opp_env is a powerful tool that allows for the easy and automated installation of OMNeT++ simulation frameworks and models, including dependencies like INET Framework and OMNeT++ itself. It can install any version of OMNeT++ and INET, as well as currently selected versions of Veins, SimuLTE, and Simu5G. We are working towards expanding its database with more models, and we are open to suggestions and contributions.

opp_env relies on Nix, a powerful package manager that provides isolation between different versions of dependencies and allows for reproducible builds. By leveraging the power of Nix, opp_env ensures that each installation is consistent and can be easily replicated on different machines.

opp_env supports Linux and macOS systems. On Windows 10 & 11, opp_env can be run on the Windows Subsystem for Linux (WSL2).

opp_env provides a number of powerful features that make it a valuable tool for any researcher or developer working with OMNeT++ simulation frameworks:

• Automated installation of OMNeT++ simulation frameworks and models, including dependencies like INET Framework and OMNeT++ itself.
• Support for any version of OMNeT++ and INET, as well as currently selected versions of Veins, SimuLTE, and Simu5G.
• Reproducible builds thanks to the powerful isolation provided by Nix.
• Easy to use shell command that sets up an environment for working with the selected simulation framework.
• Customizable configuration options that allow for advanced control over the installation process.

Using opp_env is simple. To install a specific version of a simulation framework and its dependencies, first create a workspace:

mkdir workspace
cd workspace
opp_env init

Then run the following command:

opp_env install <framework-version>

For example, to install Simu5G version 1.2.1, run the following command:

opp_env install simu5g-1.2.1

This will download Simu5G, the matching INET and OMNeT++ packages and compile them.

To open a shell prompt to use Simu5G, type:

opp_env shell simu5g-1.2.1

To see the list of available packages, type the following:

opp_env list

Installation is based on the pip install command. On some system, namely recent versions of Ubuntu / Debian, this command stops with an error message:

error: externally-managed-environment
[lengthy explanation]

To work around the error, follow the instructions in the printed message, which boils down to either adding the --break-system-packages option to the pip install commands, or setting up a Python virtual environment (venv) and working from there.

To get started with opp_env, you need to have Python3, pip and Nix installed on your machine. You can download and install Nix from here. All other opp_env dependencies are automatically installed using the Nix package manager.

Once you have the prerequisites, you can install opp_env using pip:

First, make sure that pip is the latest version:

pip install --upgrade pip

In the future, end users will be able to install opp_env using the following command:

pip install --user opp_env

For now, you can install directly from GitHub:

pip3 install --user git+https://github.com/omnetpp/opp_env.git

If you get the error: externally-managed-environment message, see the note marked IMPORTANT above.

When you install opp_env using pip, it installs the opp_env Python module, as well as a small script into your system's path (e.g. ~/.local/bin) that allows you to invoke it from the shell. The opp_env command is equivalent to running python -m opp_env, which also runs the opp_env Python module. (Make sure that ~/.local/bin is in your PATH environment variable.)

opp_env requires the Nix package manager which is available only on Linux and macOS, but you can still use opp_env on Windows running it in a WSL2 (Windows Subsystem for Linux) container.

For Windows 10 and 11, we provide a pre-packaged, Ubuntu 22.04 based WSL2 container with all the necessray dependencies (Python3, pip, Nix, etc.) instlled.

To install the opp_env WSL distro image, open a command prompt and run the following command:

curl.exe -L https://github.com/omnetpp/opp_env/releases/download/wsl/opp_env-wsl.tar.gz | wsl --import opp_env .\opp_env-wsl -

The above command will download and install a WSL2 container image for opp_env that can be started with:

wsl -d opp_env --cd ~

Once you are inside the container, you can run the opp_env command as suggested in the previous section.

We provide docker images for opp_env that can be installed with the following command:

docker pull ghcr.io/omnetpp/opp_env

You can try it interactively with:

docker run -it ghcr.io/omnetpp/opp_env

This image is the same as the one used for generating the WSL2 image.

If you want to contribute to the development of opp_env or need to modify the source code for any reason, you can install the package in editable mode by cloning the git repo, changing to its root directory and using the following command:

pip install --user --editable .

This will install the Python module and the opp_env command, but with the added ability to make local modifications that will take effect immediately.

If you get the error: externally-managed-environment message, see the note marked IMPORTANT above.

In case of other errors, try upgrading pip to the latest version first by running python3 -m pip install --upgrade pip.

To build the Python package, you first need to install the build package by running the following command:

pip install --upgrade build

Once you have build installed, you can build the package by running:

python3 -m build

If you have any issues or questions, feel free to open an issue on the GitHub repository. We are always happy to help!