsub_msg)  
+  * [Create CMake Package](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#1-create-cmake-package)
+  * [Create Message Files](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#2-create-message-files)
+  * [Configure CMakeLists.txt](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#3-configure-cmakeliststxt)
+  * [Configure package.xml](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#4-configure-packagexml)
+  * [Build Package](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#5-build-package)
+  * [Source newly built workspace](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#6-source-newly-built-workspace)
+  * [Check functionality](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#7-check-functionality)
+* [Python Package (eg. /pubsub)](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#python-package-eg-pubsub)
+  * [Create Python Package](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#1-create-python-package)
+  * [Write Python Scripts](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#2-write-python-scripts)
+  * [Configure package.xml](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#3-configure-packagexml)
+  * [Build Package](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#4-build-package)
+  * [Source newly built workspace](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#5-source-newly-built-workspace)
+  * [Run scripts](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#6-run-scripts)
+* [Sources](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#sources)
+
+
+
+
+
+
+
+## CMake Package (eg. /pubsub_msg)
+This package makes up the basis for custom ROS interfaces and contains all custom msg/srv/act files. Additionally, the special files (_CMakeLists.txt_ and _package.xml_) describe how these interface files are to be used.  
+
+This package must be created as a CMake package: `ros2 pkg create --build-type ament-cmake <package_name>`  
+
+This will result in an empty package structure:
+* msg/srv/act directory:
+  * This directory contains the custom msg files (eg. CustomMsg1.msg)
+* CMakeLists.txt:
+  * This file describes how to build this package
+  * Configure this file according to this [instruction](https://index.ros.org/doc/ros2/Tutorials/Custom-ROS2-Interfaces/#cmakelists-txt)
+* package.xml:
+  * This file contains meta information about this package
+  * Configure this file according to this [instruction](https://index.ros.org/doc/ros2/Tutorials/Custom-ROS2-Interfaces/#package-xml)
+
+
+### 1. Create CMake Package
+* Move to your colcon workspace's src directory: `cd <workspace_path>/src`
+* (For example: `cd ~/colcon_ws/src`)
+* Create CMake package: `ros2 pkg create --build-type ament_cmake <package_name>
+* (Here: `ros2 pkg create --build-type ament_cmake pubsub_msg`)
+
+
+### 2. Create Message Files
+* If not already available create msg directory inside package directory.  
+Resulting structure: <workspace_name>/src/<package_name>/msg
+* Move to newly created msg direcrory
+* Create your own custom message files, eg. _CustomMsg1.msg_.  
+Give your files comprehensible names, eg. _Epossetvalues.msg_
+
+
+### 3. Configure CMakeLists.txt
+Open CMakeLists.txt and ad these lines before `if(BUILD_TESTING)`:  
+`find_package(builtin_interfaces REQUIRED)`  
+`find_package(rosidl_default_generators REQUIRED)`  
+`find_package(std_msgs REQUIRED)`  
+`find_package(rclcpp REQUIRED)`  
+Then also add custom lines depending your package, here the custom message/service files are added:  
+`rosidl_generate_interfaces(${PROJECT_NAME}`  
+ `  "msg/CustomMsg1.msg"`  
+ `  "msg/CustomMsg2.msg"`  
+ `  DEPENDENCIES builtin_interfaces`  
+ ` )`
+
+### 4. Configure package.xml
+In order to let the build system know what this package depends on add these lines to _package.xml_:  
+```xml
+   <!-- ADD THESE LINES: START HERE -->
+   <build_depend>builtin_interfaces</build_depend>
+   <build_depend>rosidl_default_generators</build_depend>
+   <exec_depend>builtin_interfaces</exec_depend>
+   <exec_depend>rosidl_default_runtime</exec_depend>
+   <member_of_group>rosidl_interface_packages</member_of_group>
+   <!-- END HERE -->
+```
+
+### 5. Build Package
+* Move back to the workspace's most top layer: `cd ~/<workspace_path>`
+* Build workspace: `colcon build`
+* Sucessful response:  
+_Starting >>> pubsub  
+Starting >>> pubsub_msg  
+Finished <<< pubsub [0.85s]                                              
+Finished <<< pubsub_msg [1.09s]  
+Summary: 2 packages finished [1.56s]_
+
+
+### 6. Source newly built workspace
+* Run: `source ~/<workspace_path>/install/local_setup.bash`
+* If you already [updated your .bashrc file](https://github.com/patrickw135/pubsub/blob/master/bashrc_addons.txt) you can close all open consoles and start a new console (Ctrl+Alt+T). This will source your workspace automatically, as .bashrc is run every time you start a console.  
+__Important__: If you use multiple workspaces make sure you have the wanted workspace defined in .bashrc! Otherwise the changes introduced when building will not be available.
