Trunk-based development

02/19/25 • 50 min

In this episode, Jeff and Luca discuss trunk-based development, a software development practice where developers merge their work into the main branch (trunk) frequently - at least daily. They explain how this approach differs from traditional branching models like GitFlow, and address common objections and concerns. The hosts emphasize that while trunk-based development may seem risky, it actually reduces risk by exposing integration problems early and forcing teams to implement good engineering practices like automated testing and feature flags.

The discussion highlights how trunk-based development acts as a "forcing function" that encourages better development practices, smaller changes, and more frequent collaboration between team members. They explain that while this approach originated in web development, it's equally applicable to embedded systems. The hosts cite research from the book "Accelerate" showing that trunk-based development is a predictor of high-performing software teams.

The episode concludes by emphasizing that most objections to trunk-based development actually point to underlying process issues that need to be addressed, and that the benefits of early integration and feedback outweigh the perceived downsides.

Timestamps:
00:00:00 - Introduction and topic overview
00:03:00 - Basic version control concepts and branching
00:08:00 - Definition and principles of trunk-based development
00:13:00 - Feature flags explanation and implementation
00:20:00 - Common objections to trunk-based development
00:27:00 - Application to embedded systems
00:34:00 - Benefits of trunk-based development
00:40:00 - Impact on team dynamics and collaboration
00:47:00 - Research backing and evidence from "Accelerate"

Shownotes / Links:
MinimumCD: https://minimumcd.org/
Accelerate: https://www.goodreads.com/book/show/35747076-accelerate
The nvie branching model: https://nvie.com/posts/a-successful-git-branching-model/

You can find Jeff at https://jeffgable.com.
You can find Luca at https://luca.engineer.

Want to join the agile Embedded Slack? Click here

You can find Jeff at https://jeffgable.com.
You can find Luca at https://luca.engineer.

Want to join the agile Embedded Slack? Click here

Previous Episode

QP framework with Mitch English

The episode features a discussion with Mitch English, a product development team lead at Inertia, about using the QP (Quantum Platform) framework for embedded systems development. Mitch and Jeff recently collaborated on a medical device project where they successfully implemented QP. The framework, created by Miro Samek, implements the actor model with active objects running in their own threads and communicating via messages. This approach helps avoid common concurrency issues found in traditional RTOS implementations.

The discussion covers how QP's hierarchical state machine framework makes it easier to manage complex state transitions and system behaviors. They share their experience using QP on a blood analyzer project, discussing how they structured the code with different layers of abstraction and maintained multiple test builds throughout development. The team found that QP's architecture helped make the system's complexity more manageable and testable.

A key learning they shared was about event communication - while they initially used direct posting between active objects, they later realized that using the publish-subscribe pattern more extensively would have made testing easier and the system more flexible. They recommend starting with QP's simple examples and gradually building up complexity rather than trying to implement complex examples right away.

Key Timestamps:
00:00:00 - Introduction and background
00:03:00 - Overview of QP framework and actor model
00:06:30 - Discussion of hierarchical state machines
00:19:30 - Project architecture and implementation approach
00:27:00 - Testing strategies and development process
00:30:00 - Team structure and collaboration
00:35:00 - Hardware/software integration
00:39:00 - Advice for getting started with QP
00:41:50 - About Inertia and contact information

Links:

Miro Samek's QP framework: https://www.state-machine.com/products/qp
Miro's book on QP framework: https://www.state-machine.com/psicc2
QP GitHub repository with example code: https://github.com/QuantumLeaps/qpc-examples
Inertia website: http://www.inertiapd.com/
Mitch English LinkedIn: https://www.linkedin.com/in/mitchellenglish/

You can find Jeff at https://jeffgable.com.
You can find Luca at https://luca.engineer.

Want to join the agile Embedded Slack? Click here

Next Episode

John Taylor on the Embedded Systems Cookbook

John Taylor returns to the podcast to discuss his new book "The Embedded Project Cookbook", co-authored with Wayne Taylor. The book serves as a practical guide for embedded systems development, providing recipes and techniques that John has refined over his 30+ year career. Unlike his previous book "Patterns in the Machine" which focused on software engineering best practices, this new book takes a more hands-on approach to project mechanics - from requirements gathering through release.

The book provides opinionated guidance on setting up project infrastructure, managing requirements, software architecture, and release processes. While organized in a waterfall-like structure for clarity, it emphasizes the need for agility in embedded development. A key theme is establishing good practices early to make releases boring and predictable rather than chaotic.

The content is valuable for different roles - from junior developers seeking context about the full development lifecycle, to technical leads implementing processes, to managers needing justification for development infrastructure investments. While the book presents John's specific approaches, he emphasizes that teams can adapt the recipes to their needs as long as they deliberately address the underlying challenges.

Key Topics Discussed (Timestamps):
00:00:00 - Introduction and background on John Taylor
00:02:00 - Comparison to previous book "Patterns in the Machine"
00:06:00 - Target audience and use cases
00:15:00 - Software Development Plans and their value
00:20:00 - Foundation setup before coding begins
00:27:00 - Managing project variants and configurations
00:30:00 - Communication and collaboration practices
00:35:00 - Release management and ongoing development
00:40:00 - Iterative development cycles
00:43:00 - Book availability and contact information

Links:
Embedded Systems Cookbook: https://link.springer.com/book/10.1007/979-8-8688-0327-7
Patterns in the machine (the previous book): https://link.springer.com/book/10.1007/978-1-4842-6440-9
John's LinkedIn: https://www.linkedin.com/in/john-tanner-taylor/

You can find Jeff at https://jeffgable.com.
You can find Luca at https://luca.engineer.

Want to join the agile Embedded Slack? Click here