nixos-restic/flake.nix

{
  description = "Restic";

  inputs = {
    nixpkgs = {
      url = "nixpkgs/nixos-23.11";
    };
    flake-utils = {
      url = "github:numtide/flake-utils";
    };
  };
  outputs = {
    self,
    nixpkgs,
    flake-utils,
    ...
  } @ inputs:
    flake-utils.lib.eachDefaultSystem
    (
      system: let
        pkgs = import nixpkgs {
          inherit system;
        };
      in {
        packages = {
          restic = let
            pname = "restic";
            version = "0.16.4";
            hash = "sha256-TSUhrtSgGIPM/cUzA6WDtCpqCyjtnM5BZDhK6udR0Ek=";
            vendorHash = "sha256-E+Erf8AdlMBdep1g2SpI8JKIdJuKqmyWEUmh8Rs5R/o=";
          in
            pkgs.buildGoModule {
              inherit pname version vendorHash;

              src = pkgs.fetchFromGitHub {
                owner = "restic";
                repo = "restic";
                rev = "v${version}";
                hash = hash;
              };

              env = {
                RESTIC_TEST_FUSE = "false";
              };

              patches = [
                # The TestRestoreWithPermissionFailure test fails in Nix's build sandbox
                ./0001-Skip-testing-restore-with-permission-failure.patch
              ];

              subPackages = ["cmd/restic"];

              nativeBuildInputs = [
                pkgs.installShellFiles
                pkgs.makeWrapper
              ];

              passthru.tests.restic = pkgs.nixosTests.restic;

              postPatch = ''
                # rm cmd/restic/integration_fuse_test.go
              '';

              postInstall =
                ''
                  wrapProgram $out/bin/restic --prefix PATH : '${pkgs.rclone}/bin'
                ''
                + pkgs.lib.optionalString (pkgs.stdenv.hostPlatform == pkgs.stdenv.buildPlatform) ''
                  $out/bin/restic generate \
                    --bash-completion restic.bash \
                    --fish-completion restic.fish \
                    --zsh-completion restic.zsh \
                    --man .
                  installShellCompletion restic.{bash,fish,zsh}
                  installManPage *.1
                '';

              meta = with pkgs.lib; {
                homepage = "https://restic.net";
                description = "A backup program that is fast, efficient and secure";
                platforms = platforms.linux ++ platforms.darwin;
                license = licenses.bsd2;
                maintainers = [maintainers.mbrgm];
              };
            };

          entrypoint = pkgs.writeTextFile {
            name = "entrypoint";
            destination = "/bin/entrypoint";
            text = pkgs.lib.concatStringsSep "\n" [
              "#!${pkgs.nushell}/bin/nu"
              (builtins.readFile ./entrypoint.nu)
            ];
            executable = true;
          };

