denormalise PreAuthKey tags

this commit denormalises the Tags related to a Pre auth key
back onto the preauthkey table and struct as a string list.

There was not really any real normalisation here as we just added
a bunch of duplicate tags with new IDs and preauthkeyIDs, lots of
GORM cermony but no actual advantage.

This work is the start to fixup tags which currently are not working
as they should.

Updates juanfont#1369

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

hscontrol/db/db.go

@@ -3,6 +3,7 @@ package db
 import (
 	"context"
 	"database/sql"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"net/netip"
@@ -19,6 +20,7 @@ import (
 	"gorm.io/driver/postgres"
 	"gorm.io/gorm"
 	"gorm.io/gorm/logger"
+	"tailscale.com/util/set"
 )
 
 var errDatabaseNotSupported = errors.New("database type not supported")
@@ -291,7 +293,12 @@ func NewHeadscaleDatabase(
 						return err
 					}
 
-					err = tx.AutoMigrate(&types.PreAuthKeyACLTag{})
+					type preAuthKeyACLTag struct {
+						ID           uint64 `gorm:"primary_key"`
+						PreAuthKeyID uint64
+						Tag          string
+					}
+					err = tx.AutoMigrate(&preAuthKeyACLTag{})
 					if err != nil {
 						return err
 					}
@@ -413,6 +420,54 @@ func NewHeadscaleDatabase(
 				},
 				Rollback: func(db *gorm.DB) error { return nil },
 			},
+			// denormalise the ACL tags for preauth keys back onto
+			// the preauth key table. We dont normalise or reuse and
+			// it is just a bunch of work for extra work.
+			{
+				ID: "202409271400",
+				Migrate: func(tx *gorm.DB) error {
+					preauthkeyTags := map[uint64]set.Set[string]{}
+
+					type preAuthKeyACLTag struct {
+						ID           uint64 `gorm:"primary_key"`
+						PreAuthKeyID uint64
+						Tag          string
+					}
+
+					var aclTags []preAuthKeyACLTag
+					if err := tx.Find(&aclTags).Error; err != nil {
+						return err
+					}
+
+					// Store the current tags.
+					for _, tag := range aclTags {
+						if preauthkeyTags[tag.PreAuthKeyID] == nil {
+							preauthkeyTags[tag.PreAuthKeyID] = set.SetOf([]string{tag.Tag})
+						} else {
+							preauthkeyTags[tag.PreAuthKeyID].Add(tag.Tag)
+						}
+					}
+
+					// Add tags column and restore the tags.
+					_ = tx.Migrator().AddColumn(&types.PreAuthKey{}, "tags")
+					for keyID, tags := range preauthkeyTags {
+						s := tags.Slice()
+						j, err := json.Marshal(s)
+						if err != nil {
+							return err
+						}
+						if err := tx.Model(&types.PreAuthKey{}).Where("id = ?", keyID).Update("tags", string(j)).Error; err != nil {
+							return err
+						}
+					}
+
+					// Drop the old table.
+					_ = tx.Migrator().DropTable(&preAuthKeyACLTag{})
+
+					return nil
+				},
+				Rollback: func(db *gorm.DB) error { return nil },
+			},
 		},
 	)
 

hscontrol/db/db_test.go

@@ -6,6 +6,8 @@ import (
 	"net/netip"
 	"os"
 	"path/filepath"
+	"slices"
+	"sort"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -108,6 +110,68 @@ func TestMigrations(t *testing.T) {
 				}
 			},
 		},
+		// at 14:15:06 ❯ go run ./cmd/headscale preauthkeys list
+		// ID | Key      | Reusable | Ephemeral | Used  | Expiration | Created    | Tags
+		// 1  | 09b28f.. | false    | false     | false | 2024-09-27 | 2024-09-27 | tag:derp
+		// 2  | 3112b9.. | false    | false     | false | 2024-09-27 | 2024-09-27 | tag:derp
+		// 3  | 7c23b9.. | false    | false     | false | 2024-09-27 | 2024-09-27 | tag:derp,tag:merp
+		// 4  | f20155.. | false    | false     | false | 2024-09-27 | 2024-09-27 | tag:test
+		// 5  | b212b9.. | false    | false     | false | 2024-09-27 | 2024-09-27 | tag:test,tag:woop,tag:dedu
+		{
+			dbPath: "testdata/0-23-0-to-0-24-0-preauthkey-tags-table.sqlite",
+			wantFunc: func(t *testing.T, h *HSDatabase) {
+				keys, err := Read(h.DB, func(rx *gorm.DB) ([]types.PreAuthKey, error) {
+					kratest, err := ListPreAuthKeys(rx, "kratest")
+					if err != nil {
+						return nil, err
+					}
+
+					testkra, err := ListPreAuthKeys(rx, "testkra")
+					if err != nil {
+						return nil, err
+					}
+
+					return append(kratest, testkra...), nil
+				})
+				assert.NoError(t, err)
+
+				assert.Len(t, keys, 5)
+				want := []types.PreAuthKey{
+					{
+						ID:   1,
+						Tags: []string{"tag:derp"},
+					},
+					{
+						ID:   2,
+						Tags: []string{"tag:derp"},
+					},
+					{
+						ID:   3,
+						Tags: []string{"tag:derp", "tag:merp"},
+					},
+					{
+						ID:   4,
+						Tags: []string{"tag:test"},
+					},
+					{
+						ID:   5,
+						Tags: []string{"tag:test", "tag:woop", "tag:dedu"},
+					},
+				}
+
+				if diff := cmp.Diff(want, keys, cmp.Comparer(func(a, b []string) bool {
+					sort.Sort(sort.StringSlice(a))
+					sort.Sort(sort.StringSlice(b))
+					return slices.Equal(a, b)
+				}), cmpopts.IgnoreFields(types.PreAuthKey{}, "Key", "UserID", "User", "CreatedAt", "Expiration")); diff != "" {
+					t.Errorf("TestMigrations() mismatch (-want +got):\n%s", diff)
+				}
+
+				if h.DB.Migrator().HasTable("pre_auth_key_acl_tags") {
+					t.Errorf("TestMigrations() table pre_auth_key_acl_tags should not exist")
+				}
+			},
+		},
 	}
 
