Building With the Bob Build Tool

Building With the Bob Build Tool#

This guide places the sources in the directory $HOME/projects/l4re. You can choose the this location as you like. That’s why we start defining an environment variable for this location:

export BOB_DIR=$HOME/projects/l4re

Prerequisites#

To build the pre-composed L4Re system configurations, Bob Build Tool is used as a meta build system. So first, we install Bob, preferably into a dedicated Python virtualenv e.g.:

cd $BOB_DIR
virtualenv bob-venv
. bob-venv/bin/activate
pip install BobBuildTool

Hint

Depending on your distribution, you may have to install python3-virtualenv or a similar package.

If we leave the shell, we only have to source bob-venv/bin/activate next time:

. bob-venv/bin/activate

Attention

It is highly recommended to apply the standard configuration before proceeding. It will save network bandwidth and reduce build times.

Next, we clone the L4Re tutorial recipes:

git clone https://github.com/l4re/l4re-tutorials.git

Lastly, we have to fetch the dependent layers:

cd l4re-tutorials
bob layers update

Hint

Layers usually only need to be fetched initially. Bob will update them automatically unless the --build-only / -b option is used. In this case it is recommended to update them explicitly after the tutorials repository has been pulled.

Build and run the “Hello World” example#

Now we can build L4Re with a single application: Hello World. The image is built for the Qemu x86 platform:

bob dev --dev-sandbox examples-amd64/examples::hello -j

This might take a while. Especially the task that builds core::l4re. But when finished, the output should end with the words Build result is in dev/dist/examples/hello/1/workspace.

Note

The --dev-sandbox option runs the build in a containerized environment for better reproducibility. If your system configuration prohibits the use of unprivileged containers, you can leave out the switch.

With -j all available CPU cores are used.

See the bob-dev manpage for more details.

To run the example, qemu-system-x86_64 must be installed. If in doubt, install the qemu-system package on your system (Debian/Ubuntu. Other distributions may have a similar package).

Finally, we can execute the runner script in the output folder:

dev/dist/examples/hello/1/workspace/bootx64.efi.launch

Continuing The Introduction Guide#

The steps to build the example also checked out the L4Re source code. Knowing the code location is essential for the next steps in this introductory guide. It might be handy to define the following additional environment variable:

export L4RE_SRCDIR=$(pwd)/dev/src/core/l4re/1/workspace

Now you can go to Modifying the Example Scenario to learn how to adjust l4re scenarios to your liking.

Contents