Fix 764 (#2093)

* Fix KeyExpiration when a zero time value has a timezone

When a zero time value is loaded from JSON or a DB in a way that
assigns it the local timezone, it does not roudtrip in JSON as a
value for which IsZero returns true. This causes KeyExpiry to be
treated as a far past value instead of a nilish value.

See https://github.com/golang/go/issues/57040

* Fix whitespace

* Ensure that postgresql is used for all tests when env var is set

* Pass through value of HEADSCALE_INTEGRATION_POSTGRES env var

* Add option to set timezone on headscale container

* Add test for registration with auth key in alternate timezone

hscontrol/mapper/tail.go

@@ -93,7 +93,7 @@ func tailNode(
 		User: tailcfg.UserID(node.UserID),
 
 		Key:       node.NodeKey,
-		KeyExpiry: keyExpiry,
+		KeyExpiry: keyExpiry.UTC(),
 
 		Machine:    node.MachineKey,
 		DiscoKey:   node.DiscoKey,
@@ -102,7 +102,7 @@ func tailNode(
 		Endpoints:  node.Endpoints,
 		DERP:       derp,
 		Hostinfo:   node.Hostinfo.View(),
-		Created:    node.CreatedAt,
+		Created:    node.CreatedAt.UTC(),
 
 		Online: node.IsOnline,
 

hscontrol/mapper/tail_test.go

@@ -1,6 +1,7 @@
 package mapper
 
 import (
+	"encoding/json"
 	"net/netip"
 	"testing"
 	"time"
@@ -205,3 +206,68 @@ func TestTailNode(t *testing.T) {
 		})
 	}
 }
+
+func TestNodeExpiry(t *testing.T) {
+	tp := func(t time.Time) *time.Time {
+		return &t
+	}
+	tests := []struct {
+		name         string
+		exp          *time.Time
+		wantTime     time.Time
+		wantTimeZero bool
+	}{
+		{
+			name:         "no-expiry",
+			exp:          nil,
+			wantTimeZero: true,
+		},
+		{
+			name:         "zero-expiry",
+			exp:          &time.Time{},
+			wantTimeZero: true,
+		},
+		{
+			name:         "localtime",
+			exp:          tp(time.Time{}.Local()),
+			wantTimeZero: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			node := &types.Node{
+				GivenName: "test",
+				Expiry:    tt.exp,
+			}
+			tn, err := tailNode(
+				node,
+				0,
+				&policy.ACLPolicy{},
+				&types.Config{},
+			)
+			if err != nil {
+				t.Fatalf("nodeExpiry() error = %v", err)
+			}
+
+			// Round trip the node through JSON to ensure the time is serialized correctly
+			seri, err := json.Marshal(tn)
+			if err != nil {
+				t.Fatalf("nodeExpiry() error = %v", err)
+			}
+			var deseri tailcfg.Node
+			err = json.Unmarshal(seri, &deseri)
+			if err != nil {
+				t.Fatalf("nodeExpiry() error = %v", err)
+			}
+
+			if tt.wantTimeZero {
+				if !deseri.KeyExpiry.IsZero() {
+					t.Errorf("nodeExpiry() = %v, want zero", deseri.KeyExpiry)
+				}
+			} else if deseri.KeyExpiry != tt.wantTime {
+				t.Errorf("nodeExpiry() = %v, want %v", deseri.KeyExpiry, tt.wantTime)
+			}
+		})
+	}
+}