RDART-1081: Expose sync timeout options (#1764)

* Expose sync timeout options

* CR comments

* Format

Author: nirinchev

CHANGELOG.md

@@ -1,10 +1,12 @@
 ## vNext (TBD)
 
 ### Enhancements
-* None
+* Added a new parameter of type `SyncTimeoutOptions` to `AppConfiguration`. It allows users to control sync timings, such as ping/pong intervals as well various connection timeouts. (Issue [#1763](https://github.com/realm/realm-dart/issues/1763))
+* Added a new parameter `cancelAsyncOperationsOnNonFatalErrors` on `Configuration.flexibleSync` that allows users to control whether non-fatal errors such as connection timeouts should be surfaced in the form of errors or if sync should try and reconnect in the background. (PR [#1764](https://github.com/realm/realm-dart/pull/1764))
 
 ### Fixed
 * Fixed an issue where creating a flexible sync configuration with an embedded object not referenced by any top-level object would throw a "No such table" exception with no meaningful information about the issue. Now a `RealmException` will be thrown that includes the offending object name, as well as more precise text for what the root cause of the error is. (PR [#1748](https://github.com/realm/realm-dart/pull/1748))
+* `AppConfiguration.maxConnectionTimeout` never had any effect and has been deprecated in favor of `SyncTimeoutOptions.connectTimeout`. (PR [#1764](https://github.com/realm/realm-dart/pull/1764))
 * Pure dart apps, when compiled to an exe and run from outside the project directory would fail to load the native shared library. (Issue [#1765](https://github.com/realm/realm-dart/issues/1765))
 
 ### Compatibility

packages/realm_dart/lib/src/app.dart

@@ -15,6 +15,78 @@ import 'handles/realm_core.dart';
 import 'logging.dart';
 import 'user.dart';
 
+/// Options for configuring timeouts and intervals used by the sync client.
+@immutable
+final class SyncTimeoutOptions {
+  /// Controls the maximum amount of time to allow for a connection to
+  /// become fully established.
+  ///
+  /// This includes the time to resolve the
+  /// network address, the TCP connect operation, the SSL handshake, and
+  /// the WebSocket handshake.
+  ///
+  /// Defaults to 2 minutes.
+  final Duration connectTimeout; // TimeSpan.FromMinutes(2);
+
+  /// Controls the amount of time to keep a connection open after all
+  /// sessions have been abandoned.
+  ///
+  /// After all synchronized Realms have been closed for a given server, the
+  /// connection is kept open until the linger time has expired to avoid the
+  /// overhead of reestablishing the connection when Realms are being closed and
+  /// reopened.
+  ///
+  /// Defaults to 30 seconds.
+  final Duration connectionLingerTime;
+
+  /// Controls how long to wait between each heartbeat ping message.
+  ///
+  /// The client periodically sends ping messages to the server to check if the
+  /// connection is still alive. Shorter periods make connection state change
+  /// notifications more responsive at the cost of battery life (as the antenna
+  /// will have to wake up more often).
+  ///
+  /// Defaults to 1 minute.
+  final Duration pingKeepAlivePeriod;
+
+  /// Controls how long to wait for a reponse to a heartbeat ping before
+  /// concluding that the connection has dropped.
+  ///
+  /// Shorter values will make connection state change notifications more
+  /// responsive as it will only change to `disconnected` after this much time has
+  /// elapsed, but overly short values may result in spurious disconnection
+  /// notifications when the server is simply taking a long time to respond.
+  ///
+  /// Defaults to 2 minutes.
+  final Duration pongKeepAliveTimeout;
+
+  /// Controls the maximum amount of time since the loss of a
+  /// prior connection, for a new connection to be considered a "fast
+  /// reconnect".
+  ///
+  /// When a client first connects to the server, it defers uploading any local
+  /// changes until it has downloaded all changesets from the server. This
+  /// typically reduces the total amount of merging that has to be done, and is
+  /// particularly beneficial the first time that a specific client ever connects
+  /// to the server.
+  ///
+  /// When an existing client disconnects and then reconnects within the "fact
+  /// reconnect" time this is skipped and any local changes are uploaded
+  /// immediately without waiting for downloads, just as if the client was online
+  /// the whole time.
+  ///
+  /// Defaults to 1 minute.
+  final Duration fastReconnectLimit;
+
+  const SyncTimeoutOptions({
+    this.connectTimeout = const Duration(minutes: 2),
+    this.connectionLingerTime = const Duration(seconds: 30),
+    this.pingKeepAlivePeriod = const Duration(minutes: 1),
+    this.pongKeepAliveTimeout = const Duration(minutes: 2),
+    this.fastReconnectLimit = const Duration(minutes: 1),
+  });
+}
+
 /// A class exposing configuration options for an [App]
 /// {@category Application}
 @immutable
@@ -41,6 +113,7 @@ class AppConfiguration {
   /// become fully established. This includes the time to resolve the
   /// network address, the TCP connect operation, the SSL handshake, and
   /// the WebSocket handshake. Defaults to 2 minutes.
+  @Deprecated('Use SyncTimeoutOptions.connectTimeout')
   final Duration maxConnectionTimeout;
 
