disko2: Add rudimenatary "generate" mode

disko2

@@ -1,8 +1,8 @@
 #!/usr/bin/env nu
 
-use lib [eval-disko-file eval-flake exit-on-error print-info print-help]
+use lib [eval-disko-file eval-flake exit-on-error print-info print-help generate-config]
 
-def modes [] { ["destroy", "format", "mount", "format,mount", "destroy,format,mount"] }
+def modes [] { ["destroy", "format", "mount", "format,mount", "destroy,format,mount", "generate"] }
 
 def with-context [context: string] {
     $in | insert context $context
@@ -24,6 +24,18 @@ export def run [
         } 
     }
 
+
+    match $args.mode {
+        "generate" => (mode-generate $args)
+        _ => (mode-format $args)
+    }
+}
+
+export def mode-generate [args: record] {
+    generate-config | with-context "generate config"
+}
+
+export def mode-format [args: record] {
     if not ($args.flake? != null xor $args.disko_file? != null) {
         return {
             success: false,
@@ -49,7 +61,7 @@ export def run [
 }
 
 export def main [
-    mode: string@modes, # Mode to use. Allowed values are 'destroy', 'format', 'mount', 'format,mount', 'destroy,format,mount'
+    mode: string@modes, # Mode to use. Allowed values are 'destroy', 'format', 'mount', 'format,mount', 'destroy,format,mount', 'generate'
     disko_file?: path, # File to read the disko configuration from. Can be a .nix file or a .json file
     --flake (-f): string # Flake URI to search for the disko configuration
     ]: nothing -> nothing {

lib/mod.nu

@@ -1,2 +1,3 @@
 export use eval-config.nu [eval-disko-file eval-flake]
 export use errors.nu [exit-on-error print-info print-help]
+export use types [generate-config]

lib/types/filesystem.nu

@@ -0,0 +1,10 @@
+
+export def generate-config [partition: record] {
+    assert ($partition.type == 'part') $'BUG! filesystem generate-config called with non-partition: ($partition)'
+
+    {
+        type: 'filesystem',
+        format: $partition.fstype,
+        mountpoint: $partition.mountpoint,
+    }
+}

lib/types/gpt.nu

@@ -0,0 +1,65 @@
+use std assert
+use std log
+
+use filesystem.nu
+
+def add-type-if-required [partition: record]: record -> record {
+    let config = $in
+
+    let type = match ($partition.parttype) {
+        'c12a7328-f81f-11d2-ba4b-00a0c93ec93b' => 'EF00' # EFI System
+        '21686148-6449-6e6f-744e-656564454649' => 'EF02' # BIOS boot
+        _ => null
+    }
+
+    if $type == null {
+        $config
+    } else {
+        $config | insert type $type
+    }
+}
+
+def generate-identifier [partition: record]: record -> string {
+    if not (partition.uuid | is-empty) {
+        $'UUID:($partition.uuid)...'
+    } else {
+        $'PARTUUID:($partition.partuuid)'
+    }
+}
+
+def generate-content [partition: record]: record -> record {
+    match ($partition.fstype) {
+        # Add filesystems that are more complicated than mkfs
+        _ => (filesystem generate-config $partition)
+    }
+}
+
+export def generate-config [device: record]: nothing -> record {
+    assert ($device.pttype == 'gpt') $'BUG! gpt generate-config called with non-gpt device: ($device)'
+
+    log debug $'Generating config for GPT device ($device.path)'
+
+    let partitions = $device.children
+    | each { |part|
+        {
+            ($'UUID:($part.uuid)'): (
+                { 
+                    size: $part.size,
+                    content: (generate-content $part)
+                }
+                | add-type-if-required $part
+            )
+        }
+    }
+    | into record
+
+    {
+        type: 'gpt',
+        partitions: $partitions
+    }
+}
+
+
+export def print-disks []: record -> nothing {
+    $in | each { print }
+}

lib/types/mod.nu

@@ -0,0 +1,74 @@
+export use gpt.nu
+
+# To see what other fields are available in the lsblk output and what
+# sort of values you can expect from them, run:
+# lsblk -O | less -S
+const lsblk_output_fields = [
+    ID-LINK,
+    FSTYPE,
+    FSSIZE,
+    FSUSE%,
+    KNAME,
+    LABEL,
+    MODEL,
+    PARTFLAGS,
+    PARTLABEL,
+    PARTN,
+    PARTTYPE,
+    PARTTYPENAME,
+    PARTUUID, # The UUID used for /dev/disk/by-partuuid
+    PATH,
+    PHY-SEC,
+    PTTYPE,
+    REV,
+    SERIAL,
+    SIZE,
+    START,
+    MOUNTPOINT, # Canonical mountpoint
+    MOUNTPOINTS, # All mountpoints, including e.g. bind mounts
+    TYPE,
+    UUID, # The UUID used for /dev/disk/by-uuid, if available
+]
+
+export def list-block-devices []: nothing -> table {
+    ^lsblk --output ($lsblk_output_fields | str join ',') --json --tree
+    | from json
+    | $in.blockdevices
+}
+
+def generate-content [device: record] nothing -> record {
+    match $device.pttype {
+        gpt => (gpt generate-config $device)
+        _ => { errors: [ { code: ERR_UNSUPPORTED_PARTITION_TABLE_TYPE, details: { pttype: $device.pttype } } ] }
+    }
+
+}
+
+export def generate-config [block_devices?: table]: nothing -> record {
+    let block_devices = $block_devices | default (list-block-devices)
+
+    let disks = $block_devices
+    | each { |device|
+        {
+            ($'MODEL:($device.model),SN:($device.serial)'):{
+                device: $device.kname,
+                type: $device.type,
+                content: (generate-content $device)
+            }
+        }
+    }
+    | into record
+
+    return {
+        success: true,
+        value: {
+            disk: $disks 
+            # TODO: Add lvm_vg, mdadm, nodev and zpool
+        }
+    }
+}
+
+
+export def print-disks []: record -> nothing {
+    $in | each { print }
+}