🏢
Monorepo V3
Google-Scale Source Control
🗺️Foundations▾
Ch 0 — Foundations
🎯⚡
Ch 1 — The Cost Model of a Monorepo
🎯
Ch 2 — Dependency Graphs and Ownership
🎯
📐Source Control at Scale▾
Ch 3 — Large-Scale Monorepos
🎯⚡
Ch 4 — Google's Monorepo Philosophy
🎯
Ch 5 — Trunk, Releases, and Change Management
🎯
🗄️Piper▾
Ch 6 — Piper
🎯⚡
Ch 7 — Piper Data Model
🎯
Ch 8 — Consistency, History, and Safe Writes
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☁️CITC Workspaces▾
Ch 9 — CITC (Client in the Cloud)
🎯⚡
Ch 10 — CITC Read and Write Paths
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Ch 11 — Remote Development and Failure Modes
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🔨Build Systems (Bazel + Starlark)▸
🔍Review & Analysis▸
⚙️Execution (Borg)▸
🛡️Deployment & Security▸
🔄External Code Flow▸
🚀End-to-End Architecture▸
Chapters read0/28
🧩 Platform engineering path

Google-Scale Monorepo

A visual route from source control and workspaces to build graphs, review, execution, and safe delivery.

10 parts28 chapters48 terms
🧩
PiperCITCBazelBorgBAB
Source → build → production
Version 3.0 · 2026

From Git to Piper-Scale Source Control

28 Chapters · From Foundations to Google-Scale Architecture

28
Chapters
10
Parts
28
Quizzes
48
Terms
📍 Choose a Learning Path
Novice Path
Architecture, ownership, source control, and workspaces
Engineer Track
Build graphs, presubmit, scheduling, and reliability
Researcher Route
Piper internals, virtual filesystems, and execution
Executive View
Ownership, delivery, security, and platform metrics
🗺️Part 0 — Foundations
⚡🎯
Ch 0
Foundations
Why one repository, why not, and what changes when you commit to it.
🎯
Ch 1
The Cost Model of a Monorepo
Make the tradeoffs explicit before choosing the repository shape.
🎯
Ch 2
Dependency Graphs and Ownership
Turn a directory tree into a system people can reason about.
📐Part 1 — Source Control at Scale
⚡🎯
Ch 3
Large-Scale Monorepos
When 'git clone' takes an hour and 'grep' never finishes.
🎯
Ch 4
Google's Monorepo Philosophy
Atomic changes, global visibility, and the organizational consequences of one repository.
🎯
Ch 5
Trunk, Releases, and Change Management
Learn how a fast mainline stays stable without a branch for every feature.
🗄️Part 2 — Piper
⚡🎯
Ch 6
Piper
Why Git doesn't work at 2 billion lines, and what replaces it.
🎯
Ch 7
Piper Data Model
Separate names, revisions, metadata, and content so scale does not collapse the system.
🎯
Ch 8
Consistency, History, and Safe Writes
Make concurrent edits predictable when thousands of engineers land changes.
☁️Part 3 — CITC Workspaces
⚡🎯
Ch 9
CITC (Client in the Cloud)
Your working copy lives in the cloud; your laptop only sees what you touch.
🎯
Ch 10
CITC Read and Write Paths
Understand what happens when a virtual workspace opens, reads, and edits a file.
🎯
Ch 11
Remote Development and Failure Modes
Design a cloud workspace that remains useful when networks and machines fail.
🔨Part 4 — Build Systems (Bazel + Starlark)
⚡🎯
Ch 12
Bazel (Blaze)
The build graph becomes the monorepo's nervous system.
⚡🎯
Ch 13
Starlark (Bazel's Configuration Language)
The language that makes Bazel extensible without being Turing-complete.
🎯
Ch 14
Build Graph Design
Move from compiling files to analyzing actions and dependencies.
🔍Part 5 — Review & Analysis
⚡🎯
Ch 15
Critique (Code Review)
The single gate that keeps the monorepo green.
⚡🎯
Ch 16
Tricorder (Static Analysis)
Program analysis as a scalable ecosystem.
🎯
Ch 17
Presubmit as a Distributed System
Make review fast enough that safety does not become a queue.
⚙️Part 6 — Execution (Borg)
⚡🎯
Ch 18
Borg (Cluster Management)
The system that runs everything at Google.
🎯
Ch 19
Borg Scheduling Fundamentals
Place work on machines while balancing utilization, latency, and failure risk.
🎯
Ch 20
Service Reliability and Capacity
Turn placement into a reliable production service.
🛡️Part 7 — Deployment & Security
⚡🎯
Ch 21
BAB (Binary Authorization for Borg)
Ensuring only reviewed, authorized code reaches production.
🎯
Ch 22
Release Engineering and Progressive Delivery
Move a reviewed build to users without turning deployment into a cliff.
🎯
Ch 23
Identity, Secrets, and Supply Chain
Connect source provenance to the permissions a running service receives.
🔄Part 8 — External Code Flow
⚡🎯
Ch 24
Copybara (External Code Flow)
Moving code between internal and external repositories.
🎯
Ch 25
Mirrors, Open Source, and Repository Boundaries
Share code externally without confusing synchronization with authority.
🚀Part 9 — End-to-End Architecture
⚡🎯
Ch 26
End-to-End Google Engineering
How all the pieces fit together.
🎯
Ch 27
Operating the Developer Platform
Measure whether the system is making engineers faster and safer.