summary refs log tree commit diff stats
path: root/system/services/nix-sync/default.nix
blob: 18511b3e4795c21b67d52860adfc6c6aaa47cfdb (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
{
  config,
  lib,
  pkgs,
  ...
}: let
  cfg = config.services.nix-sync;

  mkUnit = name: repo: let
    esa = lib.strings.escapeShellArg;
    execStartScript = lib.writeShellScript "git-sync-exec" ''
      cd ${esa cfg.cachePath}/${esa repo.path};

      while true; do
        origin="$(git rev-parse @{u})";
        branch="$(git rev-parse @)";

        if ! [ "$origin" = "$branch" ]; then
          git pull;

          out_paths=$(mktemp);
          nix build . --print-out-paths --experimental-features 'nix-command flakes' > "$out_paths";
          [ "$(wc -l < "$out_paths")" -gt 1 ] && (echo "To many out-paths"; exit 1)
          out_path="$(cat "$out_paths")";
          rm -r ${esa repo.path};
          ln -s "$out_path" ${esa repo.path};
          rm "$out-paths";
        fi
        sleep ${esa repo.interval};
      done
    '';
    execStartPreScript = ''
      if ! stat ${esa cfg.cachePath}/${esa repo.path}/.git; then
          mkdir --parents ${esa cfg.cachePath}/${esa repo.path};
          git clone ${esa repo.uri} ${esa cfg.cachePath}/${esa repo.path};

          out_paths=$(mktemp);
          nix build ${esa cfg.cachePath}/${esa repo.path} --print-out-paths --experimental-features 'nix-command flakes' > "$out_paths";
          [ "$(wc -l < "$out_paths")" -gt 1 ] && (echo "To many out-paths"; exit 1)
          out_path="$(cat "$out_paths")";
          ln -s "$out_path" ${esa repo.path};
          rm "$out-paths";
      fi
    '';
  in {
    description = "Nix Sync ${name}";
    wantedBy = ["default.target"];
    after = ["network.target"];
    path = with pkgs; [openssh git nix mktemp coreutils];
    preStart = execStartPreScript;

    serviceConfig = {
      ExecStart = execStartScript;
      Restart = "on-abort";
      # User and group
      User = cfg.user;
      Group = cfg.group;
      # Runtime directory and mode
      RuntimeDirectory = "nginx";
      RuntimeDirectoryMode = "0750";
      # Cache directory and mode
      CacheDirectory = "nginx";
      CacheDirectoryMode = "0750";
      # Logs directory and mode
      LogsDirectory = "nginx";
      LogsDirectoryMode = "0750";
      # Proc filesystem
      ProcSubset = "pid";
      ProtectProc = "invisible";
      # New file permissions
      UMask = "0027"; # 0640 / 0750
      # Capabilities
      AmbientCapabilities = ["CAP_CHOWN"];
      CapabilityBoundingSet = ["CAP_CHOWN"];
      # Security
      NoNewPrivileges = true;
      # Sandboxing (sorted by occurrence in https://www.freedesktop.org/software/systemd/man/systemd.exec.html)
      ReadWritePaths = ["${repo.path}" "${cfg.cachePath}/${repo.path}"];
      ProtectSystem = "strict";
      ProtectHome = true;
      PrivateTmp = true;
      PrivateDevices = true;
      ProtectHostname = true;
      ProtectClock = true;
      ProtectKernelTunables = true;
      ProtectKernelModules = true;
      ProtectKernelLogs = true;
      ProtectControlGroups = true;
      RestrictAddressFamilies = ["AF_UNIX" "AF_INET" "AF_INET6"];
      RestrictNamespaces = true;
      LockPersonality = true;
      MemoryDenyWriteExecute = true;
      RestrictRealtime = true;
      RestrictSUIDSGID = true;
      RemoveIPC = true;
      PrivateMounts = true;
      # System Call Filtering
      SystemCallArchitectures = "native";
      SystemCallFilter = ["~@cpu-emulation @debug @keyring @mount @obsolete @privileged @setuid"];
    };
  };

  services =
    lib.mapAttrs' (name: repo: {
      name = "git-sync-${name}";
      value = mkUnit name repo;
    })
    cfg.repositories;

  repositoryType = lib.types.submodule ({name, ...}: {
    options = {
      name = lib.mkOption {
        internal = true;
        default = name;
        type = lib.types.str;
        description = "The name that should be given to this unit.";
      };

      path = lib.mkOption {
        type = lib.types.str;
        description = "The path at which to sync the repository";
      };

      uri = lib.mkOption {
        type = lib.types.str;
        example = "git+ssh://user@example.com:/~[user]/path/to/repo.git";
        description = ''
          The URI of the remote to be synchronized. This is only used in the
          event that the directory does not already exist. See
          <link xlink:href="https://git-scm.com/docs/git-clone#_git_urls"/>
          for the supported URIs.
        '';
      };

      interval = lib.mkOption {
        type = lib.types.int;
        default = 500;
        description = ''
          The interval, specified in seconds, at which the synchronization will
          be triggered even without filesystem changes.
        '';
      };
    };
  });
in {
  options = {
    services.git-sync = {
      enable = lib.mkEnableOption "git-sync services";

      package = lib.mkOption {
        type = lib.types.package;
        default = pkgs.git-sync;
        defaultText = lib.literalExpression "pkgs.git-sync";
        description = ''
          Package containing the <command>git-sync</command> program.
        '';
      };

      user = lib.mkOption {
        type = lib.types.str;
        default = "nix-sync";
        description = lib.mdDoc "User account under which nix-sync units runs.";
      };

      group = lib.mkOption {
        type = lib.types.str;
        default = "nix-sync";
        description = lib.mdDoc "Group account under which nix-sync units runs.";
      };

      cachePath = lib.mkOption {
        type = lib.types.str;
        default = "/var/lib/nix-sync";
        description = lib.mdDoc ''
          Where to cache git directories.
        '';
      };

      repositories = lib.mkOption {
        type = with lib.types; attrsOf repositoryType;
        description = ''
          The repositories that should be synchronized.
        '';
      };
    };
  };

  config = lib.mkIf cfg.enable {
    systemd.services = services;
  };
}
# vim: ts=2