Hello Bazel

A collection of simple Bazel examples demonstrating how to build projects in different programming languages using modern Bzlmod.

Contents

1. Go Example (//hello-go:hello-go)

   • Web server using Fuego framework
   • Internal package structure
   • Unit tests with go_test

2. Python Example (//hello-py:hello)

   • Python binary example
   • Demonstrates py_binary rule

Prerequisites

• Bazel 7.x or later (uses Bzlmod)
• Go toolchain (auto-downloaded by Bazel)
• Python 3.x (for Python examples)

Building

# Build all targets
bazel build //...

# Build specific targets
bazel build //hello-go:hello-go
bazel build //hello-py:hello

Running

# Run Go server (starts on :9999)
bazel run //hello-go:hello-go

# Run Python example
bazel run //hello-py:hello

Testing

# Run all tests
bazel test //...

# Run Go tests only
bazel test //hello-go/...

# Run with verbose output
bazel test //... --test_output=all

Development

Regenerate BUILD Files

# Update BUILD files from Go source
bazel run //:gazelle

# Update dependencies from go.mod
bazel run //:gazelle-update-repos

IDE Setup (VS Code / GoLand)

For Go IDE integration with Bazel, set the GOPACKAGESDRIVER environment variable:

export GOPACKAGESDRIVER="$(pwd)/tools/gopackagesdriver.sh"

See rules_go Editor Setup for details.

Static Analysis

This project uses nogo for static analysis during builds:

• Go vet checks (enabled by default)
• Nilness analysis (detect nil pointer dereferences)
• Shadow analysis (detect shadowed variables)
• Unused result analysis (detect ignored return values)

Analysis runs automatically on every build - no separate step needed.

CI/CD

GitHub Actions workflow runs on push and PR:

• Builds all targets with optimizations
• Runs all tests
• Uses Bazel caching for fast builds

Project Structure

hello-bazel/
├── BUILD.bazel              # Root gazelle targets
├── MODULE.bazel             # Bazel module configuration
├── .bazelrc                 # Bazel settings
├── hello-go/
│   ├── BUILD.bazel          # Go binary and nogo rules
│   ├── main.go              # Server entry point
│   ├── go.mod               # Go module
│   └── internal/handler/    # Internal packages
│       ├── BUILD.bazel
│       ├── hello.go
│       └── hello_test.go
├── hello-py/
│   ├── BUILD.bazel
│   └── main.py
└── tools/
    └── gopackagesdriver.sh  # IDE integration