disk: move createFilesystem to disk.go

Move the `createFilesystem` method over the `disk.go` and make it
a public method of `PartitionTable`.

internal/disk/customizations.go

@@ -1,11 +1,8 @@
 package disk
 
 import (
-	"encoding/hex"
-	"io"
 	"math/rand"
 
-	"github.com/google/uuid"
 	"github.com/osbuild/osbuild-composer/internal/blueprint"
 )
 
@@ -38,7 +35,7 @@ func CreatePartitionTable(
 	for _, m := range mountpoints {
 		sectors := table.BytesToSectors(m.MinSize)
 		if m.Mountpoint != "/" {
-			table.createFilesystem(m.Mountpoint, sectors)
+			table.CreateFilesystem(m.Mountpoint, sectors)
 		}
 	}
 
@@ -62,43 +59,3 @@ func CreatePartitionTable(
 
 	return *table, nil
 }
-
-func (pt *PartitionTable) createFilesystem(mountpoint string, size uint64) {
-	filesystem := Filesystem{
-		Type:         "xfs",
-		Mountpoint:   mountpoint,
-		FSTabOptions: "defaults",
-		FSTabFreq:    0,
-		FSTabPassNo:  0,
-	}
-
-	partition := Partition{
-		Size:       size,
-		Filesystem: &filesystem,
-	}
-
-	if pt.Type == "gpt" {
-		partition.Type = FilesystemDataGUID
-	}
-
-	pt.Partitions = append(pt.Partitions, partition)
-}
-
-func newRandomUUIDFromReader(r io.Reader) (uuid.UUID, error) {
-	var id uuid.UUID
-	_, err := io.ReadFull(r, id[:])
-	if err != nil {
-		return uuid.Nil, err
-	}
-	id[6] = (id[6] & 0x0f) | 0x40 // Version 4
-	id[8] = (id[8] & 0x3f) | 0x80 // Variant is 10
-	return id, nil
-}
-
-// NewRandomVolIDFromReader creates a random 32 bit hex string to use as a
-// volume ID for FAT filesystems
-func NewRandomVolIDFromReader(r io.Reader) (string, error) {
-	volid := make([]byte, 4)
-	_, err := r.Read(volid)
-	return hex.EncodeToString(volid), err
-}

internal/disk/disk.go

@@ -5,7 +5,9 @@
 package disk
 
 import (
+	"encoding/hex"
 	"errors"
+	"io"
 	"math/rand"
 	"sort"
 
@@ -269,6 +271,29 @@ func (pt *PartitionTable) BootFilesystem() *Filesystem {
 	return pt.FindFilesystemForMountpoint("/boot")
 }
 
+// Create a new filesystem within the partition table at the given mountpoint
+// with the given minimum size in sectors.
+func (pt *PartitionTable) CreateFilesystem(mountpoint string, size uint64) {
+	filesystem := Filesystem{
+		Type:         "xfs",
+		Mountpoint:   mountpoint,
+		FSTabOptions: "defaults",
+		FSTabFreq:    0,
+		FSTabPassNo:  0,
+	}
+
+	partition := Partition{
+		Size:       size,
+		Filesystem: &filesystem,
+	}
+
+	if pt.Type == "gpt" {
+		partition.Type = FilesystemDataGUID
+	}
+
+	pt.Partitions = append(pt.Partitions, partition)
+}
+
 // Generate all needed UUIDs for all the partiton and filesystems
 //
 // Will not overwrite existing UUIDs and only generate UUIDs for
@@ -365,3 +390,26 @@ func (fs *Filesystem) QEMUFilesystem() osbuild.QEMUFilesystem {
 		Mountpoint: fs.Mountpoint,
 	}
 }
+
+// uuid generator helpers
+
+// GeneratesnewRandomUUIDFromReader generates a new random UUID (version
+// 4 using) via the given random number generator.
+func newRandomUUIDFromReader(r io.Reader) (uuid.UUID, error) {
+	var id uuid.UUID
+	_, err := io.ReadFull(r, id[:])
+	if err != nil {
+		return uuid.Nil, err
+	}
+	id[6] = (id[6] & 0x0f) | 0x40 // Version 4
+	id[8] = (id[8] & 0x3f) | 0x80 // Variant is 10
+	return id, nil
+}
+
+// NewRandomVolIDFromReader creates a random 32 bit hex string to use as a
+// volume ID for FAT filesystems
+func NewRandomVolIDFromReader(r io.Reader) (string, error) {
+	volid := make([]byte, 4)
+	_, err := r.Read(volid)
+	return hex.EncodeToString(volid), err
+}