+
+
+### 7. Check functionality
+Check functionality of your messages by creataing a topic using your newly created message:  
+* CustomMsg1:  
+`ros2 topic pub /chatter1 pubsub_msg/CustomMsg1 "{temperature: {24.1234, 25.9876}, pressure: {1012.556, 1013.987}, humidity: {0.002, 0.001}}" --rate 1`
+* Response:  
+_publisher: beginning loop  
+publishing #1: pubsub_msg.msg.CustomMsg1(temperature=[24.12339973449707, 25.987600326538086], pressure=[1012.5560302734375, 1013.9869995117188], humidity=[0.0020000000949949026, 0.0010000000474974513])..._  
+
+* CustomMsg2:  
+`ros2 topic pub /chatter2 pubsub_msg/CustomMsg2 "{pitch_ctrl: 33.33, yaw_ctrl: 0.5}" --rate 1`
+* Response:  
+_publisher: beginning loop  
+publishing #1: pubsub_msg.msg.CustomMsg2(pitch_ctrl=33.33, yaw_ctrl=0.5)..._
+
+
+
+
+
+## Python Package (eg. /pubsub)
+This package contains your scripts, programs and libraries. After building the workspace (`colcon build`) the custom messages are available to all other packages.  
+
+This package can be created as a CMake (C++) package or as a python package depending on your coding preference.
+* C++:    `ros2 pkg create --build-type ament-cmake <package_name>`
+* Python: `ros2 pkg create --build-type ament-python <package_name>`  
+
+
+<package_name> directory:
+* This directory contains your python scripts (eg. listener.py)
+* Also place the non-standard libraries in this directory and import the library in your python scripts
+
+
+### 1. Create Python Package
+* Move to your workspace's source directory: `cd <workspace_path>/src`
+* Create python package: `rps2 pkg create --build-type ament_python <pkg_name>`
+
+### 2. Write Python Scripts
+When using custom interfaces in python scripts these must be imported into the python script first  
+```python
+from <package_name>.msg import <message_name>
+```
+replacing `<package_name>` with the package containing the custom message and `<message_name>` with the message file name (excluding the file ending .msg).  
+However, in order to be able to import the custom message types, `<message_name>` must first be known to the ROS system. This was established when creating the [CMake package](https://github.com/patrickw135/pubsub/blob/master/instructions_custom_topics.md#cmake-package-eg-pubsub_msg) containing the custom message. Additionally, you must add this dependency to the _package.xml_ of this package as stated in the next chapter.
+
+### 3. Configure package.xml
+In addition to importing the message type into your python script you must also configure _package.xml_ adding the package dependency of where you inherite the custom message from. Add this line to _package.xml_:  
+```xml
+   <depend>std_msgs</depend>
+   <!-- CUSTOM LINE -->
+   <!-- This is custom for the package you depend on -->
+   <exec_depend>package_name</exec_depend>
+```
+exchanging _package_name_ with the source package of the custom message type (here _pubsub_msg_), e.g.:  
+```xml
+   <depend>std_msgs</depend>
+   <!-- CUSTOM LINE -->
+   <!-- This is custom for the package you depend on -->
+   <exec_depend>pubsub_msg</exec_depend>
+```
+
+### 4. Build Package
+Now you can build the Python package.  
+* Move to your workspace's root: `cd ~/<workspace_path>`
+* Build workspace: `colcon build --symlink-install`
+
+### 5. Source newly built workspace
+* Run: `source ~/<workspace_path>/install/local_setup.bash`
+* If you already [updated your .bashrc file](https://github.com/patrickw135/pubsub/blob/master/bashrc_addons.txt) you can close all open consoles and start a new console (Ctrl+Alt+T). This will source your workspace automatically, as .bashrc is run every time you start a console.  
+__Important__: If you use multiple workspaces make sure you have the wanted workspace defined in .bashrc! Otherwise the changes introduced when building will not be available.
+
+### 6. Run scripts
+* Run Talker: `ros2 run pubsub talker`
+* Run Listener: `ros2 run pubsub listener`
+
+The talker console should print the sent data while the listener console should print the received data. These should match.
+
+If anything is unclear, compare this instruction material to the files in `/pubsub` and `/pubsub_msg`.  
