Tech Stacks - Source Control

Source Control: git / hg / jj

Modern code repos usually live in either git or Mercurial (hg). jj is a new player written in Rust.

• git
  • https://www.git-scm.com/
  • written in C
  • Google stores most of its code in its own system ("Piper"), but some Android, Chrome, Cloud related repos live in git.
• hg
  • https://www.mercurial-scm.org/
  • written in Python
  • better support for larger repos.
  • used by Facebook
• jj
  • https://github.com/jj-vcs/jj
  • written in Rust

Gitlab

Persistent storage for the stateful components:

• PostgreSQL (GitLab data)
• Redis (session data)
• Gitaly (git repo data): Git RPC service for handling all Git calls made by GitLab. Requests => Gitaly => .git repos.
  • Before Gitaly: all requests direct calls to .git directory stored on NFS mounts connected to the GitLab server. Gitaly removed direct access to the .git directory.
• GitLab Shell: handles git SSH sessions for GitLab and modifies the list of authorized keys. GitLab Shell is not a Unix shell. GitLab Shell is used for tasks such as for git clone, git push etc executed via SSH.

https://docs.gitlab.com/ee/development/architecture.html

In k8s, a gitlab deployed in the admin cluster can be used for IaC.

Code repo structure

• single repo or not?
• single branch or not?

Code Search

You probably need a good way to search and browse your code. E.g. git itself manages the code, while GitHub provides a good UI to view the code.

Code Review

Gerrit (https://www.gerritcodereview.com/) is a widely used code review tool. Originated from Google, and now also being used for Google's git repos.