Merge pull request #2 from orobio/get-watchdog-configuration-from-sys…

…temd

Get watchdog configuration from systemd

Sources/Systemd/SystemdHelpers.swift

@@ -1,12 +1,17 @@
 
 #if os(Linux)
 import Glibc
+import CSystemd
 #endif
 
 import Foundation
 
 public struct SystemdHelpers {
     public static let isSystemdService: Bool = getIsSystemdService()
+    public static let watchdogTimeout: Duration? = getWatchdogTimeout()
+
+    public static var watchdogEnabled: Bool { watchdogTimeout != nil }
+    public static var watchdogRecommendedNotifyInterval: Duration? { watchdogTimeout.map { $0 / 2 } }
 
     private static func getIsSystemdService() -> Bool {
         #if os(Linux)
@@ -22,4 +27,22 @@ public struct SystemdHelpers {
 
         return false
     }
+
+    private static func getWatchdogTimeout() -> Duration? {
+        #if os(Linux)
+        var usec: UInt64 = 0
+        let ret = sd_watchdog_enabled(0, &usec)
+        if ret > 0 {
+            return .microseconds(usec)
+        } else if ret == 0 {
+            return nil // Watchdog disabled
+        } else {
+            let error = String(cString: strerror(-ret))
+            print("Unable to get watchdog configuration: \(error)")
+            return nil
+        }
+        #else
+        return nil
+        #endif
+   }
 }

Sources/SystemdLifecycle/SystemdService.swift

@@ -4,24 +4,20 @@ import ServiceLifecycle
 import Systemd
 
 public struct SystemdService: Service {
-    private let _watchdogEnabled: Bool
-    private let _watchdogInterval: Duration
-
-    public init(watchdogEnabled: Bool = false,
-                watchdogInterval: Duration = .seconds(5)) {
-        _watchdogEnabled = watchdogEnabled
-        _watchdogInterval = watchdogInterval
-    }
+    public init() {}
 
     public func run() async throws {
         let notifier = SystemdNotifier()
 
         // Send ready signal at startup
         notifier.notify(ServiceState.Ready)
 
+
         // Run the task until cancelled
-        for await _ in AsyncTimerSequence(interval: _watchdogInterval, clock: .continuous).cancelOnGracefulShutdown() {
-            if _watchdogEnabled {
+        let watchdogEnabled = SystemdHelpers.watchdogEnabled
+        let interval = SystemdHelpers.watchdogRecommendedNotifyInterval ?? .seconds(3600)
+        for await _ in AsyncTimerSequence(interval: interval, clock: .continuous).cancelOnGracefulShutdown() {
+            if watchdogEnabled {
                 notifier.notify(ServiceState.Watchdog)
             }
         }