          docker = pkgs.dockerTools.buildLayeredImage {
            name = "restic";
            tag = "latest";
            maxLayers = 2;
            contents = [
            ];
            config = {
              Cmd = [
                "${self.packages.${system}.entrypoint}/bin/entrypoint"
                "--rclone"
                "${pkgs.rclone}/bin/rclone"
                "--restic"
                "${self.packages.${system}.restic}/bin/restic"
                "--cache-dir"
                "/cache"
              ];
              Env = [
                "TZ=UTC"
                "SSL_CERT_FILE=${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt"
              ];
              ExposedPorts = {};
              Volumes = {
                "/cache" = {};
              };
            };
          };
        };
      }
    )
    // {
      nixosModules = {
        restic = {
          config,
          lib,
          pkgs,
          ...
        }: let
          cfg = config.restic;
          package = self.packages.${pkgs.system}.restic;
        in {
          options = {
            restic = lib.options.mkOption {
              type = lib.types.submodule {
                options = {
                  enable = lib.options.mkEnableOption "Restic";
                  passwordFile = lib.options.mkOption {
                    type = lib.types.path;
                  };
                  storage = lib.options.mkOption {
                    type = lib.types.enum [
                      "azure"
                      "b2"
                    ];
                  };
                  healthcheck = lib.options.mkOption {
                    type = lib.types.submodule {
                      options = {
                        enable = lib.options.mkEnableOption "use healthcheck";
                        apiUrl = lib.options.mkOption {
                          type = lib.types.str;
                        };
                        apiKeyFile = lib.options.mkOption {
                          type = lib.types.str;
                        };
                        timeout = lib.options.mkOption {
                          type = lib.types.int;
                          default = 86400;
                        };
                        grace = lib.options.mkOption {
                          type = lib.types.int;
                          default = 14400;
                        };
                      };
                    };
                  };
                  b2 = lib.options.mkOption {
                    type = lib.types.submodule {
                      options = {
                        bucket = lib.options.mkOption {
                          type = lib.types.str;
                        };
                        accountId = lib.options.mkOption {
                          type = lib.types.str;
                        };
                        accountKeyFile = lib.options.mkOption {
                          type = lib.types.str;
                        };
                      };
                    };
                  };
                  azure = lib.options.mkOption {
                    type = lib.types.submodule {
                      options = {
                        accountName = lib.options.mkOption {
                          type = lib.types.str;
                        };
                        accountKeyFile = lib.options.mkOption {
                          type = lib.types.nullOr lib.types.str;
                          default = null;
                        };
                      };
                    };
                  };
                  backups = lib.options.mkOption {
                    type = lib.types.listOf (
                      lib.types.submodule {
                        options = {
                          oneFileSystem = lib.options.mkOption {
                            type = lib.types.bool;
                            default = false;
                          };
                          excludes = lib.options.mkOption {
                            type = lib.types.listOf lib.types.str;
                            default = [];
                          };
                          paths = lib.options.mkOption {
                            type = lib.types.listOf lib.types.str;
                            default = [];
                          };
                          preCommand = lib.options.mkOption {
                            type = lib.types.lines;
                            default = "";
                          };
                          postCommand = lib.options.mkOption {
                            type = lib.types.lines;
                            default = "";
                          };
                        };
                      }
                    );
                  };
                };
              };
            };
          };

          config = let
            bucket =
              {
                "b2" = cfg.b2.bucket;
                "azure" = builtins.replaceStrings ["."] ["-"] "${config.networking.hostName}.${config.networking.domain}";
              }
              .${cfg.storage};

            directory =
              {
                "b2" = "${config.networking.hostName}.${config.networking.domain}";
                "azure" = "/";
              }
              .${cfg.storage};
          in
            lib.mkIf cfg.enable {
              environment.systemPackages = [
                package
              ];

              systemd.services.restic = let
                curlOptions = "--fail --silent --show-error --max-time 10 --retry 5";
                hcPayload =
                  if cfg.healthcheck.enable
                  then
                    (
                      pkgs.writeText "healthcheck-payload"
                      (
                        builtins.toJSON
                        {
                          name = "${config.networking.hostName}.${config.networking.domain}";
                          timeout = cfg.healthcheck.timeout;
                          grace = cfg.healthcheck.grace;
                          unique = ["name"];
                          channels = "*";
                        }
                      )
                    )
                  else null;
                hcSetup =
                  if cfg.healthcheck.enable
                  then ''
                    HC_URL=''$(${pkgs.curl}/bin/curl ${curlOptions} --request POST --header 'Content-Type: application/json' --header "X-Api-Key: ''$(<${cfg.healthcheck.apiKeyFile})" --data @${hcPayload} "${cfg.healthcheck.apiUrl}" | ${pkgs.jq}/bin/jq -r .ping_url)
                  ''
                  else "";
                hcStart =
                  if cfg.healthcheck.enable
                  then ''
                    if [ ! -z "''${HC_URL}" ]
                    then
                      ${pkgs.curl}/bin/curl ${curlOptions} --output /dev/null "''${HC_URL}/start" || true
                    fi
                  ''
                  else "";
                hcStop =
                  if cfg.healthcheck.enable
                  then ''
                    if [ ! -z "''${HC_URL}" ]
                    then
                      ${pkgs.curl}/bin/curl ${curlOptions} --output /dev/null "''${HC_URL}" || true
                    fi
                  ''
                  else "";

