lib: better formatting of generated shell output

example/complex.nix

@@ -5,35 +5,29 @@
         type = "disk";
         device = builtins.elemAt disks 0;
         content = {
-          type = "table";
+          type = "gpt";
-          format = "gpt";
+          partitions = {
-          partitions = [
+            ESP = {
-            {
-              name = "ESP";
               start = "1MiB";
               end = "128MiB";
-              fs-type = "fat32";
-              bootable = true;
               content = {
                 type = "filesystem";
                 format = "vfat";
                 mountpoint = "/boot";
               };
-            }
+            };
-          ];
+          };
         };
       };
       disk1 = {
         type = "disk";
         device = builtins.elemAt disks 1;
         content = {
-          type = "table";
+          type = "gpt";
-          format = "gpt";
+          partitions = {
-          partitions = [
+            luks = {
-            {
               start = "1M";
-              end = "100%";
+              size = "100%";
-              name = "luks";
               content = {
                 type = "luks";
                 name = "crypted1";
@@ -46,21 +40,19 @@
                   vg = "pool";
                 };
               };
-            }
+            };
-          ];
+          };
         };
       };
       disk2 = {
         type = "disk";
         device = builtins.elemAt disks 2;
         content = {
-          type = "table";
+          type = "gpt";
-          format = "gpt";
+          partitions = {
-          partitions = [
+            luks = {
-            {
               start = "1M";
-              end = "100%";
+              size = "100%";
-              name = "luks";
               content = {
                 type = "luks";
                 name = "crypted2";
@@ -73,8 +65,8 @@
                   vg = "pool";
                 };
               };
-            }
+            };
-          ];
+          };
         };
       };
     };
@@ -83,20 +75,18 @@
         type = "mdadm";
         level = 1;
         content = {
-          type = "table";
+          type = "gpt";
-          format = "gpt";
+          partitions = {
-          partitions = [
+            bla = {
-            {
-              name = "bla";
               start = "1MiB";
-              end = "100%";
+              size = "100%";
               content = {
                 type = "filesystem";
                 format = "ext4";
                 mountpoint = "/ext4_mdadm_lvm";
               };
-            }
+            };
-          ];
+          };
         };
       };
     };

lib/default.nix

@@ -98,6 +98,17 @@ let
       in
         iter 1 list;
 
+
+    /* indent takes a multiline string and indents it by 2 spaces starting on the second line
+
+       indent :: str -> str
+
+       Example:
+       indent "test\nbla"
+       => "test\n  bla"
+    */
+    indent = replaceStrings ["\n"] ["\n  "];
+
     /* A nix option type representing a json datastructure, vendored from nixpkgs to avoid dependency on pkgs */
     jsonType =
       let
@@ -203,10 +214,10 @@ let
         readOnly = true;
         type = lib.types.str;
         default = ''
-          ( # ${config.type} ${concatMapStringsSep " " (n: toString (config.${n} or "")) ["name" "device" "format" "mountpoint"]}
+          ( # ${config.type} ${concatMapStringsSep " " (n: toString (config.${n} or "")) ["name" "device" "format" "mountpoint"]} #
-            ${diskoLib.defineHookVariables { inherit config options; }}
+            ${diskoLib.indent (diskoLib.defineHookVariables { inherit config options; })}
             ${config.preCreateHook}
-            ${attrs.default}
+            ${diskoLib.indent attrs.default}
             ${config.postCreateHook}
           )
         '';
@@ -228,7 +239,10 @@ let
     */
     writeCheckedBash = { pkgs, checked ? false, noDeps ? false }: pkgs.writers.makeScriptWriter {
       interpreter = if noDeps then "/usr/bin/env bash" else "${pkgs.bash}/bin/bash";
-      check = lib.optionalString checked "${pkgs.shellcheck}/bin/shellcheck -e SC2034";
+      check = lib.optionalString checked (pkgs.writeScript "check" ''
+        set -efu
+        ${pkgs.shellcheck}/bin/shellcheck -e SC2034 "$1"
+      '');
     };
 
