rclone: declarative mounts (#7060)

modules/programs/rclone.nix

@@ -9,6 +9,7 @@ let
 
   cfg = config.programs.rclone;
   iniFormat = pkgs.formats.ini { };
+  replaceSlashes = builtins.replaceStrings [ "/" ] [ "." ];
 
 in
 {
@@ -87,6 +88,80 @@ in
                     api_key = config.age.secrets.api-key.path;
                   }'';
               };
+
+              mounts = lib.mkOption {
+                type =
+                  with lib.types;
+                  attrsOf (
+                    lib.types.submodule {
+                      options = {
+                        enable = lib.mkEnableOption "this mount";
+
+                        mountPoint = lib.mkOption {
+                          type = lib.types.str;
+                          default = null;
+                          description = ''
+                            A local file path specifying the location of the mount point.
+                          '';
+                          example = "/home/alice/my-remote";
+                        };
+
+                        options = lib.mkOption {
+                          type =
+                            with lib.types;
+                            attrsOf (
+                              nullOr (oneOf [
+                                bool
+                                int
+                                float
+                                str
+                              ])
+                            );
+                          default = { };
+                          apply = lib.mergeAttrs {
+                            vfs-cache-mode = "full";
+                            cache-dir = "%C";
+                          };
+                          description = ''
+                            An attribute set of option values passed to `rclone mount`. To set
+                            a boolean option, assign it `true` or `false`. See
+                            <https://nixos.org/manual/nixpkgs/stable/#function-library-lib.cli.toGNUCommandLineShell>
+                            for more details on the format.
+
+                            Some caching options are set by default, namely `vfs-cache-mode = "full"`
+                            and `cache-dir`. These can be overridden if desired.
+                          '';
+                        };
+                      };
+                    }
+                  );
+                default = { };
+                description = ''
+                  An attribute set mapping remote file paths to their corresponding mount
+                  point configurations.
+
+                  For each entry, to perform the equivalent of
+                  `rclone mount remote:path/to/files /path/to/local/mount` — as described in the
+                  rclone documentation <https://rclone.org/commands/rclone_mount/> — we create
+                  a key-value pair like this:
+                  `"path/to/files/on/remote" = { ... }`.
+                '';
+                example = lib.literalExpression ''
+                  {
+                    "path/to/files" = {
+                      enable = true;
+                      mountPoint = "/home/alice/rclone-mount";
+                      options = {
+                        dir-cache-time = "5000h";
+                        poll-interval = "10s";
+                        umask = "002";
+                        user-agent = "Laptop";
+                      };
+                    };
+                  }
+                '';
+
+              };
             };
           }
         );
@@ -164,6 +239,56 @@ in
           ''
         );
     };
+
+    systemd.user.services = lib.listToAttrs (
+      lib.concatMap
+        (
+          { name, value }:
+          let
+            remote-name = name;
+            remote = value;
+          in
+          lib.concatMap (
+            { name, value }:
+            let
+              mount-path = name;
+              mount = value;
+            in
+            [
+              (lib.nameValuePair "rclone-mount:${replaceSlashes mount-path}@${remote-name}" {
+                Unit = {
+                  Description = "Rclone FUSE daemon for ${remote-name}:${mount-path}";
+                };
+
+                Service = {
+                  Environment = [
+                    # fusermount/fusermount3
+                    "PATH=/run/wrappers/bin"
+                  ];
+                  ExecStartPre = "${pkgs.coreutils}/bin/mkdir -p ${mount.mountPoint}";
+                  ExecStart = lib.concatStringsSep " " [
+                    (lib.getExe cfg.package)
+                    "mount"
+                    "-vv"
+                    (lib.cli.toGNUCommandLineShell { } mount.options)
+                    "${remote-name}:${mount-path}"
+                    "${mount.mountPoint}"
+                  ];
+                  Restart = "on-failure";
+                };
+
+                Install.WantedBy = [ "default.target" ];
+              })
+            ]
+          ) (lib.attrsToList remote.mounts)
+        )
+        (
+          lib.pipe cfg.remotes [
+            lib.attrsToList
+            (lib.filter (rem: rem.value ? mounts))
+          ]
+        )
+    );
   };
 
   meta.maintainers = with lib.hm.maintainers; [ jess ];

tests/integration/standalone/rclone/default.nix

@@ -1,20 +1,36 @@
 { pkgs, ... }:
 
+let
+  sshKeys = import "${pkgs.path}/nixos/tests/ssh-keys.nix" pkgs;
+
+  baseMachine = extend: {
+    imports = [
+      "${pkgs.path}/nixos/modules/installer/cd-dvd/channel.nix"
+      extend
+    ];
+    virtualisation.memorySize = 2048;
+    users.users.alice = {
+      isNormalUser = true;
+      description = "Alice Foobar";
+      password = "foobar";
+      uid = 1000;
+    };
+  };
+in
 {
   name = "rclone";
 