 	for _, tt := range tests {

hscontrol/db/preauth_keys.go

@@ -71,28 +71,13 @@ func CreatePreAuthKey(
 		Ephemeral:  ephemeral,
 		CreatedAt:  &now,
 		Expiration: expiration,
+		Tags:       types.StringList(aclTags),
 	}
 
 	if err := tx.Save(&key).Error; err != nil {
 		return nil, fmt.Errorf("failed to create key in the database: %w", err)
 	}
 
-	if len(aclTags) > 0 {
-		seenTags := map[string]bool{}
-
-		for _, tag := range aclTags {
-			if !seenTags[tag] {
-				if err := tx.Save(&types.PreAuthKeyACLTag{PreAuthKeyID: key.ID, Tag: tag}).Error; err != nil {
-					return nil, fmt.Errorf(
-						"failed to create key tag in the database: %w",
-						err,
-					)
-				}
-				seenTags[tag] = true
-			}
-		}
-	}
-
 	return &key, nil
 }
 
@@ -110,7 +95,7 @@ func ListPreAuthKeys(tx *gorm.DB, userName string) ([]types.PreAuthKey, error) {
 	}
 
 	keys := []types.PreAuthKey{}
-	if err := tx.Preload("User").Preload("ACLTags").Where(&types.PreAuthKey{UserID: user.ID}).Find(&keys).Error; err != nil {
+	if err := tx.Preload("User").Where(&types.PreAuthKey{UserID: user.ID}).Find(&keys).Error; err != nil {
 		return nil, err
 	}
 
@@ -135,10 +120,6 @@ func GetPreAuthKey(tx *gorm.DB, user string, key string) (*types.PreAuthKey, err
 // does not exist.
 func DestroyPreAuthKey(tx *gorm.DB, pak types.PreAuthKey) error {
 	return tx.Transaction(func(db *gorm.DB) error {
-		if result := db.Unscoped().Where(types.PreAuthKeyACLTag{PreAuthKeyID: pak.ID}).Delete(&types.PreAuthKeyACLTag{}); result.Error != nil {
-			return result.Error
-		}
-
 		if result := db.Unscoped().Delete(pak); result.Error != nil {
 			return result.Error
 		}
@@ -182,7 +163,7 @@ func (hsdb *HSDatabase) ValidatePreAuthKey(k string) (*types.PreAuthKey, error)
 // If returns no error and a PreAuthKey, it can be used.
 func ValidatePreAuthKey(tx *gorm.DB, k string) (*types.PreAuthKey, error) {
 	pak := types.PreAuthKey{}
-	if result := tx.Preload("User").Preload("ACLTags").First(&pak, "key = ?", k); errors.Is(
+	if result := tx.Preload("User").First(&pak, "key = ?", k); errors.Is(
 		result.Error,
 		gorm.ErrRecordNotFound,
 	) {

hscontrol/types/preauth_key.go

@@ -16,21 +16,14 @@ type PreAuthKey struct {
 	UserID    uint
 	User      User `gorm:"constraint:OnDelete:CASCADE;"`
 	Reusable  bool
-	Ephemeral bool               `gorm:"default:false"`
-	Used      bool               `gorm:"default:false"`
-	ACLTags   []PreAuthKeyACLTag `gorm:"constraint:OnDelete:CASCADE;"`
+	Ephemeral bool     `gorm:"default:false"`
+	Used      bool     `gorm:"default:false"`
+	Tags      []string `gorm:"serializer:json"`
 
 	CreatedAt  *time.Time
 	Expiration *time.Time
 }
 
-// PreAuthKeyACLTag describes an autmatic tag applied to a node when registered with the associated PreAuthKey.
-type PreAuthKeyACLTag struct {
-	ID           uint64 `gorm:"primary_key"`
-	PreAuthKeyID uint64
-	Tag          string
-}
-
 func (key *PreAuthKey) Proto() *v1.PreAuthKey {
 	protoKey := v1.PreAuthKey{
 		User:      key.User.Name,
@@ -39,7 +32,7 @@ func (key *PreAuthKey) Proto() *v1.PreAuthKey {
 		Ephemeral: key.Ephemeral,
 		Reusable:  key.Reusable,
 		Used:      key.Used,
-		AclTags:   make([]string, len(key.ACLTags)),
+		AclTags:   key.Tags,
 	}
 
 	if key.Expiration != nil {
@@ -50,9 +43,5 @@ func (key *PreAuthKey) Proto() *v1.PreAuthKey {
 		protoKey.CreatedAt = timestamppb.New(*key.CreatedAt)
 	}
 
-	for idx := range key.ACLTags {
-		protoKey.AclTags[idx] = key.ACLTags[idx].Tag
-	}
-
 	return &protoKey
 }