feat(colmena): add git-daemon

2 files changed, 146 insertions, 0 deletions

diff --git a/colmena/cobalt/modules/git-daemon.nix b/colmena/cobalt/modules/git-daemon.nix
new file mode 100644
index 0000000..76b395e
--- /dev/null
+++ b/colmena/cobalt/modules/git-daemon.nix
@@ -0,0 +1,137 @@
+{ config, lib, pkgs, ... }:
+with lib;
+let
+
+  cfg = config.services.gitDaemon;
+
+in
+{
+
+  ###### interface
+
+  options = {
+    services.gitDaemon = {
+
+      enable = mkOption {
+        type = types.bool;
+        default = false;
+        description = lib.mdDoc ''
+          Enable Git daemon, which allows public hosting of git repositories
+          without any access controls. This is mostly intended for read-only access.
+
+          You can allow write access by setting daemon.receivepack configuration
+          item of the repository to true. This is solely meant for a closed LAN setting
+          where everybody is friendly.
+
+          If you need any access controls, use something else.
+        '';
+      };
+
+      basePath = mkOption {
+        type = types.str;
+        default = "";
+        example = "/srv/git/";
+        description = lib.mdDoc ''
+          Remap all the path requests as relative to the given path. For example,
+          if you set base-path to /srv/git, then if you later try to pull
+          git://example.com/hello.git, Git daemon will interpret the path as /srv/git/hello.git.
+        '';
+      };
+
+      exportAll = mkOption {
+        type = types.bool;
+        default = false;
+        description = lib.mdDoc ''
+          Publish all directories that look like Git repositories (have the objects
+          and refs subdirectories), even if they do not have the git-daemon-export-ok file.
+
+          If disabled, you need to touch .git/git-daemon-export-ok in each repository
+          you want the daemon to publish.
+
+          Warning: enabling this without a repository whitelist or basePath
+          publishes every git repository you have.
+        '';
+      };
+
+      repositories = mkOption {
+        type = types.listOf types.str;
+        default = [ ];
+        example = [ "/srv/git" "/home/user/git/repo2" ];
+        description = lib.mdDoc ''
+          A whitelist of paths of git repositories, or directories containing repositories
+          all of which would be published. Paths must not end in "/".
+
+          Warning: leaving this empty and enabling exportAll publishes all
+          repositories in your filesystem or basePath if specified.
+        '';
+      };
+
+      listenAddress = mkOption {
+        type = types.str;
+        default = "";
+        example = "example.com";
+        description = lib.mdDoc "Listen on a specific IP address or hostname.";
+      };
+
+      port = mkOption {
+        type = types.port;
+        default = 9418;
+        description = lib.mdDoc "Port to listen on.";
+      };
+
+      options = mkOption {
+        type = types.str;
+        default = "";
+        description = lib.mdDoc "Extra configuration options to be passed to Git daemon.";
+      };
+
+      user = mkOption {
+        type = types.str;
+        default = "git";
+        description = lib.mdDoc "User under which Git daemon would be running.";
+      };
+
+      group = mkOption {
+        type = types.str;
+        default = "git";
+        description = lib.mdDoc "Group under which Git daemon would be running.";
+      };
+
+      createUserAndGroup = mkOption {
+        type = types.bool;
+        default = true;
+        description = lib.mdDoc ''
+          Create the specified group and user.
+          Disable this option if you want to use the existing user
+        '';
+      };
+    };
+  };
+
+  ###### implementation
+
+  config = mkIf cfg.enable {
+
+    users.users.${cfg.user} = optionalAttrs (cfg.createUserAndGroup == true) {
+      uid = config.ids.uids.git;
+      group = cfg.group;
+      description = "Git daemon user";
+    };
+
+    users.groups.${cfg.group} = optionalAttrs (cfg.createUserAndGroup == true) {
+      gid = config.ids.gids.git;
+    };
+
+    systemd.services.git-daemon = {
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+      script = "${pkgs.git}/bin/git daemon --reuseaddr "
+        + (optionalString (cfg.basePath != "") "--base-path=${cfg.basePath} ")
+        + (optionalString (cfg.listenAddress != "") "--listen=${cfg.listenAddress} ")
+        + "--port=${toString cfg.port} --user=${cfg.user} --group=${cfg.group} ${cfg.options} "
+        + "--verbose " + (optionalString cfg.exportAll "--export-all ") + concatStringsSep " " cfg.repositories;
+    };
+
+  };
+
+}
diff --git a/colmena/cobalt/services/git-daemon.nix b/colmena/cobalt/services/git-daemon.nix
index 4ba73cf..f0dbad6 100644
--- a/colmena/cobalt/services/git-daemon.nix
+++ b/colmena/cobalt/services/git-daemon.nix
@@ -1,6 +1,15 @@
 {
   services.gitDaemon = {
       enable = true;
+      createUserAndGroup = false;
       basePath = "/var/lib/gitolite/repositories";
   };
+
+  networking.firewall.allowedTCPPorts = [ 9418 ];
+
+  disabledModules = [ "services/networking/git-daemon.nix" ];
+
+  imports = [
+    ../modules/git-daemon.nix
+  ];
 }