+
+## Sources  
+[ROS2 Tutorial](https://index.ros.org/doc/ros2/Tutorials/Custom-ROS2-Interfaces/#creating-custom-ros-2-msg-and-srv-files)  
+[theconstructsim custom messages](https://www.theconstructsim.com/ros2-tutorials-7-how-to-create-a-ros2-custom-message-new/)  
--- a/rpi_install.bash
+++ b/rpi_install.bash
@ -0,0 +1,125 @@
+# Go through these bash commands one by one
+# Prerequisite is a fresh Ubuntu 20.04 !! 64bit !! OS
+# Only the password was changed after first boot
+# Everything else is stock
+
+# First Update
+sudo apt-get update && sudo apt-get upgrade -y && sudo apt-get dist-upgrade -y
+
+# Install ROS2 Foxy Fitzroy Desktop
+sudo apt update && sudo apt install locales
+sudo locale-gen en_US en_US.UTF-8
+sudo update-locale LC_ALL=en_US.UTF-8 LANG=en_US.UTF-8
+sudo apt update && sudo apt install -y curl gnupg2 lsb-release
+curl -s https://raw.githubusercontent.com/ros/rosdistro/master/ros.asc | sudo apt-key add -
+sudo sh -c 'echo "deb [arch=$(dpkg --print-architecture)] http://packages.ros.org/ros2/ubuntu $(lsb_release -cs) main" > /etc/apt/sources.list.d/ros2-latest.list'
+sudo apt update && sudo apt install -y ros-foxy-ros-base
+source /opt/ros/foxy/setup.bash
+# Check to see if installed correctly
+echo "ROS_VERSION:        "$ROS_VERSION
+
+
+# Install rosdep
+sudo apt install -y python3-rosdep2
+rosdep update
+
+
+# Install colcon
+sudo apt install -y python3-colcon-common-extensions
+
+
+# Install pip and  argcomplete
+sudo apt install -y python3-pip
+pip3 install -U argcomplete
+
+
+# in between
+sudo apt update && sudo apt upgrade -y
+
+
+# Create workspace
+mkdir -p ~/colcon_ws/src
+cd colcon_ws
+colcon build
+
+
+
+
+
+
+# Configure .bashrc:
+# The the following in between "#----" to the end of your .bashrc script
+#----------------------------------------------------------------------
+# ROS 2 SETUP
+echo "ROS 2 Setup:"
+
+# Source Underlay
+cmd="/opt/ros/foxy/setup.bash"
+source $cmd
+echo "ROS Underlay:       "$cmd
+
+# Source Overlay
+# Change to the path of your workspace's "install/local_setup.bash" file
+cmd="$HOME/colcon_ws/install/local_setup.bash"
+source $cmd
+echo "ROS Overlay:        "$cmd
+
+# You can add other workspaces
+#cmd="$HOME/colcon_libs/install/local_setup.bash"
+#source $cmd
+#echo "ROS Overlay:        "$cmd
+echo "******************************************************"
+
+# ROS 2 Settings
+# Print ROS Variables
+#printenv | grep -i ROS
+echo "ROS_VERSION:        "$ROS_VERSION
+echo "ROS_PYTHON_VERSION: "$ROS_PYTHON_VERSION
+echo "ROS_DISTRO:         "$ROS_DISTRO
+export ROS_DOMAIN_ID=69
+echo "ROS_DOMAIN_ID:      "$ROS_DOMAIN_ID
+echo "To change:          sudo nano /opt/ros/foxy/setup.bash"
+echo "******************************************************"
+echo "Topics active:"
+ros2 topic list
+echo "******************************************************"
+printf "\n"
+echo "If your package is not listed (ros2 pkg list):"
+echo " * make sure you are sourcing the correct workspace: .bashrc"
+echo " * delete build/, install/ and rebuild w/o errors"
+# Parsing of git branch
+parse_git_branch() {
+     git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/(\1)/'
+}
+export PS1="\u@\h \[\e[32m\]\w \[\e[91m\]\$(parse_git_branch)\[\e[00m\]$ "
+#----------------------------------------------------------------------
+
+
+
+
+
+
+# Install network tools
+sudo apt install -y wireless-tools
+
+
+# Install Git
+sudo apt install -y git
+
+# Setup remote git from inside workspace
+cd ~/colcon_ws
+git init
+git remote add origin https://github.com/patrickw135/pubsub.git
+git fetch --all
+git reset --hard origin/master
+
+
+# Install your project specific python packages
+# You can use pip3 as the install tool, eg:
+pip3 install picamera 
+# Or you can use the software installer:
+sudo apt install python3-picamera
+
+
+# again
+sudo apt update && sudo apt upgrade -y
--- a/src/pubsub/package.xml
+++ b/src/pubsub/package.xml
@ -0,0 +1,31 @@
+<?xml version="1.0"?>
+<?xml-model href="http://download.ros.org/schema/package_format3.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>
+<package format="3">
+  <name>pubsub</name>
+  <version>0.0.0</version>
+  <description>TODO: Package description</description>
+  <maintainer email="winterhalder.p@googlemail.com">patrick</maintainer>
+  <license>TODO: License declaration</license>
+
+  <!-- ADD THESE LINES -->
+  <!-- Package not listed when using this: <exec_depend>rclpy</exec_depend> -->
+  <!-- <exec_depend>std_msgs</exec_depend> -->
+  <!-- <build_depend>std_msgs</build_depend> -->
+  <depend>std_msgs</depend>
+  
+  <!-- CUSTOM LINE -->
+  <!-- This is custom for the package you depend on -->
+  <exec_depend>pubsub_msg</exec_depend>
+  <!-- END HERE -->
+  
+  
+
+  <test_depend>ament_copyright</test_depend>
+  <test_depend>ament_flake8</test_depend>
+  <test_depend>ament_pep257</test_depend>
+  <test_depend>python3-pytest</test_depend>
+
+  <export>
+    <build_type>ament_python</build_type>
+  </export>
+</package>
--- a/src/pubsub/pubsub/init.py
+++ b/src/pubsub/pubsub/init.py
--- a/src/pubsub/pubsub/listener.py
+++ b/src/pubsub/pubsub/listener.py
@ -0,0 +1,83 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+#********************************************#
+# Listener Template
+
+# Creted for:
+# ROS2 Workshop 2020
+# Roverentwicklung für Explorationsaufgaben
+# Institute for Space Systems
+# University of Stuttgart
+
+# Created by Patrick Winterhalder
+# IRS, University of Stuttgart
+#********************************************#
+
+import rclpy
+from rclpy.node import Node
+
+# Import Subscriber Library
+from .pubsub_library import CustomMsg1_sub
+from .pubsub_library import CustomMsg2_sub
+
+# Import Message Types
+from pubsub_msg.msg import CustomMsg1
+from pubsub_msg.msg import CustomMsg2
+
+
+def main(args=None):
+    rclpy.init(args=args)
+
+    # Start nodes here, should create object <node_name> for every node
+    listener_1 = CustomMsg1_sub(NODE_NAME="pubsub_listener_1", TOPIC_NAME="/chatter1",MSG_TYPE=CustomMsg1, NUM_MSGS=0)
+    listener_2 = CustomMsg2_sub(NODE_NAME="pubsub_listener_2", TOPIC_NAME="/chatter2",MSG_TYPE=CustomMsg2, NUM_MSGS=0)
+
+
+    while rclpy.ok():
+        try:
+            # Insert main looping script here...
