nixpkgs/nixos/modules/services/misc/docker-registry.nix

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

with lib;

let
  cfg = config.services.dockerRegistry;

  configFile = pkgs.writeText "docker-registry-config.yml" (builtins.toJSON (recursiveUpdate registryConfig cfg.extraConfig));

in {
  options.services.dockerRegistry = {
    enable = mkEnableOption "Docker Registry";

    listenAddress = mkOption {
      description = "Docker registry host or ip to bind to.";
      default = "127.0.0.1";
      type = types.str;
    };

    port = mkOption {
      description = "Docker registry port to bind to.";
      default = 5000;
      type = types.int;
    };

    storagePath = mkOption {
      type = types.path;
      default = "/var/lib/docker-registry";
      description = "Docker registry storage path.";
    };

    enableDelete = mkOption {
      type = types.bool;
      default = false;
      description = "Enable delete for manifests and blobs.";
    };

    enableRedisCache = mkEnableOption "redis as blob cache";

    redisUrl = mkOption {
      type = types.str;
      default = "localhost:6379";
      description = "Set redis host and port.";
    };

    redisPassword = mkOption {
      type = types.str;
      default = "";
      description = "Set redis password.";
    };

    extraConfig = mkOption {
      description = ''
        Docker extra registry configuration via environment variables.
      '';
      default = {};
      type = types.attrs;
    };

    enableGarbageCollect = mkEnableOption "garbage collect";

    garbageCollectDates = mkOption {
      default = "daily";
      type = types.str;
      description = ''
        Specification (in the format described by
        <citerefentry><refentrytitle>systemd.time</refentrytitle>
        <manvolnum>7</manvolnum></citerefentry>) of the time at
        which the garbage collect will occur.
      '';
    };
  };

  config = mkIf cfg.enable {
    systemd.services.docker-registry = {
      description = "Docker Container Registry";
      wantedBy = [ "multi-user.target" ];
      after = [ "network.target" ];
      script = ''
        ${pkgs.docker-distribution}/bin/registry serve ${configFile}
      '';

      serviceConfig = {
        User = "docker-registry";
        WorkingDirectory = cfg.storagePath;
        AmbientCapabilities = mkIf (cfg.port < 1024) "cap_net_bind_service";
      };
    };

    systemd.services.docker-registry-garbage-collect = {
      description = "Run Garbage Collection for docker registry";

      restartIfChanged = false;
      unitConfig.X-StopOnRemoval = false;

      serviceConfig.Type = "oneshot";

      script = ''
        ${pkgs.docker-distribution}/bin/registry garbage-collect ${configFile}
        ${pkgs.systemd}/bin/systemctl restart docker-registry.service
      '';

      startAt = optional cfg.enableGarbageCollect cfg.garbageCollectDates;
    };

    users.users.docker-registry = {
      createHome = true;
      home = cfg.storagePath;
    };
  };
}