Using ViRelAy With Gunicorn

As described in the Basic Usage and Features articles, ViRelAy provides a command-line interface to serve the web application using a simple built-in HTTP server. While this built-in server is suitable for small projects and testing purposes, it may not provide the performance and scalability required for larger-scale deployments, such as required when installing ViRelAy on a remote server for collaborative work.

To unlock faster performance and scalability, we recommend running ViRelAy with Gunicorn , a WSGI-compliant HTTP server that provides robust features and configuration options. Gunicorn is installed alongside ViRelAy by default, but you can also install a specific version using pip install gunicorn.

To start ViRelAy using Gunicorn, use the following command:

$ gunicorn \
    --workers 4 \
    --bind 127.0.0.1:8000 \
    "virelay.application:run_wsgi_app(projects=['path/to/project-1.yaml', 'path/to/project-2.yaml'])"

This command starts the Gunicorn server with the following settings:

--workers 4 – Runs four worker processes to handle incoming requests.
--bind 127.0.0.1:8000 – Binds the server to 127.0.0.1 on port 8000.
virelay.application:run_wsgi_app(projects=[...])" – Starts ViRelAy in a WSGI-compatible mode. The projects argument instructs ViRelAy to loads two projects, project-1.yaml and project-2.yaml.

You can specify multiple projects by passing a list of project paths as shown above. Alternatively, you can set the VIRELAY_PROJECTS environment variable to a colon-separated list of project paths:

$ export VIRELAY_PROJECTS="path/to/project-1.yaml:path/to/project-2.yaml"
$ gunicorn \
    --workers 4 \
    --bind 127.0.0.1:8000 \
    "virelay.application:run_wsgi_app()"

Note that passing the projects explicitly to run_wsgi_app() takes precedence over the environment variable, i.e., if you use run_wsgi_app(projects=[...]), VIRELAY_PROJECTS is ignored.