+
+            # Receive Topics by running nodes
+            rclpy.spin_once(listener_1, timeout_sec=0.01)
+            rclpy.spin_once(listener_2, timeout_sec=0.01)
+
+            # Do sth if message was received
+            if listener_1.topic_received is True:
+                listener_1.topic_received = False # zurücksetzen
+                msg_1 = listener_1.return_msg()
+                #*********************************
+                # Do sth based on received message
+                #*********************************
+            if listener_2.topic_received is True:
+                listener_2.topic_received = False # zurücksetzen
+                msg_2 = listener_2.return_msg()
+                #*********************************
+                # Do sth based on received message
+                #*********************************
+            
+
+            # Check if "msg_1" or "msg_2" is available as a local variable
+            if 'msg_1' in locals():
+                # Print msg_1
+                listener_1.print_msg()
+            if 'msg_2' in locals():
+                # Print msg_2
+                listener_2.print_msg()
+
+            # Here, you can now also publish/pass on the results of this script by
+            # using the "MinimalPublisher" class. For this please  refer to "talker.py".
+
+        except (KeyboardInterrupt, SystemExit):
+            print("\n\nShutting down...")
+
+            # Insert "<node_name>.destroy_node()" here for all running nodes in this script
+            # eg:
+            listener_1.destroy_node()
+            listener_2.destroy_node()
+            rclpy.shutdown()
+        
+
+
+if __name__ == '__main__':
+    main()
--- a/src/pubsub/pubsub/pubsub_library.py
+++ b/src/pubsub/pubsub/pubsub_library.py
@ -0,0 +1,284 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+#********************************************#
+# Publisher/Subscriber Class Library
+
+# Creted for:
+# ROS2 Workshop 2020
+# Roverentwicklung für Explorationsaufgaben
+# Institute for Space Systems
+# University of Stuttgart
+
+# Created by Patrick Winterhalder
+# IRS, University of Stuttgart
+#********************************************#
+
+import rclpy
+from rclpy.node import Node
+
+# How to use:
+# from pubsub_library import MinimalPublisher
+# from pubsub_library import MinimalSubscriber
+# minimal_publisher = MinimalPublisher(NODE_NAME='minimal_pub', TOPIC_NAME='user_controller', MSG_TYPE=Usercontroller, MSG_PERIOD=0.5)
+# minimal_subscriber = MinimalSubscriber(NODE_NAME='minimal_sub', TOPIC_NAME='epos_feedback', MSG_TYPE=Eposreturn)
+# See --> talker.py, listener.py
+
+
+
+#******************************************************************************#
+# Definition of Parent Classes
+
+class MinimalPublisher(Node):
+
+    def __init__(self, NODE_NAME, TOPIC_NAME, MSG_TYPE, MSG_PERIOD):
+        self.PUBLISHER_NAME= NODE_NAME
+        self.TOPIC_NAME = TOPIC_NAME
+        self.CUSTOM_MSG = MSG_TYPE
+        self.timer_period = MSG_PERIOD  # [seconds]
+        # Init above laying class Node
+        super().__init__(self.PUBLISHER_NAME)
+        print("\t- " + str(TOPIC_NAME) + "\n")
+        self.publisher_ = self.create_publisher(
+            self.CUSTOM_MSG, 
+            self.TOPIC_NAME, 
+            10)
+        self.new_msg = False
+        # Define Node Frequency, equivalent to ~rospy.rate()
+        self.timer = self.create_timer(self.timer_period, self.publisher_timer)
+        return
+
+    def publisher_timer(self):
+        if self.new_msg is True:
+            try:
+                #self.get_logger().info('Pub:')
+                self.publisher_.publish(self.msg)
+                self.new_msg = False
+            except TypeError:
+                print("[ERROR] Msg-Data-Types do not match")
+        return
+
+    # Publish using Timer
+    def timer_publish(self, msg):
+        self.msg=msg
+        self.new_msg = True
+        return
+
+    # Publish directly without Timer
+    def direct_publish(self, msg):
+        try:
+            #self.get_logger().info('Pub:')
+            self.publisher_.publish(msg)
+        except TypeError:
+            print("[ERROR] Msg-Data-Types do not match")
+        return
+
+
+
+
+
+
+
+
+
+class MinimalSubscriber(Node):
+
+    def __init__(self, NODE_NAME, TOPIC_NAME, MSG_TYPE, NUM_MSGS):
+        self.NODE_NAME= NODE_NAME
+        self.TOPIC_NAME = TOPIC_NAME
+        self.CUSTOM_MSG = MSG_TYPE