 

lib/types/gpt.nix

@@ -104,7 +104,8 @@ in
             --typecode=${toString partition._index}:${partition.type} \
             ${config.device}
           # ensure /dev/disk/by-path/..-partN exists before continuing
-          udevadm trigger --subsystem-match=block; udevadm settle
+          udevadm trigger --subsystem-match=block
+          udevadm settle
           ${lib.optionalString (partition.content != null) partition.content._create}
         '') sortedPartitions)}
 

lib/types/luks.nix

@@ -55,7 +55,9 @@
       inherit config options;
       default = ''
         cryptsetup -q luksFormat ${config.device} ${diskoLib.maybeStr config.keyFile} ${toString config.extraFormatArgs}
-        cryptsetup luksOpen ${config.device} ${config.name} ${toString config.extraOpenArgs} ${lib.optionalString (config.keyFile != null) "--key-file ${config.keyFile}"}
+        cryptsetup luksOpen ${config.device} ${config.name} \
+          ${toString config.extraOpenArgs} \
+          ${lib.optionalString (config.keyFile != null) "--key-file ${config.keyFile}"}
         ${lib.optionalString (config.content != null) config.content._create}
       '';
     };

lib/types/mdadm.nix

@@ -42,7 +42,8 @@
           --force \
           --homehost=any \
           "''${disk_devices[@]}"
-        udevadm trigger --subsystem-match=block; udevadm settle
+        udevadm trigger --subsystem-match=block
+        udevadm settle
         ${lib.optionalString (config.content != null) config.content._create}
       '';
     };

lib/types/table.nix

@@ -91,7 +91,8 @@
             parted -s ${config.device} -- mkpart ${partition.part-type} ${diskoLib.maybeStr partition.fs-type} ${diskoLib.maybeStr partition.fs-type} ${partition.start} ${partition.end}
           ''}
           # ensure /dev/disk/by-path/..-partN exists before continuing
-          udevadm trigger --subsystem-match=block; udevadm settle
+          udevadm trigger --subsystem-match=block
+          udevadm settle
           ${lib.optionalString partition.bootable ''
             parted -s ${config.device} -- set ${toString partition._index} boot on
           ''}
@@ -99,7 +100,8 @@
             parted -s ${config.device} -- set ${toString partition._index} ${flag} on
           '') partition.flags}
           # ensure further operations can detect new partitions
-          udevadm trigger --subsystem-match=block; udevadm settle
+          udevadm trigger --subsystem-match=block
+          udevadm settle
           ${lib.optionalString (partition.content != null) partition.content._create}
         '') config.partitions)}
       '';

lib/types/zfs_volume.nix

@@ -48,8 +48,10 @@
       inherit config options;
       default = ''
         zfs create ${config._parent.name}/${config.name} \
-          ${lib.concatStringsSep " " (lib.mapAttrsToList (n: v: "-o ${n}=${v}") config.options)} -V ${config.size}
+          ${lib.concatStringsSep " " (lib.mapAttrsToList (n: v: "-o ${n}=${v}") config.options)} \
-        udevadm trigger --subsystem-match=block; udevadm settle
+          -V ${config.size}
+        udevadm trigger --subsystem-match=block
+        udevadm settle
         ${lib.optionalString (config.content != null) config.content._create}
       '';
     };

lib/types/zpool.nix

@@ -83,7 +83,7 @@
         in
         {
           dev = ''
-            zpool list '${config.name}' >/dev/null 2>/dev/null || \
+            zpool list '${config.name}' >/dev/null 2>/dev/null ||
               zpool import -l -R ${config.mountRoot} '${config.name}'
             ${lib.concatMapStrings (x: x.dev or "") (lib.attrValues datasetMounts)}
           '';