Why Bazelle?

The Problem

Setting up Gazelle with multiple languages is complex:

❌ Without Bazelle:
├── Configure rules_go
├── Configure gazelle
├── Find and add gazelle_cc
├── Find and add kotlin gazelle extension (which one?)
├── Find and add python gazelle extension (rules_python_gazelle_plugin?)
├── Wire up all extensions in WORKSPACE/MODULE.bazel
├── Create gazelle targets manually
├── Figure out directives for each language
└── Hope they all work together...

The Solution

Bazelle bundles everything into a single binary:

✅ With Bazelle:
├── bazelle init
├── bazelle update
└── Done.

Before & After

Before (Manual Setup)

MODULE.bazel

# 50+ lines of boilerplate...
bazel_dep(name = "rules_go", version = "0.59.0")
bazel_dep(name = "gazelle", version = "0.47.0")
bazel_dep(name = "rules_kotlin", version = "2.2.2")
bazel_dep(name = "rules_python", version = "1.8.0")
bazel_dep(name = "rules_python_gazelle_plugin", version = "1.6.3")
# ... more deps, more configuration

# Then wire up extensions...
go_deps = use_extension("@gazelle//:extensions.bzl", "go_deps")
go_deps.from_file(go_mod = "//:go.mod")
# ... more extension wiring

BUILD.bazel

load("@gazelle//:def.bzl", "gazelle")
load("@rules_python_gazelle_plugin//:def.bzl", "python_gazelle")
# ... more loads

gazelle(
    name = "gazelle",
    # ... lots of configuration
)

After (Bazelle)

Terminal

# That's it. Really.
bazelle init
bazelle update

BUILD.bazel (generated)

# gazelle:kotlin_enabled true
# gazelle:python_enabled true

# Bazelle handles the rest

Feature Comparison

Feature	Raw Gazelle	Bazelle
Go support	✅ Built-in	✅ Built-in
Proto support	✅ Built-in	✅ Built-in
Kotlin support	⚠️ Find & configure plugin	✅ Built-in, enable with directive
Python support	⚠️ Multiple options, complex setup	✅ Built-in, enable with directive
C/C++ support	⚠️ Find gazelle_cc, configure	✅ Built-in, enable with directive
Incremental updates	❌ Full scan every time	✅ Only changed directories
Watch mode	❌ Not available	✅ Built-in file watcher
Project init	❌ Manual setup	✅ bazelle init
CI check mode	⚠️ Manual diff setup	✅ --check flag
Single binary	❌ Multiple dependencies	✅ One binary, all extensions

How It Works

┌─────────────────────────────────────────────────────────────┐
│                        Bazelle CLI                          │
│  ┌─────────┐ ┌─────────┐ ┌─────────┐ ┌─────────┐           │
│  │  init   │ │ update  │ │   fix   │ │  watch  │           │
│  └────┬────┘ └────┬────┘ └────┬────┘ └────┬────┘           │
│       │           │           │           │                 │
│       └───────────┴───────────┴───────────┘                 │
│                         │                                   │
│              ┌──────────▼──────────┐                        │
│              │   Gazelle Runner    │                        │
│              └──────────┬──────────┘                        │
│                         │                                   │
│    ┌────────────────────┼────────────────────┐              │
│    │                    │                    │              │
│    ▼                    ▼                    ▼              │
│ ┌──────┐ ┌──────┐ ┌──────────┐ ┌──────────┐ ┌────────┐     │
│ │  Go  │ │Proto │ │  Kotlin  │ │  Python  │ │  C/C++ │     │
│ │(core)│ │(core)│ │(gazelle- │ │(gazelle- │ │(gazelle│     │
│ │      │ │      │ │ kotlin)  │ │ python)  │ │  _cc)  │     │
│ └──────┘ └──────┘ └──────────┘ └──────────┘ └────────┘     │
│                                                             │
│              All extensions pre-configured                  │
└─────────────────────────────────────────────────────────────┘

Real-World Example

A typical monorepo with Go, Kotlin, and Python:

my-company/
├── MODULE.bazel
├── BUILD.bazel          # gazelle:kotlin_enabled true
│                        # gazelle:python_enabled true
├── services/
│   ├── api/             # Go service
│   │   ├── main.go
│   │   └── BUILD.bazel  # ← generated: go_binary
│   └── auth/            # Kotlin service
│       └── src/main/kotlin/
│           └── Auth.kt
│           └── BUILD.bazel  # ← generated: kt_jvm_library
├── libs/
│   └── ml/              # Python library
│       ├── model.py
│       └── BUILD.bazel  # ← generated: py_library
└── proto/
    └── api.proto
    └── BUILD.bazel      # ← generated: proto_library

One command updates all BUILD files:

bazelle update

Time Savings

Task	Manual Setup	With Bazelle
Initial project setup	Hours	Minutes
Adding a new language	30+ minutes	1 directive
Updating BUILD files	Run gazelle, check config	bazelle update
CI integration	Custom scripts	bazelle update --check
New developer onboarding	Read docs, understand setup	bazelle init && bazelle update

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