NOS-T Tools API

This page contains descriptions of the NOS-T tools library features, and provides a detailed description of their functions. Within this library, there are templates to support both time-managed and time-agnostic applications. The first step for using the tools library is to follow the installation instructions.

The tools consist of ten Python files defining useful methods and classes. For logical convenience they are categorized into the following three sections:

  • Message Schemas:

    Define the information carried in common message payloads and the format that information should take using the Pydantic data validation library.

    • Command messages: Used by the manager to control time-managed scenarios. These are further described in this section of the Interface Control Document (ICD).

    • Status messages: Used by all constituent applications to update simulation time and modes. These are further described in this section of the ICD.

  • Simulator Objects:

    Manage state changes and internal clocks for simulation applications.

    • Observer Objects: Implement patterns for loosely coupling observables and observers.

    • Scenario Objects: Define states and methods for executing a simulation.

  • Applications Objects:

    Help constituent applications connect to the MQTT message broker and communicate with the MQTT messaging protocol.

    • Utilities: Monitor and report on application connections, modes, and time statuses.

    • Publishers: Define patterns for publishing messages on regularly spaced time-intervals.

    • Applications: Serve as templates or wrappers of basic MQTT client functionality and synchronization for simulation.

The NOS-T Example Test Suites feature many different implementations of the tools. In particular, all of the Python FireSat+ applications make use of the NOS-T tools library for a faster than real-time simulation that requires coordination from a Manager application. Furthermore, the example application templates include a collection of bare-bones templates, similar to FireSat+, with some of the tools functionality built-in.