+        self.NUM_MSGS = NUM_MSGS
+        self.topic_received = False
+        # Init above laying class Node
+        super().__init__(self.NODE_NAME)
+        self.subscription = self.create_subscription(
+            self.CUSTOM_MSG,            # Message Type
+            self.TOPIC_NAME,            # Topic Name
+            self.listener_callback,     # Callback Function
+            self.NUM_MSGS)              # List of saved messages
+        self.subscription  # prevent unused variable warning
+        return
+
+    def listener_callback(self, msg):
+        self.get_logger().info('I heard: "%s"' % msg.data)
+        return
+
+
+
+
+
+
+
+
+
+
+#***************************************************************************#
+# Child Classes inherite through super().__init__(...) from parent class
+# Child's purpose is to simplify subscribing to custom messages 
+# For this to work you must customize "listener_callback", "return_msg" (and "print_msg")
+
+
+
+# Exemplary Subscriber Class: Inheriting from MinimalSubscriber Class
+# This class is custom made for receiving the specific msg type but uses MinimalSubscriber as foundation
+# Create a new class of this type for every custom msg you want to receive, customizing the listener_callback, 
+# return_msg (and print_msg) functions to correspond to your message
+
+class example_subscriber(MinimalSubscriber):
+
+    def __init__(self, NODE_NAME, TOPIC_NAME, MSG_TYPE, NUM_MSGS):
+        # Init MinimalSubscriber:
+        super().__init__(NODE_NAME, TOPIC_NAME, MSG_TYPE, NUM_MSGS)
+        print("\t- " + str(TOPIC_NAME))
+        # !!! CUSTOMIZE THESE VARIABLES TO WORK WITH YOUR MESSAGE FILE !!!
+        self.pos_actual = None
+        self.vel_actual = None
+        self.baffle_switch = None
+        self.current = None
+        self.temp = None
+    
+
+    # !!! CUSTOMIZE THIS FUNCTION TO WORK WITH YOUR MESSAGE FILE !!!
+    def listener_callback(self, msg): # Overwrites callback from inherited class
+        self.topic_received = True
+        self.pos_actual = msg.pos_actual
+        self.vel_actual = msg.vel_actual
+        self.baffle_switch = msg.baffle_switch
+        self.current = msg.epos_current
+        self.temp = msg.epos_temp
+        #print_msg(self) # activate to print the received data --> customize print_msg(self) !
+        return
+
+    # !!! CUSTOMIZE THIS FUNCTION TO WORK WITH YOUR MESSAGE FILE !!!
+    def return_msg(self): # Extract only msg variables from "self" object
+        msg = self.CUSTOM_MSG()
+        msg.pos_actual = self.pos_actual
+        msg.vel_actual = self.vel_actual
+        msg.baffle_switch = self.baffle_switch
+        msg.epos_current = self.current
+        msg.epos_temp = self.temp
+        return msg
+
+    # !!! CUSTOMIZE THIS FUNCTION TO WORK WITH YOUR MESSAGE FILE !!! (optional)
+    def print_msg(self):
+        print("[SUBSCRIBER] %s received topic:\t/%s" %(self.NODE_NAME, self.TOPIC_NAME))
+        string = "Received:\t"
+
+        # Check length of all transmitted value lists to be equal (equal number of parameters)
+        length = len(self.pos_actual)
+        if any(len(lst) != length for lst in [self.vel_actual, self.current, self.temp]):
+            print("[TRANSMISSION ERROR] Length of lists inside topic %s do not match" %(self.TOPIC_NAME))
+        else:
+            complete_list = []
+            complete_list.append(self.pos_actual)
+            complete_list.append(self.vel_actual)
+            complete_list.append(self.current)
+            complete_list.append(self.temp)
+            #print(complete_list)
+            for i in range(len(complete_list)):
+                for y in range(len(complete_list[0])):
+                    string += "%.2f,\t" %(complete_list[i][y])
+            string += str(self.baffle_switch)
+            print(string)
+        return
+
+
+#************************************************************************************#
+# CustomMsg1 Subscriber Class
+class CustomMsg1_sub(MinimalSubscriber):
+
+    def __init__(self, NODE_NAME, TOPIC_NAME, MSG_TYPE, NUM_MSGS):
+        # Init MinimalSubscriber:
+        super().__init__(NODE_NAME, TOPIC_NAME, MSG_TYPE, NUM_MSGS)
+        print("\t- " + str(TOPIC_NAME))
+        # CustomMsg1 Variables
+        self.temperature = None
+        self.pressure = None
+        self.humidity = None
+        return
+    
+
+    # !!! CUSTOMIZE THIS FUNCTION TO WORK WITH YOUR MESSAGE FILE !!!
