From 3bdc986dd7e5e721089ab1a49981db52e3387272 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Mon, 4 Sep 2023 21:17:52 +0100
Subject: [PATCH] extract "mount filesystem" to module

---
 THOUGHTS.txt              |  4 ++--
 examples/arhcive.nix      | 20 +++++-----------
 modules/mount/default.nix | 49 +++++++++++++++++++++++++++++++++++++++
 modules/mount/service.nix | 18 ++++++++++++++
 4 files changed, 75 insertions(+), 16 deletions(-)
 create mode 100644 modules/mount/default.nix
 create mode 100644 modules/mount/service.nix

diff --git a/THOUGHTS.txt b/THOUGHTS.txt
index 85a46b4b..c6c9f8cb 100644
--- a/THOUGHTS.txt
+++ b/THOUGHTS.txt
@@ -2141,8 +2141,8 @@ Thu Aug 31 23:53:54 BST 2023
   - packet forwarding
 - and arhcive
   - rsync
-  - watchdog
-  - mount
+  - [done] watchdog
+  - [done] mount
 - nftables syntax error
 - tidy up the dependency handling in serviceDefn build
    (interface is fine, implementation is a bit brutal)
diff --git a/examples/arhcive.nix b/examples/arhcive.nix
index b5430a74..506b8bb8 100644
--- a/examples/arhcive.nix
+++ b/examples/arhcive.nix
@@ -30,6 +30,7 @@ in rec {
     ../modules/vlan
     ../modules/ssh
     ../modules/watchdog
+    ../modules/mount
   ];
 
   hostname = "arhcive";
@@ -101,27 +102,18 @@ in rec {
   };
 
   programs.busybox  = {
-    applets = ["blkid" "lsusb" "findfs" "tar"];
+    applets = ["lsusb" "tar"];
     options = {
       FEATURE_LS_TIMESTAMPS = "y";
       FEATURE_LS_SORTFILES = "y";
-      FEATURE_BLKID_TYPE = "y";
-      FEATURE_MOUNT_FLAGS = "y";
-      FEATURE_MOUNT_LABEL = "y";
       FEATURE_VOLUMEID_EXT = "y";
     };
   };
 
-  services.mount_external_disk = oneshot {
-    name = "mount_external_disk";
-    up = ''
-      while ! findfs LABEL=backup-disk; do
-        echo waiting for backup-disk
-        sleep 1
-      done
-      mount -t ext4 LABEL=backup-disk /srv
-    '';
-    down = "umount /srv";
+  services.mount_external_disk = svc.mount.build {
+    device = "LABEL=backup-disk";
+    mountpoint = "/srv";
+    fstype = "ext4";
   };
 
   services.rsync =
diff --git a/modules/mount/default.nix b/modules/mount/default.nix
new file mode 100644
index 00000000..31d5c450
--- /dev/null
+++ b/modules/mount/default.nix
@@ -0,0 +1,49 @@
+
+{ lib, pkgs, config, ...}:
+let
+  inherit (lib) mkOption types;
+  inherit (pkgs) liminix;
+  mkBoolOption = description : mkOption {
+    type = types.bool;
+    inherit description;
+    default = true;
+  };
+
+in {
+  options = {
+    system.service.mount = mkOption {
+      type = liminix.lib.types.serviceDefn;
+    };
+  };
+  config.system.service = {
+    mount = liminix.callService ./service.nix {
+      device = mkOption {
+        type = types.str;
+        example = "/dev/sda1";
+      };
+      mountpoint = mkOption {
+        type = types.str;
+        example = "/mnt/media";
+      };
+      options = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        example = ["noatime" "ro" "sync"];
+      };
+      fstype = mkOption {
+        type = types.str;
+        default = "auto";
+        example = "vfat";
+      };
+    };
+  };
+  config.programs.busybox  = {
+    applets = ["blkid" "findfs"];
+    options = {
+      FEATURE_BLKID_TYPE = "y";
+      FEATURE_MOUNT_FLAGS = "y";
+      FEATURE_MOUNT_LABEL = "y";
+      FEATURE_VOLUMEID_EXT = "y";
+    };
+  };
+}
diff --git a/modules/mount/service.nix b/modules/mount/service.nix
new file mode 100644
index 00000000..67fa7682
--- /dev/null
+++ b/modules/mount/service.nix
@@ -0,0 +1,18 @@
+{
+  liminix
+, lib
+}:
+{ device, mountpoint, options, fstype }:
+let
+  inherit (liminix.services) oneshot;
+in oneshot {
+  name = "mount.${lib.escapeURL mountpoint}";
+  up = ''
+    while ! findfs ${device}; do
+      echo waiting for device ${device}
+      sleep 1
+    done
+    mount -t ${fstype} -o ${lib.concatStringsSep "," options} ${device} ${mountpoint}
+  '';
+  down = "umount ${mountpoint}";
+}