Development

Vision and principles

Consistency and coherence are one of the key characteristics of good software. While the reality is never black and white, it is important that contributors are working towards the same high-level goal. This document attempts to set out the basic principles and the rationale behind them. If you are contributing or looking to evaluate whether lean-ftl is the right choice for your project, it might be worthwhile to skim through the section below.

Mission statement

lean-ftl is the compact and safe library easily portable.

Goals

Robustness

lean-ftl shall cope with sudden power loss at any point except for a few, well identified functions.

Rational Embedded systems are typically deployed in a harsh environment: planet Earth, full of careless and/or mal attentioned humans.

Simplicity

lean-ftl shall be as simple as possible to keep the code base minimal.

Rational

• Minimal code base ease code reviews.

• Complexity is the main source of bugs and security vulnerabilities.

Self-contained

lean-ftl has no dependencies, it can run on bare-metal.

Portability

lean-ftl aim at being usable on any MCU.

That said, lean-ftl has been tested so far only on little-endian devices. It has been tested on STM32 MCUs only but it is designed to be portable to other MCUs and even handle external NVMs such as QSPI flash, SDcards…

Stable API

lean-ftl will not break backward compatibility unexpectly.

Rational lean-ftl use Industry-standard versioning is a basic requirement for production-quality software. This is especially relevant in IoT environments where updates may be costly.

Development dependencies

• CMake 3.30 or newer

• gcc 11.4.0 or newer

• arm-none-eabi-gcc 14.2.1 or newer

All other dependencies are related to documentation:

• Python and pipenv

• Doxygen

• Sphinx

Installing sphinx

pipenv install

Further instructions on configuring advanced features can be found at http://read-the-docs.readthedocs.org/en/latest/install.html.

Tips and tricks

Live preview of docs

pipenv run make -C doc livehtml

This updates the html and refresh it in the browser each time something within doc folder changes. If you change something in the sources, use pipenv run make -C doc to see the effect.

Testing and code coverage

Please refer to Tests

Debug preprocessor macros

make -C build/linux/ test/source/main.i

This generate the file build/linux/CMakeFiles/lean-ftl-test.dir/test/source/main.c.i

Type the following to see the full list of available targets:

make -C build/linux/ help