From 109e41269273382b7a6805c8d3f5666b40416f30 Mon Sep 17 00:00:00 2001
From: Kristoffer Dalby <kristoffer@tailscale.com>
Date: Sat, 10 May 2025 08:11:27 +0200
Subject: [PATCH] db: add back last_seen to the database

Fixes #2574

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>
---
 cmd/headscale/cli/utils.go |  4 ++--
 hscontrol/app.go           |  4 ++--
 hscontrol/db/db.go         | 19 ++++++++++++++++++-
 hscontrol/db/node.go       | 14 ++++++++++++++
 hscontrol/poll.go          |  4 ++++
 hscontrol/types/node.go    |  6 +-----
 6 files changed, 41 insertions(+), 10 deletions(-)

diff --git a/cmd/headscale/cli/utils.go b/cmd/headscale/cli/utils.go
index ff1137be..0347c0a9 100644
--- a/cmd/headscale/cli/utils.go
+++ b/cmd/headscale/cli/utils.go
@@ -27,14 +27,14 @@ func newHeadscaleServerWithConfig() (*hscontrol.Headscale, error) {
 	cfg, err := types.LoadServerConfig()
 	if err != nil {
 		return nil, fmt.Errorf(
-			"failed to load configuration while creating headscale instance: %w",
+			"loading configuration: %w",
 			err,
 		)
 	}
 
 	app, err := hscontrol.NewHeadscale(cfg)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("creating new headscale: %w", err)
 	}
 
 	return app, nil
diff --git a/hscontrol/app.go b/hscontrol/app.go
index 3b4be52f..d62acb34 100644
--- a/hscontrol/app.go
+++ b/hscontrol/app.go
@@ -145,7 +145,7 @@ func NewHeadscale(cfg *types.Config) (*Headscale, error) {
 		registrationCache,
 	)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("new database: %w", err)
 	}
 
 	app.ipAlloc, err = db.NewIPAllocator(app.db, cfg.PrefixV4, cfg.PrefixV6, cfg.IPAllocation)
@@ -160,7 +160,7 @@ func NewHeadscale(cfg *types.Config) (*Headscale, error) {
 	})
 
 	if err = app.loadPolicyManager(); err != nil {
-		return nil, fmt.Errorf("failed to load ACL policy: %w", err)
+		return nil, fmt.Errorf("loading ACL policy: %w", err)
 	}
 
 	var authProvider AuthProvider
diff --git a/hscontrol/db/db.go b/hscontrol/db/db.go
index d299771f..74f51ddc 100644
--- a/hscontrol/db/db.go
+++ b/hscontrol/db/db.go
@@ -672,7 +672,24 @@ AND auth_key_id NOT IN (
 			{
 				ID: "202502171819",
 				Migrate: func(tx *gorm.DB) error {
-					_ = tx.Migrator().DropColumn(&types.Node{}, "last_seen")
+					// This migration originally removed the last_seen column
+					// from the node table, but it was added back in
+					// 202505091439.
+					return nil
+				},
+				Rollback: func(db *gorm.DB) error { return nil },
+			},
+			// Add back last_seen column to node table.
+			{
+				ID: "202505091439",
+				Migrate: func(tx *gorm.DB) error {
+					// Add back last_seen column to node table if it does not exist.
+					// This is a workaround for the fact that the last_seen column
+					// was removed in the 202502171819 migration, but only for some
+					// beta testers.
+					if !tx.Migrator().HasColumn(&types.Node{}, "last_seen") {
+						_ = tx.Migrator().AddColumn(&types.Node{}, "last_seen")
+					}
 
 					return nil
 				},
diff --git a/hscontrol/db/node.go b/hscontrol/db/node.go
index ed9e1f73..c91687da 100644
--- a/hscontrol/db/node.go
+++ b/hscontrol/db/node.go
@@ -251,6 +251,20 @@ func SetApprovedRoutes(
 	return nil
 }
 
+// SetLastSeen sets a node's last seen field indicating that we
+// have recently communicating with this node.
+func (hsdb *HSDatabase) SetLastSeen(nodeID types.NodeID, lastSeen time.Time) error {
+	return hsdb.Write(func(tx *gorm.DB) error {
+		return SetLastSeen(tx, nodeID, lastSeen)
+	})
+}
+
+// SetLastSeen sets a node's last seen field indicating that we
+// have recently communicating with this node.
+func SetLastSeen(tx *gorm.DB, nodeID types.NodeID, lastSeen time.Time) error {
+	return tx.Model(&types.Node{}).Where("id = ?", nodeID).Update("last_seen", lastSeen).Error
+}
+
 // RenameNode takes a Node struct and a new GivenName for the nodes
 // and renames it. If the name is not unique, it will return an error.
 func RenameNode(tx *gorm.DB,
diff --git a/hscontrol/poll.go b/hscontrol/poll.go
index e4178f43..763ab85b 100644
--- a/hscontrol/poll.go
+++ b/hscontrol/poll.go
@@ -409,6 +409,10 @@ func (h *Headscale) updateNodeOnlineStatus(online bool, node *types.Node) {
 		change.LastSeen = &now
 	}
 
+	if node.LastSeen != nil {
+		h.db.SetLastSeen(node.ID, *node.LastSeen)
+	}
+
 	ctx := types.NotifyCtx(context.Background(), "poll-nodeupdate-onlinestatus", node.Hostname)
 	h.nodeNotifier.NotifyWithIgnore(ctx, types.UpdatePeerPatch(change), node.ID)
 }
diff --git a/hscontrol/types/node.go b/hscontrol/types/node.go
index 2749237e..da185563 100644
--- a/hscontrol/types/node.go
+++ b/hscontrol/types/node.go
@@ -98,11 +98,7 @@ type Node struct {
 
 	// LastSeen is when the node was last in contact with
 	// headscale. It is best effort and not persisted.
-	LastSeen *time.Time `gorm:"-"`
-
-	// DEPRECATED: Use the ApprovedRoutes field instead.
-	// TODO(kradalby): remove when ApprovedRoutes is used all over the code.
-	// Routes []Route `gorm:"constraint:OnDelete:CASCADE;"`
+	LastSeen *time.Time `gorm:"column:last_seen"`
 
 	// ApprovedRoutes is a list of routes that the node is allowed to announce
 	// as a subnet router. They are not necessarily the routes that the node