Restarting WWDCAgent when a new version is detected (i.e. after app u…

…pdates)

WWDC/AppDelegate.swift

@@ -21,6 +21,8 @@ extension Notification.Name {
 
 class AppDelegate: NSObject, NSApplicationDelegate {
 
+    private lazy var agentController = WWDCAgentController()
+
     private let log = OSLog(subsystem: "io.wwdc.app", category: String(describing: AppDelegate.self))
 
     private lazy var commandsReceiver = AppCommandsReceiver()
@@ -62,6 +64,8 @@ class AppDelegate: NSObject, NSApplicationDelegate {
 
     func applicationDidFinishLaunching(_ notification: Notification) {
         UserDefaults.standard.register(defaults: ["NSApplicationCrashOnExceptions": false])
+
+        agentController.registerAgentVersion()
 
         NSApp.registerForRemoteNotifications(matching: [])
 

WWDC/WWDCAgentController.swift

@@ -8,13 +8,16 @@
 
 import Cocoa
 import ServiceManagement
+import os.log
 
 extension Notification.Name {
     static let WWDCAgentEnabledPreferenceChanged = Notification.Name("io.wwdc.app.AgentEnabledPreferenceChanged")
 }
 
 final class WWDCAgentController: NSObject {
 
+    private let log = OSLog(subsystem: "io.wwdc.app", category: String(describing: WWDCAgentController.self))
+
     static private(set) var isAgentEnabled: Bool {
         get { UserDefaults.standard.bool(forKey: #function) }
         set {
@@ -31,7 +34,12 @@ final class WWDCAgentController: NSObject {
         }
     }
 
-    private lazy var agentBundleIdentifier: String = {
+    private(set) var lastRunAgentBuild: String? {
+        get { UserDefaults.standard.string(forKey: #function) }
+        set { UserDefaults.standard.set(newValue, forKey: #function) }
+    }
+
+    private lazy var agentBundle: Bundle = {
         let agentURL = Bundle.main.bundleURL
             .appendingPathComponent("Contents/Library/LoginItems", isDirectory: true)
             .appendingPathComponent("WWDCAgent.app")
@@ -40,13 +48,25 @@ final class WWDCAgentController: NSObject {
             preconditionFailure("Couldn't instatiate agent bundle")
         }
 
-        guard let identifier = bundle.bundleIdentifier else {
+        return bundle
+    }()
+
+    private lazy var agentBundleIdentifier: String = {
+        guard let identifier = agentBundle.bundleIdentifier else {
             preconditionFailure("Failed to read identifier for agent bundle")
         }
 
         return identifier
     }()
 
+    private lazy var currentAgentBundleBuild: String = {
+        guard let build = agentBundle.infoDictionary?["CFBundleVersion"] as? String else {
+            preconditionFailure("Failed to read CFBundleVersion for agent bundle")
+        }
+
+        return build
+    }()
+
     func enableAgent() -> Bool {
         Self.isAgentEnabled = SMLoginItemSetEnabled(agentBundleIdentifier as CFString, true)
 
@@ -58,5 +78,31 @@ final class WWDCAgentController: NSObject {
 
         Self.isAgentEnabled = false
     }
+
+    func registerAgentVersion() {
+        guard currentAgentBundleBuild != lastRunAgentBuild else {
+            os_log("Agent bundle build has not changed", log: self.log, type: .debug)
+            return
+        }
+
+        if let build = lastRunAgentBuild {
+            os_log("Registering new agent build: %{public}@", log: self.log, type: .debug, build)
+        } else {
+            os_log("Registering agent build for the first time: %{public}@", log: self.log, type: .debug, currentAgentBundleBuild)
+        }
+
+        lastRunAgentBuild = currentAgentBundleBuild
+
+        guard let agentApp = NSRunningApplication.runningApplications(withBundleIdentifier: agentBundleIdentifier).first else {
+            os_log("Couldn't find agent app running, ignoring", log: self.log, type: .debug)
+            return
+        }
+
+        os_log("Found old agent running with pid %{public}d, restarting", log: self.log, type: .debug, agentApp.processIdentifier)
+
+        if !agentApp.forceTerminate() {
+            os_log("Failed to terminate agent", log: self.log, type: .fault)
+        }
+    }
 
 }