Outage detection.

Signal/src/ViewControllers/HomeView/HomeViewController.m

@@ -78,6 +78,7 @@ NSString *const kArchivedConversationsReuseIdentifier = @"kArchivedConversations
 @property (nonatomic) NSLayoutConstraint *hideDeregisteredViewConstraint;
 @property (nonatomic) NSLayoutConstraint *hideArchiveReminderViewConstraint;
 @property (nonatomic) NSLayoutConstraint *hideMissingContactsPermissionViewConstraint;
+@property (nonatomic) NSLayoutConstraint *outageViewConstraint;
 
 @property (nonatomic) TSThread *lastThread;
 
@@ -166,6 +167,10 @@ NSString *const kArchivedConversationsReuseIdentifier = @"kArchivedConversations
                                              selector:@selector(deregistrationStateDidChange:)
                                                  name:DeregistrationStateDidChangeNotification
                                                object:nil];
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(outageStateDidChange:)
+                                                 name:OutageDetection.outageStateDidChange
+                                               object:nil];
 }
 
 - (void)dealloc
@@ -198,6 +203,13 @@ NSString *const kArchivedConversationsReuseIdentifier = @"kArchivedConversations
     [self updateReminderViews];
 }
 
+- (void)outageStateDidChange:(id)notification
+{
+    OWSAssertIsOnMainThread();
+
+    [self updateReminderViews];
+}
+
 #pragma mark - View Life Cycle
 
 - (void)loadView
@@ -233,6 +245,13 @@ NSString *const kArchivedConversationsReuseIdentifier = @"kArchivedConversations
     self.hideDeregisteredViewConstraint = [deregisteredView autoSetDimension:ALDimensionHeight toSize:0];
     self.hideDeregisteredViewConstraint.priority = UILayoutPriorityRequired;
 
+    ReminderView *outageView = [ReminderView
+        nagWithText:NSLocalizedString(@"OUTAGE_WARNING", @"Label warning the user that the Signal service may be down.")
+          tapAction:nil];
+    [reminderStackView addArrangedSubview:outageView];
+    self.outageViewConstraint = [outageView autoSetDimension:ALDimensionHeight toSize:0];
+    self.outageViewConstraint.priority = UILayoutPriorityRequired;
+
     ReminderView *archiveReminderView =
         [ReminderView explanationWithText:NSLocalizedString(@"INBOX_VIEW_ARCHIVE_MODE_REMINDER",
                                               @"Label reminding the user that they are in archive mode.")];
@@ -291,16 +310,19 @@ NSString *const kArchivedConversationsReuseIdentifier = @"kArchivedConversations
     BOOL shouldHideArchiveReminderView = self.homeViewMode != HomeViewMode_Archive;
     BOOL shouldHideMissingContactsPermissionView = !self.shouldShowMissingContactsPermissionView;
     BOOL shouldHideDeregisteredView = !TSAccountManager.sharedInstance.isDeregistered;
+    BOOL shouldHideOutageView = !OutageDetection.sharedManager.hasOutage;
 
     if (self.hideArchiveReminderViewConstraint.active == shouldHideArchiveReminderView
         && self.hideMissingContactsPermissionViewConstraint.active == shouldHideMissingContactsPermissionView
-        && self.hideDeregisteredViewConstraint.active == shouldHideDeregisteredView) {
+        && self.hideDeregisteredViewConstraint.active == shouldHideDeregisteredView
+        && self.outageViewConstraint.active == shouldHideOutageView) {
         return;
     }
 
     self.hideArchiveReminderViewConstraint.active = shouldHideArchiveReminderView;
     self.hideMissingContactsPermissionViewConstraint.active = shouldHideMissingContactsPermissionView;
     self.hideDeregisteredViewConstraint.active = shouldHideDeregisteredView;
+    self.outageViewConstraint.active = shouldHideOutageView;
 
     [self.view setNeedsLayout];
     [self.view layoutSubviews];

Signal/translations/en.lproj/Localizable.strings

@@ -1405,6 +1405,9 @@
 /* Info Message when {{other user}} updates message expiration to {{time amount}}, see the *_TIME_AMOUNT strings for context. */
 "OTHER_UPDATED_DISAPPEARING_MESSAGES_CONFIGURATION" = "%@ set disappearing message time to %@.";
 
+/* Label warning the user that the Signal service may be down. */
+"OUTAGE_WARNING" = "Signal is experiencing technical difficulties. We are working hard to restore service as quickly as possible.";
+
 /* No comment provided by engineer. */
 "OUTGOING_CALL" = "Outgoing call";
 

SignalServiceKit/src/Network/OutageDetection.swift

@@ -10,10 +10,15 @@ public class OutageDetection: NSObject {
     @objc(sharedManager)
     public static let shared = OutageDetection()
 
+    @objc public static let outageStateDidChange = Notification.Name("OutageStateDidChange")
+
     // These properties should only be accessed on the main thread.
-    private var hasOutage = false {
+    @objc
+    public var hasOutage = false {
         didSet {
             SwiftAssertIsOnMainThread(#function)
+
+            NotificationCenter.default.postNotificationNameAsync(OutageDetection.outageStateDidChange, object: nil)
         }
     }
     private var mayHaveOutage = false {
@@ -23,7 +28,14 @@ public class OutageDetection: NSObject {
             ensureCheckTimer()
         }
     }
+<<<<<<< HEAD
 
+||||||| merged common ancestors
+
+=======
+
+    // We want to be conversative and only
+>>>>>>> Outage detection.
     private func checkForOutageSync() -> Bool {
         let host = CFHostCreateWithName(nil, "uptime.signal.org" as CFString).takeRetainedValue()
         CFHostStartInfoResolution(host, .addresses, nil)
@@ -42,9 +54,14 @@ public class OutageDetection: NSObject {
             if getnameinfo(address.bytes.assumingMemoryBound(to: sockaddr.self), socklen_t(address.length),
                            &hostname, socklen_t(hostname.count), nil, 0, NI_NUMERICHOST) == 0 {
                 let addressString = String(cString: hostname)
-                if addressString != "127.0.0.1" {
-                    Logger.verbose("\(logTag) addressString: \(addressString)")
+                let kHealthyAddress = "127.0.0.1"
+                let kOutageAddress = "127.0.0.2"
+                if addressString == kHealthyAddress {
+                    // Do nothing.
+                } else if addressString == kOutageAddress {
                     isOutageDetected = true
+                } else {
+                    owsFail("\(logTag) unexpected address: \(addressString)")
                 }
             }
         }