   /// Enumeration that specifies how and if logged-in User objects are persisted across application launches.
@@ -61,6 +134,9 @@ class AppConfiguration {
   /// a more complex networking setup.
   final Client httpClient;
 
+  /// Options for the assorted types of connection timeouts for sync connections opened for this app.
+  final SyncTimeoutOptions syncTimeoutOptions;
+
   /// Instantiates a new [AppConfiguration] with the specified appId.
   AppConfiguration(
     this.appId, {
@@ -69,8 +145,9 @@ class AppConfiguration {
     this.defaultRequestTimeout = const Duration(seconds: 60),
     this.metadataEncryptionKey,
     this.metadataPersistenceMode = MetadataPersistenceMode.plaintext,
-    this.maxConnectionTimeout = const Duration(minutes: 2),
+    @Deprecated('Use SyncTimeoutOptions.connectTimeout') this.maxConnectionTimeout = const Duration(minutes: 2),
     Client? httpClient,
+    this.syncTimeoutOptions = const SyncTimeoutOptions(),
   })  : baseUrl = baseUrl ?? Uri.parse(realmCore.getDefaultBaseUrl()),
         baseFilePath = baseFilePath ?? path.dirname(Configuration.defaultRealmPath),
         httpClient = httpClient ?? defaultClient {

packages/realm_dart/lib/src/configuration.dart

@@ -187,6 +187,7 @@ abstract class Configuration {
     int? maxNumberOfActiveVersions,
     ShouldCompactCallback? shouldCompactCallback,
     int schemaVersion = 0,
+    bool cancelAsyncOperationsOnNonFatalErrors = false,
   }) =>
       FlexibleSyncConfiguration._(
         user,
@@ -199,6 +200,7 @@ abstract class Configuration {
         maxNumberOfActiveVersions: maxNumberOfActiveVersions,
         shouldCompactCallback: shouldCompactCallback,
         schemaVersion: schemaVersion,
+        cancelAsyncOperationsOnNonFatalErrors: cancelAsyncOperationsOnNonFatalErrors,
       );
 
   /// Constructs a [DisconnectedSyncConfiguration]
@@ -351,6 +353,14 @@ class FlexibleSyncConfiguration extends Configuration {
   /// all subscriptions will be reset since they may not conform to the new schema.
   final int schemaVersion;
 
+  /// Controls whether async operations such as [Realm.open], [Session.waitForUpload], and [Session.waitForDownload]
+  /// should throw an error whenever a non-fatal error, such as timeout occurs.
+  ///
+  /// If set to `false`, non-fatal session errors will be ignored and sync will continue retrying the
+  /// connection under in the background. This means that in cases where the devie is offline, these operations
+  /// may take an indeterminate time to complete.
+  final bool cancelAsyncOperationsOnNonFatalErrors;
+
   FlexibleSyncConfiguration._(
     this.user,
     super.schemaObjects, {
@@ -362,6 +372,7 @@ class FlexibleSyncConfiguration extends Configuration {
     super.maxNumberOfActiveVersions,
     this.shouldCompactCallback,
     this.schemaVersion = 0,
+    this.cancelAsyncOperationsOnNonFatalErrors = false,
   }) : super._();
 
