.. Appendix

Embedded Software Dependencies
==============================

Like most software, L7|ESP relies on a number of open-source component to
function. At L7 Informatics, we track the version, license and security issues
of each of these. For visibility into the underlying technology stack, each
dependency is listed below.

.. contents:: Table of Contents
    :depth: 2
    :local:

Backend
-------

L7|ESP runs as several independent processes that communicate with each other
via TCP/IP-based protocols. The process tree spawned by L7|ESP is detailed in
figure 1:

.. figure:: ../_static/supervisor-services.png
   :alt: L7|ESP Process Tree
   :align: center
   :width: 50%

   Figure 1. L7|ESP Process Tree

The L7|ESP backend is written primarily in Python, as such we rely on the
following packages which are made available through PyPI:

.. autosnyk::
   :org: l7informatics
   :project_name: Backend

The PDF service uses the popular Node library Puppeteer to control Chrome:

.. autosnyk::
   :org: l7informatics
   :project_name: PDFService

Frontend
--------

The L7|ESP web interface is written in VueJS and runs in your browser. The
following JavaScript libraries are embedded in each build of the frontend:

.. autosnyk::
   :org: l7informatics
   :project_name: Frontend

System Libraries
----------------

L7|ESP ships as a container image built on top of the stable and dependable Debian
Linux distribution. The latest major release is currently Debian 11 (Bullseye).

This container image includes major components for running the platform,
such as database software (PostgreSQL, Redis) and programming language
interpreters (Python, NodeJS).

.. autosnyk::
   :org: l7informatics
   :project_name: SystemLibraries
   :debian: true
   :integration_id: 144df21b-16ae-4de2-9b36-e8de604580f3
   :project_id: f7ab3a0e-eeb4-4349-a245-a2893241c6fa