buck2-rule-basics

To write a basic Buck2 rule in Starlark, you define the rule implementation function, declare attributes, and register actions. This interactive tutorial guides you step-by-step through building a simple uppercase transformation rule.

Configured and unconfigured targets in Buck2 differ based on select() evaluation and configuration constraints. The tutorial explains this analysis model, teaching how to transition targets from unconfigured to configured states using configuration-aware patterns.

Running actions and managing artifacts in a Buck2 build system involves declaring actions within your rule implementation to produce output artifacts. The tutorial provides hands-on practice with these core concepts across eight interactive steps.

You can learn Buck2 rule basics without prior build system experience, as the tutorial starts with a minimal rule and progresses to configuration-aware patterns. It includes reference materials and tracks your progress interactively.

The select() function in Buck2 works by mapping configuration constraints to specific attribute values during the analysis phase. This tutorial covers select() extensively, demonstrating how to apply configuration-aware patterns to your rules.

A Buck2 rule might fail during the analysis phase due to incorrect attribute declarations or invalid artifact references. The tutorial's references and example files help diagnose these issues by demonstrating correct analysis and execution models.