+    def listener_callback(self, msg): # Overwrites callback from inherited class
+        self.topic_received = True
+        self.temperature = msg.temperature
+        self.pressure = msg.pressure
+        self.humidity = msg.humidity
+        #print_msg(self) # activate to print the received data --> customize print_msg(self) !
+        return
+
+    # !!! CUSTOMIZE THIS FUNCTION TO WORK WITH YOUR MESSAGE FILE !!!
+    def return_msg(self): # Extract only msg variables from "self" object
+        msg = self.CUSTOM_MSG()
+        msg.temperature = self.temperature
+        msg.pressure = self.pressure
+        msg.humidity = self.humidity
+        return msg
+
+    # !!! CUSTOMIZE THIS FUNCTION TO WORK WITH YOUR MESSAGE FILE !!! (optional)
+    def print_msg(self):
+        print("[SUBSCRIBER] %s received topic:\t/%s" %(self.NODE_NAME, self.TOPIC_NAME))
+        string = "Received:\t"
+
+        # Check length of all transmitted value lists to be equal (equal number of parameters)
+        length = len(self.temperature)
+        if any(len(lst) != length for lst in [self.temperature, self.pressure, self.humidity]):
+            print("[TRANSMISSION ERROR] Length of lists inside topic %s do not match" %(self.TOPIC_NAME))
+        else:
+            complete_list = []
+            complete_list.append(self.temperature)
+            complete_list.append(self.pressure)
+            complete_list.append(self.humidity)
+            #print(complete_list)
+            for i in range(len(complete_list)):
+                for y in range(len(complete_list[0])):
+                    string += "%.2f,\t" %(complete_list[i][y])
+            print(string)
+        return
+
+
+
+#************************************************************************************#
+# CustomMsg2 Subscriber Class
+class CustomMsg2_sub(MinimalSubscriber):
+
+    def __init__(self, NODE_NAME, TOPIC_NAME, MSG_TYPE, NUM_MSGS):
+        # Init MinimalSubscriber:
+        super().__init__(NODE_NAME, TOPIC_NAME, MSG_TYPE, NUM_MSGS)
+        print("\t- " + str(TOPIC_NAME))
+        # CustomMsg1 Variables
+        self.pitch_ctrl = None
+        self.yaw_ctrl = None
+        return
+    
+
+    # !!! CUSTOMIZE THIS FUNCTION TO WORK WITH YOUR MESSAGE FILE !!!
+    def listener_callback(self, msg): # Overwrites callback from inherited class
+        self.topic_received = True
+        self.pitch_ctrl = msg.pitch_ctrl
+        self.yaw_ctrl = msg.yaw_ctrl
+        #print_msg(self) # activate to print the received data --> customize print_msg(self) !
+        return
+
+    # !!! CUSTOMIZE THIS FUNCTION TO WORK WITH YOUR MESSAGE FILE !!!
+    def return_msg(self): # Extract only msg variables from "self" object
+        msg = self.CUSTOM_MSG()
+        msg.pitch_ctrl = self.pitch_ctrl
+        msg.yaw_ctrl = self.yaw_ctrl
+        return msg
+
+    # !!! CUSTOMIZE THIS FUNCTION TO WORK WITH YOUR MESSAGE FILE !!! (optional)
+    def print_msg(self):
+        print("[SUBSCRIBER] %s received topic:\t/%s" %(self.NODE_NAME, self.TOPIC_NAME))
+        string = "Received:\t"
+
+        # Check length of all transmitted value lists to be equal (equal number of parameters)
+        complete_list = []
+        complete_list.append([self.pitch_ctrl])
+        complete_list.append([self.yaw_ctrl])
+        #print(complete_list)
+        for i in range(len(complete_list)):
+            for y in range(len(complete_list[0])):
+                string += "%.2f,\t" %(complete_list[i][y])
+        print(string)
+        return
--- a/src/pubsub/pubsub/talker.py
+++ b/src/pubsub/pubsub/talker.py
@ -0,0 +1,69 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+#********************************************#
+# Talker Template
+
+# Creted for:
+# ROS2 Workshop 2020
+# Roverentwicklung für Explorationsaufgaben
+# Institute for Space Systems
+# University of Stuttgart
+
+# Created by Patrick Winterhalder
+# IRS, University of Stuttgart
+#********************************************#
+
+import rclpy
+from rclpy.node import Node
+
+# Import Publisher Library (Python Library)
+from .pubsub_library import MinimalPublisher
+
+# Import Message Types (Message Files)
+from pubsub_msg.msg import CustomMsg1
+from pubsub_msg.msg import CustomMsg2
+
+
+def main(args=None):
+    rclpy.init(args=args)
+
+    # Start nodes here, should create object <node_name> for every node
+    talker_1 = MinimalPublisher(NODE_NAME="pubsub_talker_1", TOPIC_NAME="/chatter1", MSG_TYPE=CustomMsg1, MSG_PERIOD=0.25)
+    talker_2 = MinimalPublisher(NODE_NAME="pubsub_talker_2", TOPIC_NAME="/chatter2", MSG_TYPE=CustomMsg2, MSG_PERIOD=0.5)
+
+    while rclpy.ok():
+        try:
+            # Insert main looping script here...
