Processes

InvenTree Processes¶

InvenTree is a complex application, and there are a number of processes which must be running in order for the system to operate correctly. Typically, these processes are started automatically when the InvenTree application stack is launched. However, in some cases, it may be necessary to start these processes manually.

System administrators should be aware of the following processes when configuring an InvenTree installation:

Database¶

At the core of the InvenTree application is the SQL database. The database is responsible for storing all of the persistent data which is used by the InvenTree application.

InvenTree supports a number of database backends - which typically require their own process to be running.

Refer to the database configuration guide for more information on selecting and configuring the database backend.

In running InvenTree via docker compose, the database process is managed by the inventree-db service which provides a Postgres docker container.

Web Server¶

The InvenTree web server is responsible for serving the InvenTree web interface to users. The web server is a Django application, which is run using the Gunicorn WSGI server.

The web server interfaces with the backend database and provides a REST API (via the Django REST framework) which is used by the frontend web interface.

In running InvenTree via docker compose, the web server process is managed by the inventree-server service, which runs from a custom docker image.

Proxy Server¶

In a production installation, the InvenTree web server application does not provide hosting of static files, or user-uploaded (media) files. Instead, these files should be served by a separate web server, such as Caddy, Nginx, or Apache.

Debug Mode

When running in production mode (i.e. the INVENTREE_DEBUG flag is disabled), a separate web server is required for serving static and media files. In DEBUG mode, the django webserver facilitates delivery of static and media files, but this is explicitly not suitable for a production environment.

Static Files¶

Static files can be served without any need for authentication. In fact, they must be accessible without authentication, otherwise the unauthenticated views (such as the login screen) will not function correctly.

Media Files¶

It is highly recommended that the media files are served behind an authentication layer. This is because the media files are user-uploaded, and may contain sensitive information. Most modern web servers provide a way to serve files behind an authentication layer.

Example Configuration¶

The docker production example provides an example using Caddy to serve static and media files, and redirecting other requests to the InvenTree web server itself.

Caddy is a modern web server which is easy to configure and provides a number of useful features, including automatic SSL certificate generation.

Alternatives to Caddy¶

An alternative is to run nginx as the reverse proxy. A sample configuration file is provided in the ./contrib/container/ source directory.

Integrating with Existing Proxy¶

You may wish to integrate the InvenTree web server with an existing reverse proxy server. This is possible, but requires careful configuration to ensure that the static and media files are served correctly.

Note: A custom configuration of the proxy server is outside the scope of this documentation!

Background Worker¶

The InvenTree background worker is responsible for handling asynchronous tasks which are not suitable for the main web server process. This includes tasks such as sending emails, generating reports, and other long-running tasks.

InvenTree uses the django-q2 package to manage background tasks.

The background worker process is managed by the inventree-worker service in the docker compose setup. Note that this services runs a duplicate copy of the inventree-server container, but with a different entrypoint command which starts the background worker process.

Important Information¶

If the background worker process is not running, InvenTree will not be able to perform background tasks. This can lead to issues such as emails not being sent, or reports not being generated. Additionally, certain data may not be updated correctly if the background worker is not running.

Background Worker

The background worker process is a critical part of the InvenTree application stack. It is important that this process is running correctly in order for the InvenTree application to operate correctly.

Limitations¶

If the cache server is not running, the background worker will be limited to running a single threaded worker. This is because the background worker uses the cache server to manage task locking, and without a global cache server to communicate between processes, concurrency issues can occur.

Cache Server¶

The InvenTree cache server is used to store temporary data which is shared between the InvenTree web server and the background worker processes. The cache server is also used to store task information, and to manage task locking between the background worker processes.

Using a cache server can significantly improve the performance of the InvenTree application, as it reduces the need to query the database for frequently accessed data.

InvenTree uses the Redis cache server to manage cache data. When running in docker, we use the official redis image.

Redis on Docker

Docker adds an additional network layer - that might lead to lower performance than bare metal. To optimize and configure your redis deployment follow the official docker guide.

Enable Cache

While a redis container is provided in the default configuration, by default it is not enabled in the InvenTree server. You can enable redis cache support by following the caching configuration guide