From 0a5754541bb01e96021ca7ee74f1256a8ee68bc4 Mon Sep 17 00:00:00 2001
From: tdback <tyler@tdback.net>
Date: Sat, 21 Dec 2024 15:32:13 -0500
Subject: initial commit to self-hosted git

---
 modules/customs/cgit/default.nix | 134 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)
 create mode 100644 modules/customs/cgit/default.nix

(limited to 'modules/customs/cgit')

diff --git a/modules/customs/cgit/default.nix b/modules/customs/cgit/default.nix
new file mode 100644
index 0000000..19eac01
--- /dev/null
+++ b/modules/customs/cgit/default.nix
@@ -0,0 +1,134 @@
+{ config, lib, pkgs, ... }:
+with lib;
+let
+  cfg = config.services.cgit;
+
+  mkCgitrc = cfg:
+    pkgs.writeText "cgitrc" (let
+      cgitConfig = {
+        css = "/cgit.css";
+        logo = "/cgit.png";
+        favicon = "/favicon.ico";
+        about-filter = "${cfg.package}/lib/cgit/filters/about-formatting.sh";
+        source-filter = "${cfg.package}/lib/cgit/filters/syntax-highlighting.py";
+        enable-git-config = 1;
+        # Disable cgit's HTTP "dumb" protocol and use git itself to provide the
+        # HTTP "smart" protocol instead.
+        enable-http-clone = 0;
+        remove-suffix = 1;
+        clone-url = "https://${cfg.virtualHost}/$CGIT_REPO_URL.git";
+        scan-path = cfg.scanPath;
+      };
+    in
+      generators.toKeyValue { } (cfg.settings // cgitConfig)
+    );
+
+  mkCgitAssets = pkg: files:
+    builtins.map (f: ''
+      handle_path /${f} {
+        root * ${pkg}/cgit/${f}
+        file_server
+      }
+    '') files |> strings.concatStringsSep "\n";
+in
+{
+  disabledModules = [ "services/networking/cgit.nix" ];
+
+  options = {
+    services.cgit = {
+      enable = mkEnableOption "cgit";
+      package = mkPackageOption pkgs "cgit" { };
+      user = mkOption {
+        description = "User to run cgit service as";
+        type = types.str;
+        default = "git";
+      };
+      group = mkOption {
+        description = "Group to run cgit service as";
+        type = types.str;
+        default = "git";
+      };
+      scanPath = mkOption {
+        description = "A path which will be scanned for repositories";
+        type = types.path;
+        default = "/var/lib/cgit";
+      };
+      virtualHost = mkOption {
+        description = "Virtual host to serve cgit on";
+        type = types.str;
+        default = null;
+      };
+      authorizedKeys = mkOption {
+        description = "SSH keys for authorized git users";
+        type = types.listOf types.str;
+        default = [ ];
+      };
+      settings = mkOption {
+        description = "Additional cgit configuration. see cgitrc(5)";
+        type = with types; let settingType = oneOf [ bool int str ]; in
+          attrsOf (oneOf [
+            settingType
+            (listOf settingType)
+          ]);
+        default = { };
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    programs.git = {
+      enable = true;
+      config.init.defaultBranch = "main";
+    };
+
+    # Setup git user with git-shell for authenticated pushes.
+    users.users.${cfg.user} = {
+      isSystemUser = true;
+      home = cfg.scanPath;
+      group = cfg.group;
+      shell = "${pkgs.git}/bin/git-shell";
+      openssh.authorizedKeys.keys = cfg.authorizedKeys;
+    };
+
+    users.groups.${cfg.group} = {};
+
+    # Harden git user to prevent SSH port forwarding to other servers.
+    services.openssh = {
+      enable = true;
+      settings.AllowUsers = [ cfg.user ];
+      extraConfig = ''
+        Match user ${cfg.user}
+          AllowTCPForwarding no
+          AllowAgentForwarding no
+          PasswordAuthentication no
+          PermitTTY no
+          X11Forwarding no
+      '';
+    };
+
+    # Configure fcgiwrap instance for caddy to properly serve cgi scripts.
+    # Reference: https://github.com/NixOS/nixpkgs/blob/nixos-24.11/nixos/modules/services/networking/cgit.nix
+    services.fcgiwrap.instances.cgit = {
+      process = { inherit (cfg) user group; };
+      socket = { inherit (config.services.caddy) user group; };
+    };
+
+    services.caddy.virtualHosts.${cfg.virtualHost}.extraConfig =
+      let
+        socket = config.services.fcgiwrap.instances.cgit.socket.address;
+      in ''
+        encode zstd gzip
+
+        reverse_proxy unix/${socket} {
+          transport fastcgi {
+            env SCRIPT_FILENAME ${cfg.package}/cgit/cgit.cgi
+            env CGIT_CONFIG ${mkCgitrc cfg}
+          }
+        }
+
+        ${mkCgitAssets cfg.package [
+          "cgit.css" "cgit.png" "favicon.ico" "robots.txt"
+        ]}
+      '';
+  };
+}
-- 
cgit v1.2.3