homelab/services/dev/gitea.nix

{ config, lib, pkgs, ... }:

# Gitea — self-hosted git. stateDir/repositories were migrated from the old
# ZimaOS docker instance straight into stateDir's default layout, so no
# import step is needed — just chown it to the gitea user after first deploy
# (currently darman:users from the CIFS copy):
#   chown -R gitea:gitea /mnt/data/AppData/gitea
#
# HTTP is reverse-proxied through Caddy (hosts/jupiter/configuration.nix).
# SSH uses gitea's own built-in server on :2222 (not the host's :22, and not
# :222 — the unpriv gitea user can't bind <1024).
let
  # Repos where the ci-bot account (see below) should be a Write collaborator
  # and whitelisted to push past branch protection. Add a repo here and
  # redeploy — no manual UI clicking needed.
  ciBotRepos = [ "darman/hypr-chrome" ];
in
{
  services.gitea = {
    enable = true;
    stateDir = "/mnt/data/AppData/gitea";
    lfs.enable = true;

    settings = {
      repository = {
        DEFAULT_BRANCH = "master";
      };
      server = {
        DOMAIN = "git.mgaction.town";
        SSH_DOMAIN = "git.mgaction.town";
        # https, not http: neptun's Caddy terminates TLS for this name. Gitea
        # builds its absolute URLs (clone buttons, redirects, webhooks) from
        # ROOT_URL, so an http:// value hands out downgraded links.
        ROOT_URL = "https://git.mgaction.town/";
        HTTP_PORT = 3000;
        START_SSH_SERVER = true;
        SSH_PORT = 2222;
        SSH_LISTEN_PORT = 2222;
      };
      service = {
        DISABLE_REGISTRATION = true;
      };
      actions = {
        ENABLED = true;
      };
    };
  };

  networking.firewall.allowedTCPPorts = [ 2222 ];

  users.users.gitea.extraGroups = [ "users" ];

  # Runner instance registered against this same gitea. Jobs run in containers
  # (podman, via services/containers.nix — already enabled on jupiter), one
  # image per requested `runs-on` label using the catthehacker act-compatible
  # images (same ones upstream `act`/Forgejo docs recommend).
  #
  # tokenFile points at an env file rendered by sops (TOKEN=<registration
  # token>, see hosts/jupiter/secrets.nix) rather than a plain `token`, so the
  # secret never lands in the Nix store. The registration token itself is NOT
  # generated by this module — it comes from gitea once Actions is enabled:
  #   su gitea -s /bin/sh -c \
  #     'GITEA_WORK_DIR=/mnt/data/AppData/gitea gitea actions generate-runner-token'
  # then written into secrets/jupiter.yaml as gitea_runner_token.
  services.gitea-actions-runner.instances.jupiter = {
    enable = true;
    name = "jupiter";
    url = "https://git.mgaction.town/";
    tokenFile = config.sops.templates."gitea-runner.env".path;
    labels = [
      "ubuntu-latest:docker://ghcr.io/catthehacker/ubuntu:act-latest"
      "ubuntu-22.04:docker://ghcr.io/catthehacker/ubuntu:act-22.04"
    ];
  };