+
+            # Eg. create custom msgs, fill and send them
+            # CustomMsg1 to talker_1
+            msg_1 = CustomMsg1()
+            msg_1.temperature = [24.5, 25.5, 26.5]
+            msg_1.pressure = [1011.5, 1012.55, 1010.11]
+            msg_1._humidity = [0.002, 0.0019, 0.0021]
+            talker_1.timer_publish(msg_1)
+
+            # CustomMsg2 to talker_2
+            msg_2 = CustomMsg2()
+            msg_2.pitch_ctrl = 0.0
+            msg_2.yaw_ctrl = 0.22
+            talker_2.timer_publish(msg_2)
+
+
+            # Insert "rclpy.spin_once(<node_name>, timeout_sec=0.1)" at the end of 
+            # "try" for every node running in this script
+            rclpy.spin_once(talker_1, timeout_sec=0.1)
+            rclpy.spin_once(talker_2, timeout_sec=0.1)
+            
+        except (KeyboardInterrupt, SystemExit):
+            print("\n\nShutting down...")
+            # Insert "<node_name>.destroy_node()" here once for every node running in this script
+            talker_1.destroy_node()
+            talker_2.destroy_node()
+            rclpy.shutdown()
+        
+
+
+if __name__ == '__main__':
+    main()
--- a/src/pubsub/resource/pubsub
+++ b/src/pubsub/resource/pubsub
--- a/src/pubsub/setup.cfg
+++ b/src/pubsub/setup.cfg
@ -0,0 +1,4 @@
+[develop]
+script-dir=$base/lib/pubsub
+[install]
+install-scripts=$base/lib/pubsub
--- a/src/pubsub/setup.py
+++ b/src/pubsub/setup.py
@ -0,0 +1,27 @@
+from setuptools import setup
+
+package_name = 'pubsub'
+
+setup(
+    name=package_name,
+    version='0.0.0',
+    packages=[package_name],
+    data_files=[
+        ('share/ament_index/resource_index/packages',
+            ['resource/' + package_name]),
+        ('share/' + package_name, ['package.xml']),
+    ],
+    install_requires=['setuptools'],
+    zip_safe=True,
+    maintainer='patrick',
+    maintainer_email='winterhalder.p@googlemail.com',
+    description='TODO: Package description',
+    license='TODO: License declaration',
+    tests_require=['pytest'],
+    entry_points={
+        'console_scripts': [
+            'talker = pubsub.talker:main',
+            'listener = pubsub.listener:main'
+        ],
+    },
+)
--- a/src/pubsub/test/test_copyright.py
+++ b/src/pubsub/test/test_copyright.py
@ -0,0 +1,23 @@
+# Copyright 2015 Open Source Robotics Foundation, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from ament_copyright.main import main
+import pytest
+
+
+@pytest.mark.copyright
+@pytest.mark.linter
+def test_copyright():
+    rc = main(argv=['.', 'test'])
+    assert rc == 0, 'Found errors'
--- a/src/pubsub/test/test_flake8.py
+++ b/src/pubsub/test/test_flake8.py
@ -0,0 +1,25 @@
+# Copyright 2017 Open Source Robotics Foundation, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from ament_flake8.main import main_with_errors
+import pytest
+
+
+@pytest.mark.flake8
+@pytest.mark.linter
+def test_flake8():
+    rc, errors = main_with_errors(argv=[])
+    assert rc == 0, \
+        'Found %d code style errors / warnings:\n' % len(errors) + \
+        '\n'.join(errors)
--- a/src/pubsub/test/test_pep257.py
+++ b/src/pubsub/test/test_pep257.py
@ -0,0 +1,23 @@
+# Copyright 2015 Open Source Robotics Foundation, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from ament_pep257.main import main
+import pytest
+
+
+@pytest.mark.linter
+@pytest.mark.pep257
+def test_pep257():
+    rc = main(argv=['.', 'test'])
+    assert rc == 0, 'Found code style errors / warnings'
--- a/src/pubsub_msg/CMakeLists.txt
+++ b/src/pubsub_msg/CMakeLists.txt
@ -0,0 +1,59 @@
+cmake_minimum_required(VERSION 3.5)
+project(pubsub_msg)
+
+# Default to C99
+if(NOT CMAKE_C_STANDARD)
+  set(CMAKE_C_STANDARD 99)
+endif()
+
+# Default to C++14
+if(NOT CMAKE_CXX_STANDARD)
+  set(CMAKE_CXX_STANDARD 14)
+endif()
+
+if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+  add_compile_options(-Wall -Wextra -Wpedantic)
+endif()
+
+# find dependencies
+find_package(ament_cmake REQUIRED)
+# uncomment the following section in order to fill in
+# further dependencies manually.
