core: Windows service integration (#4790)

Co-authored-by: Matthew Holt <mholt@users.noreply.github.com>

3 files changed, 55 insertions, 13 deletions

diff --git a/notify/notify_linux.go b/notify/notify_linux.go
index 8ba49d2..1e8da74 100644
--- a/notify/notify_linux.go
+++ b/notify/notify_linux.go
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package notify provides facilities for notifying process managers
+// of state changes, mainly for when running as a system service.
 package notify
 
 import (
diff --git a/notify/notify_other.go b/notify/notify_other.go
index 6ffec89..7fc618b 100644
--- a/notify/notify_other.go
+++ b/notify/notify_other.go
@@ -12,19 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build !linux
-// +build !linux
+//go:build !linux && !windows
 
 package notify
 
-func notifyReadiness() error {
-	return nil
-}
-
-func notifyReloading() error {
-	return nil
-}
-
-func notifyStopping() error {
-	return nil
-}
+func notifyReadiness() error { return nil }
+func notifyReloading() error { return nil }
+func notifyStopping() error  { return nil }
diff --git a/notify/notify_windows.go b/notify/notify_windows.go
new file mode 100644
index 0000000..a551fc7
--- /dev/null
+++ b/notify/notify_windows.go
@@ -0,0 +1,49 @@
+// Copyright 2015 Matthew Holt and The Caddy Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package notify
+
+import "golang.org/x/sys/windows/svc"
+
+// globalStatus store windows service status, it can be
+// use to notify caddy status.
+var globalStatus chan<- svc.Status
+
+func SetGlobalStatus(status chan<- svc.Status) {
+	globalStatus = status
+}
+
+func notifyReadiness() error {
+	if globalStatus != nil {
+		globalStatus <- svc.Status{
+			State:   svc.Running,
+			Accepts: svc.AcceptStop | svc.AcceptShutdown,
+		}
+	}
+	return nil
+}
+
+func notifyReloading() error {
+	if globalStatus != nil {
+		globalStatus <- svc.Status{State: svc.StartPending}
+	}
+	return nil
+}
+
+func notifyStopping() error {
+	if globalStatus != nil {
+		globalStatus <- svc.Status{State: svc.StopPending}
+	}
+	return nil
+}