Bazel Build Optimization

Production patterns for Bazel in large-scale monorepos.

When to Use This Skill

Setting up Bazel for monorepos
Configuring remote caching/execution
Optimizing build times
Writing custom Bazel rules
Debugging build issues
Migrating to Bazel

Core Concepts

1. Bazel Architecture

text

workspace/
├── WORKSPACE.bazel       # External dependencies
├── .bazelrc              # Build configurations
├── .bazelversion         # Bazel version
├── BUILD.bazel           # Root build file
├── apps/
│   └── web/
│       └── BUILD.bazel
├── libs/
│   └── utils/
│       └── BUILD.bazel
└── tools/
    └── bazel/
        └── rules/

2. Key Concepts

Concept	Description
Target	Buildable unit (library, binary, test)
Package	Directory with BUILD file
Label	Target identifier `//path/to:target`
Rule	Defines how to build a target
Aspect	Cross-cutting build behavior

Templates and detailed worked examples

Full template library and detailed worked examples live in references/details.md. Read that file when you need the concrete templates.

Best Practices

Do's

Use fine-grained targets - Better caching
Pin dependencies - Reproducible builds
Enable remote caching - Share build artifacts
Use visibility wisely - Enforce architecture
Write BUILD files per directory - Standard convention

Don'ts

Don't use glob for deps - Explicit is better
Don't commit bazel-* dirs - Add to .gitignore
Don't skip WORKSPACE setup - Foundation of build
Don't ignore build warnings - Technical debt