GitFarm: Git® as a Service for Large-Scale Monorepos

Summary

At Uber’s monorepo scale, traditional Git workflows create bottlenecks through multi-gigabyte clones, local checkouts, repeated synchronization, and independent fetch or push operations across automation systems. The post describes GitFarm, a Git as a Service platform exposed through a high-performance gRPC API that executes standard Git commands in secure, ephemeral sandboxes backed by pre-warmed repository and container pools. Each backend maintains a bare clone, receives push-based updates and periodic git fetch operations every five minutes, while clients can explicitly fetch when they need current state. The design provides a full checkout in under 500 milliseconds and reduced client-side resource utilization by over 80%, while avoiding local clones and long initial clone delays.

Takeaways

1. 1

   GitFarm is not a Git SCM: it executes standard Git commands on behalf of services but does not store, replicate, or serve repositories.

2. 2

   Repository freshness is configurable per request: clients can run an explicit git fetch for current state, or rely on eventually consistent backend synchronization to reduce latency and redundant fetches.

3. 3

   Production use reduced client-side resource utilization by over 80%, and clients can obtain a full Git checkout in under 500 milliseconds.