Reconnect at once when the Mac wakes or its network changes

mac/Sources/Byre/EventStream.swift

@@ -1,5 +1,4 @@
 import Foundation
-import Network
 import SwiftUI
 
 private let staleAfter: TimeInterval = 40
@@ -26,8 +25,7 @@ final class EventStream {
     private var retry: Task<Void, Never>?
     private var checker: Task<Void, Never>?
     private var generation = 0
-    private let monitor = NWPathMonitor()
-    private var online: Bool?
+    private var networkObserver: (any NSObjectProtocol)?
     private var activeObserver: NotificationCenter.ObservationToken?
 
     init(api: API, after: Int64, lead: Bool, onEvent: @escaping (ByreEvent) -> Void, onState: @escaping (Bool) -> Void, onReady: @escaping () -> Void) {
@@ -43,13 +41,9 @@ final class EventStream {
                 self?.check()
             }
         }
-        monitor.pathUpdateHandler = { [weak self] path in
-            let up = path.status == .satisfied
-            Task { @MainActor in
-                self?.pathChanged(up)
-            }
+        networkObserver = NetworkWatch.shared.observe { [weak self] in
+            self?.connect()
         }
-        monitor.start(queue: .main)
         #if os(macOS)
         activeObserver = NotificationCenter.default.addObserver(of: NSApplication.self, for: .didBecomeActive) { [weak self] _ in
             self?.check()
@@ -67,21 +61,16 @@ final class EventStream {
         checker?.cancel()
         retry?.cancel()
         reading?.cancel()
-        monitor.cancel()
+        if let networkObserver {
+            NotificationCenter.default.removeObserver(networkObserver)
+        }
+        networkObserver = nil
         if let activeObserver {
             NotificationCenter.default.removeObserver(activeObserver)
         }
         activeObserver = nil
     }
 
-    private func pathChanged(_ up: Bool) {
-        let was = online
-        online = up
-        if was == false && up {
-            connect()
-        }
-    }
-
     private func check() {
         if Date().timeIntervalSince(heard) < staleAfter {
             return

mac/Sources/Byre/NetworkWatch.swift

@@ -0,0 +1,54 @@
+import Foundation
+import Network
+#if os(macOS)
+import AppKit
+#endif
+
+private let networkChanged = Notification.Name("run.fc.byre.networkChanged")
+
+@MainActor
+final class NetworkWatch {
+    static let shared = NetworkWatch()
+
+    private let monitor = NWPathMonitor()
+    private var seen = false
+
+    private init() {
+        monitor.pathUpdateHandler = { [weak self] path in
+            let summary = "\(path.status) \(path.availableInterfaces.map(\.name).joined(separator: " "))"
+            Task { @MainActor in
+                self?.pathChanged(summary)
+            }
+        }
+        monitor.start(queue: .main)
+        #if os(macOS)
+        NSWorkspace.shared.notificationCenter.addObserver(forName: NSWorkspace.didWakeNotification, object: nil, queue: .main) { [weak self] _ in
+            Task { @MainActor in
+                log.notice("woke from sleep, reconnecting")
+                self?.post()
+            }
+        }
+        #endif
+    }
+
+    func observe(_ handler: @escaping @MainActor () -> Void) -> any NSObjectProtocol {
+        NotificationCenter.default.addObserver(forName: networkChanged, object: self, queue: .main) { _ in
+            MainActor.assumeIsolated {
+                handler()
+            }
+        }
+    }
+
+    private func pathChanged(_ summary: String) {
+        guard seen else {
+            seen = true
+            return
+        }
+        log.notice("network changed (\(summary, privacy: .public)), reconnecting")
+        post()
+    }
+
+    private func post() {
+        NotificationCenter.default.post(name: networkChanged, object: self)
+    }
+}

mac/Sources/Byre/Remote.swift

@@ -38,6 +38,7 @@ final class Remote {
     private var stopped = false
     private var heard = Date()
     private var checker: Task<Void, Never>?
+    private var networkObserver: (any NSObjectProtocol)?
 
     init(api: API) {
         self.api = api
@@ -69,16 +70,30 @@ final class Remote {
                     self?.check()
                 }
             }
+            networkObserver = NetworkWatch.shared.observe { [weak self] in
+                self?.restart()
+            }
         }
     }
 
     func stop() {
         stopped = true
         checker?.cancel()
+        if let networkObserver {
+            NotificationCenter.default.removeObserver(networkObserver)
+        }
+        networkObserver = nil
         ws?.cancel(with: .normalClosure, reason: nil)
         ws = nil
     }
 
+    private func restart() {
+        let old = ws
+        ws = nil
+        old?.cancel(with: .goingAway, reason: nil)
+        start()
+    }
+
     // A socket byre closed while this Mac slept stays open here until something is sent on it.
     private func check() {
         guard let task = ws else {
@@ -122,7 +137,9 @@ final class Remote {
                     log.notice("client connection closed:\(errorText(error), privacy: .public)")
                     self.ws = nil
                     try? await Task.sleep(for: retryAfter)
-                    self.start()
+                    if self.ws == nil {
+                        self.start()
+                    }
                 }
             }
         }