-  nodes.machine =
-    { ... }:
-    {
-      imports = [ "${pkgs.path}/nixos/modules/installer/cd-dvd/channel.nix" ];
-      virtualisation.memorySize = 2048;
-      users.users.alice = {
-        isNormalUser = true;
-        description = "Alice Foobar";
-        password = "foobar";
-        uid = 1000;
-      };
+  nodes = {
+    machine = baseMachine { };
+
+    remote = baseMachine {
+      services.openssh.enable = true;
+
+      users.users.alice.openssh.authorizedKeys.keys = [
+        sshKeys.snakeOilEd25519PublicKey
+      ];
     };
+  };
 
   testScript = ''
     start_all()
@@ -36,8 +52,13 @@
     def alice_cmd(cmd):
       return f"su -l alice --shell /bin/sh -c $'export XDG_RUNTIME_DIR=/run/user/$UID ; {cmd}'"
 
-    def succeed_as_alice(*cmds):
-      return machine.succeed(*map(alice_cmd,cmds))
+    def succeed_as_alice(*cmds, box=machine):
+      return box.succeed(*map(alice_cmd,cmds))
+
+    def systemctl_succeed_as_alice(cmd):
+      status, out = machine.systemctl(cmd, "alice")
+      assert status == 0, f"failed to run systemctl {cmd}"
+      return out
 
     def fail_as_alice(*cmds):
       return machine.fail(*map(alice_cmd,cmds))
@@ -101,6 +122,65 @@
 
     # TODO: verify correct activation order with the agenix and sops hm modules
 
+    remote.wait_for_unit("network.target")
+    remote.wait_for_unit("multi-user.target")
+
+    with subtest("Mount a remote (sftp)"):
+      # https://rclone.org/commands/rclone_mount/#vfs-directory-cache
+      # Sending a SIGHUP evicts every dcache entry
+      def clear_vfs_dcache():
+        svc_name = "rclone-mount:.home.alice.files@alices-sftp-remote.service"
+        succeed_as_alice(f"kill -s HUP $(systemctl --user show -p MainPID --value {svc_name})")
+        succeed_as_alice(
+          "sync",
+          "sleep 5",
+          box=remote
+        )
+
+      succeed_as_alice(
+        "mkdir -p /home/alice/.ssh",
+        "install -m644 ${./mount.nix} /home/alice/.config/home-manager/test-remote.nix"
+      )
+
+      actual = succeed_as_alice("home-manager switch")
+      expected = "Activating createRcloneConfig"
+      assert expected in actual, \
+        f"expected home-manager switch to contain {expected}, but got {actual}"
+
+      # remote -> machine
+      succeed_as_alice(
+        "mkdir /home/alice/files",
+        "touch /home/alice/files/test",
+        "echo started > /home/alice/files/log",
+        box=remote
+      )
+
+      succeed_as_alice("ls /home/alice/remote-files/test")
+
+      test_log = succeed_as_alice("cat /home/alice/remote-files/log")
+      expected = "started";
+      assert expected in test_log, \
+        f"Mounted file does not have expected contents. Expected {test_log} to contain \"{expected}\""
+
+      # machine -> remote
+      succeed_as_alice(
+        "touch /home/alice/remote-files/new-file",
+        "echo testing this works both ways! >> /home/alice/remote-files/log",
+      )
+
+      clear_vfs_dcache()
+
+      succeed_as_alice("ls /home/alice/files/new-file", box=remote)
+
+      test_log = succeed_as_alice("cat /home/alice/files/log", box=remote)
+      expected = "testing this works both ways!"
+      assert expected in test_log, \
+        f"Mounted file does not have expected contents. Expected {test_log} to contain \"{expected}\""
+
+      expected = "started"
+      assert expected in test_log, \
+        f"Mounted file does not have expected contents. Expected {test_log} to contain \"{expected}\""
+
     logout_alice()
   '';
 }

tests/integration/standalone/rclone/mount.nix

@@ -0,0 +1,27 @@
+{ pkgs, lib, ... }:
+let
+  sshKeys = import "${pkgs.path}/nixos/tests/ssh-keys.nix" pkgs;
+in
+{
+  programs.rclone.remotes = {
+    alices-sftp-remote = {
+      config = {
+        type = "sftp";
+        host = "remote";
+        user = "alice";
+        # https://rclone.org/sftp/#ssh-authentication
+        key_pem = lib.pipe sshKeys.snakeOilEd25519PrivateKey.text [
+          lib.trim
+          (lib.replaceStrings [ "\n" ] [ "\\n" ])
+        ];
+        known_hosts = sshKeys.snakeOilEd25519PublicKey;
+      };
+      mounts = {
+        "/home/alice/files" = {
+          enable = true;
+          mountPoint = "/home/alice/remote-files";
+        };
+      };
+    };
+  };
+}