                repositoryConfig =
                  {
                    "b2" = "b2:${bucket}:${directory}";
                    "azure" = "azure:${bucket}:${directory}";
                  }
                  .${cfg.storage};

                resticConfig =
                  ''
                    export RESTIC_CACHE_DIR=/var/cache/restic
                    export RESTIC_PASSWORD_FILE=${cfg.passwordFile}
                    export RESTIC_REPOSITORY=${repositoryConfig}
                  ''
                  + {
                    "b2" = ''
                      export B2_ACCOUNT_ID='${cfg.b2.accountId}'
                      export B2_ACCOUNT_KEY="''$(<${cfg.b2.accountKeyFile})"
                    '';
                    "azure" = ''
                      export AZURE_ACCOUNT_NAME='${cfg.azure.accountName}'
                      export AZURE_ACCOUNT_KEY="''$(<${cfg.azure.accountKeyFile})"
                    '';
                  }
                  .${cfg.storage};

                backupCommands =
                  lib.strings.concatStringsSep "\n"
                  (
                    map
                    (
                      backup: let
                        oneFileSystem =
                          if backup.oneFileSystem
                          then ["--one-file-system"]
                          else [];
                        excludes =
                          map
                          (
                            exclude: ''--exclude="${exclude}"''
                          )
                          backup.excludes;
                        paths =
                          map
                          (
                            path: ''"${path}"''
                          )
                          backup.paths;
                        arguments = lib.strings.concatStringsSep " " (
                          oneFileSystem ++ excludes ++ paths
                        );
                      in ''
                        ${backup.preCommand}
                        ${package}/bin/restic backup ${arguments}
                        ${backup.postCommand}
                      ''
                    )
                    cfg.backups
                  );
                initCheck =
                  {
                    "b2" = ''
                      export RCLONE_CONFIG=/dev/null
                      export RCLONE_CONFIG_B2_TYPE=b2
                      export RCLONE_CONFIG_B2_ACCOUNT='${cfg.b2.accountId}'
                      export RCLONE_CONFIG_B2_KEY="''$(<${cfg.b2.accountKeyFile})"

                      config=''$(${pkgs.rclone}/bin/rclone lsjson 'b2:${bucket}/${directory}/config' | ${pkgs.jq}/bin/jq -r '. | length | . > 0')

                      if [ "''${config}" != 'true' ]
                      then
                        ${package}/bin/restic init
                      fi
                    '';

                    "azure" = ''
                      export RCLONE_CONFIG=/dev/null
                      export RCLONE_CONFIG_AZURE_TYPE=azureblob
                      export RCLONE_CONFIG_AZURE_ACCOUNT='${cfg.azure.accountName}'
                      export RCLONE_CONFIG_AZURE_KEY="''$(<${cfg.azure.accountKeyFile})"

                      container=''$(${pkgs.rclone}/bin/rclone lsjson 'azure:' | ${pkgs.jq}/bin/jq -r 'map(select(.Path=="${bucket}" and .IsBucket)) | length | . > 0')

                      if [ "''${container}" != 'true' ]
                      then
                        ${pkgs.rclone}/bin/rclone mkdir 'azure:${bucket}'
                      fi

                      config=$(${pkgs.rclone}/bin/rclone lsjson 'azure:${bucket}/config' | ${pkgs.jq}/bin/jq -r '. | length | . > 0')

                      if [ "''${config}" != 'true' ]
                      then
                        ${package}/bin/restic init
                      fi
                    '';
                  }
                  .${cfg.storage};
              in {
                serviceConfig = {
                  Type = "oneshot";
                  CacheDirectory = "restic";
                };
                script = ''
                  ${hcSetup}
                  ${hcStart}

                  ${resticConfig}

                  ${initCheck}

                  ${backupCommands}

                  ${package}/bin/restic forget --prune --keep-daily 14
                  ${package}/bin/restic check
                  ${package}/bin/restic cache --cleanup

                  ${hcStop}
                '';
              };

              systemd.timers.restic = {
                timerConfig = {
                  OnCalendar = "*-*-* 02:00:00";
                  RandomizedDelaySec = "60m";
                };
                wantedBy = ["multi-user.target"];
              };
            };
        };
      };
    };
}