Welcome to HoloHub!

Holohub is a central repository for users and developers of extensions and applications for the Holoscan Platform to share reusable components and sample applications.

Table of Contents

• Prerequisites
• Building HoloHub
• Running applications
• Contributing to HoloHub
• Useful Links

Prerequisites

HoloHub is based on Holoscan SDK. HoloHub has been tested and is known to run on Ubuntu 20.04. Other versions of Ubuntu or OS distributions may result in build and/or runtime issues.

1. Refer to the Holoscan SDK README for ways to install Holoscan SDK: Debian package, Python wheels, container or from source.

2. Clone this repository.

3. Install the package dependencies. The easiest way to make sure the minimal package dependencies is to use the run script from the top level directory.

  # if sudo is available
  sudo ./run setup
  # if sudo is not available (container)
  ./run setup

If you prefer you can also install the dependencies manually:

• CMake: 3.20.1+
• Python interpreter: 3.8 to 3.11
• Python dev: 3.8 to 3.11 (matching version of the interpreter)
• ffmpeg runtime
• ngc-cli
• wget
• CUDA: 11.6 or 11.8 (CUDA 12 is not supported yet)
• libcudnn8
• libcudnn8-dev
• libnvinfer-dev
• libnvinfer-plugin-dev
• libnvonnxparsers-dev

Note: the run script setup installs the minimal set of dependencies required to run the sample applications. Other applications might require more dependencies. Please refer to the README of each application for more information.

Building HoloHub

While not all applications requires building HoloHub, the current build system automatically manages dependencies (applications/operators) and also downloads and convert datasets at build time. HoloHub provides a convenient run script to build and run applications (you can run ./run -h for information about the available commands).

You can refer to the README of each application/operator if you prefer to build/run them manually.

Make sure you have installed the prerequisites before attempting to build HoloHub.

Building Sample applications

Sample applications based on the Holoscan Platform may be found under the Applications directory. Sample applications are a subset of the HoloHub applications and are maintained by Holoscan SDK developers to provide a demonstration of the SDK capabilities.

To build sample applications, make sure you have install the prerequisites and setup your NGC credentials then run:

  ./run build

Alternatively if you have an installation of the Holoscan SDK which is not in a standard path, you may want to provide the root directory of your Holoscan SDK installation.

  ./run build --sdk <path to the Holoscan SDK installation directory>

Note that the run script creates a data directory to put the downloaded Holohub data where the run script is located. This directory is noted HOLOHUB_DATA_DIR/holohub_data_dir in the documentation, READMEs and metadata files.

When the build is successful you can run the sample applications

Building a specific application

By default HoloHub builds the sample applications that are maintained with the SDK, but you can build specific applications by the name of the directory.

  ./run build <application>

for example:

  ./run build endoscopy_tool_tracking

Note that CMake with build the application in the directory specified if there are multiple languages, the script will attempt to build all of them.

Building application or operator manually

If you prefer to build applications and operator manually you can follow the steps below.

# Export cuda (in case it's not already in the path)
export PATH=$PATH:/usr/local/cuda/bin

# Configure Holohub with CMake
cmake -S <path_to_holohub_source>            # Source directory
      -B build                               # Build directory
      -DPython3_EXECUTABLE=/usr/bin/python3  # Specifies the python executable for CMake to find the correct version
      -DHOLOHUB_DATA_DIR=$(pwd)/data         # Specifies the data directory
      -DBUILD_SAMPLE_APPS=1                  # If you want to build the sample applications
      or
      -DAPP_<name_of_the_application>=1      # To build a specific application


# Build the application(s)
cmake --build build

Running applications

To list all available applications you can run the following command:

  ./run list

Then you can run the application using

  ./run launch <application> <language>

For example to run the tool tracking endoscopy application in C++

  ./run launch endoscopy_tool_tracking cpp

and to run the same application in python:

  ./run launch endoscopy_tool_tracking python

The run script reads the "run" command from the metadata.json file for a given application and runs from the "workdir" directory. Make sure you build the application (if applicable) before running it.

Contributing to HoloHub

The goal of Holohub is to allow engineering teams to easily contribute and share new functionalities and demonstration applications. Please review the CONTRIBUTING.md file for more information on how to contribute.

Useful Links

• Holoscan GitHub organization
• Holoscan SDK repository