Git post

content/rambles/git-server.md

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+---
+title: 'Hosting your own Git "server"'
+date: "2022-09-30T14:27:31+02:00"
+author: "$HUMANOID"
+tags: ["git", "ssh"]
+description: "The basis of a Git server is a machine accessible in a way that git understands with a bunch of bare git repositories"
+toc: true
+---
+
+# Introduction
+
+Pretty much the moment I started to work with Git a few years ago, I've wanted to host my own server.
+I didn't really bother looking into how that could work for a very long time.
+I assumed it would be rather complex considering Git itself is an extremely complex (set of) tool(s) to work with.
+I was hilariously wrong.
+It's _so_ simple to me that I'm under the impression that the lack of posts regarding the topic on blogs like this, is because it's so simple.
+Still, I'm going to spend the rest of this post explaining how to set up a server and why even calling a basic configuration a server, is a bit of an exaggeration.
+
+# Setting up the server
+
+The first step is to set up a Unix box of any kind.
+Linux, any of the BSDs and probably even Darwin will work (hell, even Haiku might suffice).
+The rest of this post assumes a Debian system.
+Basics requirements are quite few:
+
+- It needs to be accessible using SSH.
+- It needs Git installed.
+
+## Adding an account
+
+Common practice dictates that you have a dedicated account for managing your Git repositories.
+Common practice again dictates that this account be called `git`.
+Its home directory doesn't really matter, but I like tossing it into `/srv/git`.
+Login shell also doesn't matter _yet_, I tend to change it to `bash` for when I need to do things as the `git` user.
+
+You can create an account with the following:
+```sh
+sudo useradd git -md /srv/git -s /bin/bash
+```
+- `-d` specifies where the home directory should be
+- `-m` creates the home directory
+- `-s` specifies what binary to use as login shell
+
+## Setting up SSH
+
+### Client side
+
+On the machine from where you want to push your git repositories, generate a new SSH key to access your Git server:
+```sh
+ssh-keygen -t ed25519 -f ~/.ssh/<git-key>
+```
+I also recommend creating an entry in `~/.ssh/config` for your Git server:
+```ssh_config
+Host <host>
+	Hostname <hostname>
+	User git
+	Identityfile ~/.ssh/<git-key>
+```
+
+### Server side
+Next step is to make the `git` account accessible over SSH.
+To do this, log in as the `git` user and create a `.ssh` directory with an `authorized_keys` file with the public half of the `<git-key>` keypair:
+```sh
+sudo su - git
+umask 077 # strict read write permissions
+mkdir ~/.ssh
+cat <git-key>.pub >> ~/.ssh/authorized_keys
+```
+
+## Adding a repository
+
+You should now be able to log into your host as the `git` user with using `<git-key>`.
+Setting up the route from client to server is half the work.
+
+Next step, to make this actually server a Git repository, is to create one.
+All this requires is a bare Git repository somewhere within `/srv/git`.
+To do this, log in as the `git` user and run:
+```sh
+git init --bare <repo-name>.git
+```
+
+That's it.
+
+You now have a Git "server" with a repo named `<repo-name>`.
+
+To add something to this repo, on your client machine create a new repository and add `<host>:/srv/git/<repo-name>.git` as remote and push your project to it.
+Common practice dictates that this remote be called `origin`:
+```sh
+mkdir my-fancy-project
+cd my-fancy-project
+git init
+git remote add origin <host>:/srv/git/<repo-name>.git
+echo "# Self-hosted repo!" > README.md
+git add -A
+git commit -m "Initial commit"
+git push -u origin main # assuming you use main as your default branch name
+```
+
+To clone this repository on another machine, add the `<git-key>` SSH keypair and related configuration section in `~/.ssh/config` so said machine and run:
+```sh
+git clone <host>:/srv/git/<repo-name>.git
+```
+
+# Automation
+
+Creating bare repositories by hand gets annoying quite quickly.
+I have an SSH forced command for another key that runs a script with the following:
+```sh
+#!/bin/sh
+
+BASELOC="/srv/git"
+echo "Enter new repo name:"
+read REPONAME
+[ -z $REPONAME ] && echo "No repo initialised" && exit 1
+git init --bare $BASELOC/$REPONAME.git
+```
+`authorized_keys` entry for `git` user:
+
+```authorized_keys
+command="/srv/git/.bin/new-repo" ssh-ed25519 <new-repo-git-key>.pub
+```
+
+Another thing you could do is change the login shell binary to a script that does something similar.
+I haven't bothered to do so for reasons that presently escape me.