+# find_package(<dependency> REQUIRED)
+
+
+
+
+# -->
+# ADD THESE LINES: START HERE
+
+find_package(builtin_interfaces REQUIRED)
+find_package(rosidl_default_generators REQUIRED)
+find_package(std_msgs REQUIRED)
+find_package(rclcpp REQUIRED)
+
+# CUSTOM LINES: CHANGE FOR YOUR FILENAMES
+rosidl_generate_interfaces(${PROJECT_NAME}
+  "msg/CustomMsg1.msg"
+  "msg/CustomMsg2.msg"
+  DEPENDENCIES builtin_interfaces
+ )
+
+# END HERE 
+# <--
+
+
+
+
+if(BUILD_TESTING)
+  find_package(ament_lint_auto REQUIRED)
+  # the following line skips the linter which checks for copyrights
+  # uncomment the line when a copyright and license is not present in all source files
+  #set(ament_cmake_copyright_FOUND TRUE)
+  # the following line skips cpplint (only works in a git repo)
+  # uncomment the line when this package is not in a git repo
+  #set(ament_cmake_cpplint_FOUND TRUE)
+  ament_lint_auto_find_test_dependencies()
+endif()
+
+ament_package()
--- a/src/pubsub_msg/msg/CustomMsg1.msg
+++ b/src/pubsub_msg/msg/CustomMsg1.msg
@ -0,0 +1,8 @@
+# Header data, eg timestamp
+# Problem: "header__struct.hpp: No such file or directory"
+#Header header
+
+# Sensor Data coming back from an array of atmospheric sensors
+float32[] temperature
+float32[] pressure
+float32[] humidity
--- a/src/pubsub_msg/msg/CustomMsg2.msg
+++ b/src/pubsub_msg/msg/CustomMsg2.msg
@ -0,0 +1,7 @@
+# Header data, eg timestamp
+# Problem: "header__struct.hpp: No such file or directory"
+#Header header
+
+# User inputs, eg. for controlling a camera mast , eg. set angles [rad]
+float32 pitch_ctrl
+float32 yaw_ctrl
--- a/src/pubsub_msg/package.xml
+++ b/src/pubsub_msg/package.xml
@ -0,0 +1,34 @@
+<?xml version="1.0"?>
+<?xml-model href="http://download.ros.org/schema/package_format3.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>
+<package format="3">
+  <name>pubsub_msg</name>
+  <version>0.0.0</version>
+  <description>TODO: Package description</description>
+  <maintainer email="winterhalder.p@googlemail.com">patrick</maintainer>
+  <license>TODO: License declaration</license>
+
+  <buildtool_depend>ament_cmake</buildtool_depend>
+  <test_depend>ament_lint_auto</test_depend>
+  <test_depend>ament_lint_common</test_depend>
+
+
+
+
+  <!-- ADD THESE LINES: START HERE -->
+  <build_depend>builtin_interfaces</build_depend>
+  <build_depend>rosidl_default_generators</build_depend>
+  
+  <exec_depend>builtin_interfaces</exec_depend>
+  <exec_depend>rosidl_default_runtime</exec_depend>
+  
+  <member_of_group>rosidl_interface_packages</member_of_group>
+  <!-- END HERE -->
+
+
+
+
+
+  <export>
+    <build_type>ament_cmake</build_type>
+  </export>
+</package>
--- a/workshopinstall.sh
+++ b/workshopinstall.sh
@ -0,0 +1,41 @@
+#!/bin/bash
+sudo apt-get update && sudo apt-get upgrade -y
+sudo apt-get dist-upgrade -y
+
+# Install Visual Studio Code
+sudo apt install -y software-properties-common apt-transport-https wget
+wget -q https://packages.microsoft.com/keys/microsoft.asc -O- | sudo apt-key add -
+sudo add-apt-repository "deb [arch=amd64] https://packages.microsoft.com/repos/vscode stable main"
+sudo apt update && sudo apt install -y code
+
+# Install Git
+sudo apt install -y git
+
+# Install ROS2 Foxy Fitzroy Desktop
+#sudo apt update && sudo apt install locales
+#sudo locale-gen en_US en_US.UTF-8
+#sudo update-locale LC_ALL=en_US.UTF-8 LANG=en_US.UTF-8
+sudo apt update && sudo apt install -y curl gnupg2 lsb-release
+curl -s https://raw.githubusercontent.com/ros/rosdistro/master/ros.asc | sudo apt-key add -
+sudo sh -c 'echo "deb [arch=$(dpkg --print-architecture)] http://packages.ros.org/ros2/ubuntu $(lsb_release -cs) main" > /etc/apt/sources.list.d/ros2-latest.list'
+sudo apt update && sudo apt install -y ros-foxy-desktop
+source /opt/ros/foxy/setup.bash
+
+# Install pip and  argcomplete
+sudo apt install -y python3-pip
+pip3 install -U argcomplete
+
+# If colcon does not build: Install pytest version>=5.0 ???
+
+# Install rosdep
+sudo apt install -y python3-rosdep2
+rosdep update
+
+# in between
+sudo apt update && sudo apt upgrade -y
+
+# Install colcon
+sudo apt install -y python3-colcon-common-extensions
+
+# At the end again
+sudo apt update && sudo apt upgrade -y