From 999c7ee287502e3d7be037d7bc9ccc338146140f Mon Sep 17 00:00:00 2001
From: Juan Font Alonso <juanfontalonso@gmail.com>
Date: Wed, 13 Oct 2021 00:46:19 +0200
Subject: [PATCH] Show if a authkey has been used already (fixes #154)

---
 cmd/headscale/cli/preauthkeys.go |  3 ++-
 preauth_keys.go                  | 12 ++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/cmd/headscale/cli/preauthkeys.go b/cmd/headscale/cli/preauthkeys.go
index 1340267e..28bbb7e7 100644
--- a/cmd/headscale/cli/preauthkeys.go
+++ b/cmd/headscale/cli/preauthkeys.go
@@ -57,7 +57,7 @@ var listPreAuthKeys = &cobra.Command{
 			return
 		}
 
-		d := pterm.TableData{{"ID", "Key", "Reusable", "Ephemeral", "Expiration", "Created"}}
+		d := pterm.TableData{{"ID", "Key", "Reusable", "Ephemeral", "AlreadyUsed", "Expiration", "Created"}}
 		for _, k := range *keys {
 			expiration := "-"
 			if k.Expiration != nil {
@@ -76,6 +76,7 @@ var listPreAuthKeys = &cobra.Command{
 				k.Key,
 				reusable,
 				strconv.FormatBool(k.Ephemeral),
+				fmt.Sprintf("%v", k.AlreadyUsed),
 				expiration,
 				k.CreatedAt.Format("2006-01-02 15:04:05"),
 			})
diff --git a/preauth_keys.go b/preauth_keys.go
index cc849fc0..5adaee8a 100644
--- a/preauth_keys.go
+++ b/preauth_keys.go
@@ -22,6 +22,8 @@ type PreAuthKey struct {
 	Reusable    bool
 	Ephemeral   bool `gorm:"default:false"`
 
+	AlreadyUsed bool `gorm:"-"` // this field is not stored in the DB, has to be manually filled
+
 	CreatedAt  *time.Time
 	Expiration *time.Time
 }
@@ -64,6 +66,16 @@ func (h *Headscale) GetPreAuthKeys(namespaceName string) (*[]PreAuthKey, error)
 	if err := h.db.Preload("Namespace").Where(&PreAuthKey{NamespaceID: n.ID}).Find(&keys).Error; err != nil {
 		return nil, err
 	}
+
+	for i, k := range keys {
+		machines := []Machine{}
+		if err := h.db.Preload("AuthKey").Where(&Machine{AuthKeyID: uint(k.ID)}).Find(&machines).Error; err != nil {
+			return nil, err
+		}
+		if len(machines) > 0 {
+			keys[i].AlreadyUsed = true
+		}
+	}
 	return &keys, nil
 }