Virtual Knowledge Graph (VKG) over the Open Data Hub (ODH) powered by Ontop and curated by Ontopic.

Table of contents

• odh-vkg
  • Getting started
    • Prerequisites
    • Source code
    • Local deployment
      • Docker environment
      • Installation
      • Start and stop the containers
        • Option 1: On the foreground
        • Option 2: On the background
      • Authentication
  • Deployment at NOI - Database synchronization
  • Endpoints
  • Maintenance
    • Schema evolution
    • Test database images
  • Information
    • Support
    • Contributing
    • Documentation
    • License
    • Examples of SPARQL queries
    • Schema

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes.

For a ready to use Docker environment with all prerequisites already installed and prepared, you can check out the Docker environment section.

Get a copy of the repository:

git clone https://github.com/noi-techpark/odh-vkg.git

Change directory:

cd odh-vkg/

1. Create the .env file in which, amongst all, the SPARQL endpoint port and the PG external port (for debugging purposes) are specified
   • cp .env.example .env
2. Start the Docker container (see the dedicated section)
3. Visit the SPARQL endpoint
   • Now we can open the link http://localhost:8080/portal/ in the browser and test some SPARQL queries
   • Note that synchronisation between the master and the slave takes some time. Until it is finished, some queries may return empty results.

For the project a Docker environment is already prepared and ready to use with all necessary prerequisites.

The default Docker Compose file (docker-compose.yml) uses 3 containers:

• A PostgreSQL DB containing a fragment of the ODH Tourism dataset
• Ontop as SPARQL endpoint
• Nginx as reverse proxy and cache

Install Docker (with Docker Compose) locally on your machine.

To start the container on the foreground:

docker-compose pull && docker-compose up --build

The container is run on the foreground and can be stopped by pressing CTRL-C.

To start the container on the background:

docker-compose pull && docker-compose up --build -d

To stop it:

docker-compose down

A second Docker-compose file (docker-compose.auth.yml) can be used for testing access control policies. It requires a running and configurable instance of Keycloak. See https://github.com/noi-techpark/authentication-server for instructions on how to install it locally. Refer to docs/authentication.md for instruction on how to configure Keycloak and the authentication proxy.

All NOI specific infrastructure documentation and scripts can be found inside the infrastructure folder. See infrastructure/README.md for details.

The SPARQL endpoints do not query directly the production database but slave read-only instances, which are synchronized with the master database through two sync-script with scheduled regular executions. The mobility sync can be found under infrastructure/utils/mobility-sync/, whereas the tourism sync is an external program handled directly from the Tourism servers.

• Landing page: /
• Public SPARQL endpoint: /sparql
• Public portal: /portal/
• Public predefined queries: /predefined/
• Portal with restricted access: /restricted/
• SPARQL endpoint with restricted access: /restricted/sparql
• Predefined queries with restricted access: /restricted/predefined/

See the dedicated page

For building a newer version of the Docker image of the test database out of a fresh dump, please refer to Tourism master. This Docker image is published on Docker Hub.

For support, please contact [email protected].

If you'd like to contribute, please follow the following instructions:

• Fork the repository.
• Checkout a topic branch from the main branch.
• Make sure the tests are passing.
• Create a pull request against the main branch.

More documentation can be found at https://docs.opendatahub.com.

The code in this project is licensed under the GNU AFFERO GENERAL PUBLIC LICENSE Version 3 license. See the LICENSE.md file for more information.

Some examples of possible SPARQL queries can be found in the SPARQL Queries folder. You can take a look at some data quality queries here and at some regular queries here.

The schema of the VKG can be visualized in the dedicated page.