ROS2 build workspace

The workspace is the folder where you can build and install ROS2 packages.

Creating a workspace

A ROS2 workspace, in order to be built using the native Colcon build system must have the following structure.

.
└── src

The first step is the creation of such workspace.

$ mkdir -p  my_workspace/src

Place your source code inside the src directory.

For example, to create a symbolic link for the sources provided in this repository

$ cd my_workspace/src
$ ln -s ../../src/interfaces .
$ cd ..

Build the sources

$ colcon build

After you have built some sources, your workspace will look like this

.
├── build
├── install
├── log
└── src

The build directory will be where intermediate files are stored. For each package a subfolder will be created in which e.g. CMake is being invoked.
The install directory is where each package will be installed to. By default each package will be installed into a separate subdirectory.
The log directory contains various logging information about each colcon invocation.

To use the executables and libraries with the command line interface you need to source the install directory.

$ source install/setup.sh

If you do not want to build a specific package place an empty file named COLCON_IGNORE in the directory and it will not be indexed.
```
 $ touch src/ros2/rviz/COLCON_IGNORE
```
Colcon by default builds packages in parallel. This could cause unpredictable errors. To build sequentially add --executor sequential as parameter to colcon build.
Colcon by default installs each package in a separate subdirectory. To install all packages into a combined directory add --merge-install as parameter to colcon build.
If you want to avoid configuring and building tests in CMake packages add --cmake-args -DBUILD_TESTING=0 as parameter to colcon build.