  # ci-bot: dedicated account CI workflows push as (kept separate from any
  # human account so its own PAT can be scoped/rotated/revoked independently).
  # Collaborator access + branch-protection push-whitelisting have no CLI or
  # config-file surface in gitea — only the HTTP API — so this is the one
  # part of the setup that stays imperative even though it's nix-triggered:
  # a oneshot that PUTs/PATCHes the API into the desired state on every
  # deploy where its script changed (adding a repo to `ciBotRepos` and
  # redeploying is enough to pick it up; it won't self-heal a manual revert
  # done via the web UI unless the unit is also restarted).
  #
  # Auth for those API calls is darman's OWN token (named
  # "jupiter-ci-bot-provisioning" in gitea, scopes write:repository +
  # write:user — see hosts/jupiter/secrets.nix), since darman owns the repos
  # in ciBotRepos and only an owner-scoped token clears the reqOwnerCheck on
  # the collaborator/branch-protection endpoints; write:user is additionally
  # needed to push ci-bot's token below as a secret on darman's own account.
  # It is NOT ci-bot's own push token — ci-bot can't grant itself access.
  #
  # ci-bot's own push token (separate secret, ci_bot_token) is generated
  # once via:
  #   su gitea -s /bin/sh -c \
  #     'GITEA_WORK_DIR=/mnt/data/AppData/gitea gitea admin user generate-access-token \
  #      --username ci-bot --scopes write:repository'
  # and this service pushes it into gitea itself as a user-level Actions
  # secret (CI_BOT_TOKEN, on darman's account — see the PUT below) so
  # workflows in ciBotRepos can push as ci-bot without a per-repo secret.
  systemd.services.gitea-ci-bot-provision = {
    description = "Provision ci-bot gitea account + repo access";
    after = [ "gitea.service" ];
    requires = [ "gitea.service" ];
    wantedBy = [ "multi-user.target" ];
    path = [ pkgs.curl pkgs.jq config.services.gitea.package ];
    environment = {
      TOKEN_FILE = config.sops.secrets.gitea_provisioning_token.path;
      CI_BOT_TOKEN_FILE = config.sops.secrets.gitea_ci_bot_token.path;
    };
    serviceConfig = {
      Type = "oneshot";
      RemainAfterExit = true;
      User = config.services.gitea.user;
    };
    script = ''
      set -euo pipefail
      api=http://127.0.0.1:${toString config.services.gitea.settings.server.HTTP_PORT}/api/v1
      admin_token="$(cat "$TOKEN_FILE")"
      auth=(-H "Authorization: token $admin_token")

      for _ in $(seq 1 30); do
        curl -fs "$api/version" >/dev/null 2>&1 && break
        sleep 1
      done

      if ! curl -fs "''${auth[@]}" "$api/users/ci-bot" >/dev/null 2>&1; then
        GITEA_WORK_DIR=${config.services.gitea.stateDir} gitea admin user create \
          --username ci-bot \
          --email ci-bot@${config.services.gitea.settings.server.DOMAIN} \
          --random-password --must-change-password=false
      fi

      # No instance-wide secret scope exists in Gitea (it's an open feature
      # request) - a user-level secret on darman's own account is the closest
      # equivalent, since every repo below is owned directly by darman, not
      # an org, and repo-level secrets fall back to user-level when unset.
      ci_bot_token="$(cat "$CI_BOT_TOKEN_FILE")"
      curl -fsS "''${auth[@]}" -H 'Content-Type: application/json' \
        -X PUT "$api/user/actions/secrets/CI_BOT_TOKEN" \
        -d "$(jq -n --arg data "$ci_bot_token" '{data: $data}')"

      ${lib.concatMapStringsSep "\n" (repo: ''
        curl -fsS "''${auth[@]}" -H 'Content-Type: application/json' \
          -X PUT "$api/repos/${repo}/collaborators/ci-bot" \
          -d '{"permission":"write"}'

        default_branch="$(curl -fs "''${auth[@]}" "$api/repos/${repo}" | jq -r .default_branch)"

        # ci-bot needs push access on every branch a workflow might commit
        # back to (currently just `develop`, where version-bump.yml pushes),
        # in addition to whatever the repo's actual default branch is.
        branches="$(printf '%s\n' "$default_branch" develop | sort -u)"
        for branch in $branches; do
          if curl -fs "''${auth[@]}" "$api/repos/${repo}/branch_protections/$branch" >/dev/null 2>&1; then
            curl -fsS "''${auth[@]}" -H 'Content-Type: application/json' \
              -X PATCH "$api/repos/${repo}/branch_protections/$branch" \
              -d '{"enable_push":true,"enable_push_whitelist":true,"push_whitelist_usernames":["ci-bot"]}'
          else
            curl -fsS "''${auth[@]}" -H 'Content-Type: application/json' \
              -X POST "$api/repos/${repo}/branch_protections" \
              -d "{\"branch_name\":\"$branch\",\"enable_push\":true,\"enable_push_whitelist\":true,\"push_whitelist_usernames\":[\"ci-bot\"]}"
          fi
        done
      '') ciBotRepos}
    '';
  };
}