   @override

packages/realm_dart/lib/src/handles/native/app_handle.dart

@@ -438,6 +438,13 @@ _AppConfigHandle _createAppConfig(AppConfiguration configuration, HttpTransportH
       realmLib.realm_app_config_set_metadata_encryption_key(handle.pointer, configuration.metadataEncryptionKey!.toUint8Ptr(arena));
     }
 
+    final syncClientConfig = realmLib.realm_app_config_get_sync_client_config(handle.pointer);
+    realmLib.realm_sync_client_config_set_connect_timeout(syncClientConfig, configuration.syncTimeoutOptions.connectTimeout.inMilliseconds);
+    realmLib.realm_sync_client_config_set_connection_linger_time(syncClientConfig, configuration.syncTimeoutOptions.connectionLingerTime.inMilliseconds);
+    realmLib.realm_sync_client_config_set_ping_keepalive_period(syncClientConfig, configuration.syncTimeoutOptions.pingKeepAlivePeriod.inMilliseconds);
+    realmLib.realm_sync_client_config_set_pong_keepalive_timeout(syncClientConfig, configuration.syncTimeoutOptions.pongKeepAliveTimeout.inMilliseconds);
+    realmLib.realm_sync_client_config_set_fast_reconnect_limit(syncClientConfig, configuration.syncTimeoutOptions.fastReconnectLimit.inMilliseconds);
+
     return handle;
   });
 }

packages/realm_dart/lib/src/handles/native/config_handle.dart

@@ -91,6 +91,8 @@ class ConfigHandle extends HandleBase<realm_config> {
         try {
           realmLib.realm_sync_config_set_session_stop_policy(syncConfigPtr, config.sessionStopPolicy.index);
           realmLib.realm_sync_config_set_resync_mode(syncConfigPtr, config.clientResetHandler.clientResyncMode.index);
+          realmLib.realm_sync_config_set_cancel_waits_on_nonfatal_error(syncConfigPtr, config.cancelAsyncOperationsOnNonFatalErrors);
+
           final errorHandlerCallback =
               Pointer.fromFunction<Void Function(Handle, Pointer<realm_sync_session_t>, realm_sync_error_t)>(_syncErrorHandlerCallback);
           final errorHandlerUserdata = realmLib.realm_dart_userdata_async_new(config, errorHandlerCallback.cast(), schedulerHandle.pointer);

packages/realm_dart/lib/src/realm_class.dart

@@ -59,7 +59,7 @@ export 'package:realm_common/realm_common.dart'
         Uuid;
 
 // always expose with `show` to explicitly control the public API surface
-export 'app.dart' show AppException, App, MetadataPersistenceMode, AppConfiguration;
+export 'app.dart' show AppException, App, MetadataPersistenceMode, AppConfiguration, SyncTimeoutOptions;
 export 'collections.dart' show Move;
 export "configuration.dart"
     show
@@ -179,7 +179,6 @@ class Realm {
       return await CancellableFuture.value(realm, cancellationToken);
     }
 
-
     final asyncOpenHandle = AsyncOpenTaskHandle.from(config);
     return await CancellableFuture.from<Realm>(() async {
       if (cancellationToken != null && cancellationToken.isCancelled) {

packages/realm_dart/test/app_test.dart

@@ -382,6 +382,35 @@ void main() {
   test('AppConfiguration(empty-id) throws', () {
     expect(() => AppConfiguration(''), throwsA(isA<RealmException>()));
   });
+
+  baasTest('AppConfiguration.syncTimeouts are passed correctly to Core', (appConfig) async {
+    Realm.logger.setLogLevel(LogLevel.debug);
+    final buffer = StringBuffer();
+    final sub = Realm.logger.onRecord.listen((r) => buffer.writeln('[${r.category}] ${r.level}: ${r.message}'));
+
+    final customConfig = AppConfiguration(appConfig.appId,
+        baseUrl: appConfig.baseUrl,
+        baseFilePath: appConfig.baseFilePath,
+        defaultRequestTimeout: appConfig.defaultRequestTimeout,
+        syncTimeoutOptions: SyncTimeoutOptions(
+            connectTimeout: Duration(milliseconds: 1234),
+            connectionLingerTime: Duration(milliseconds: 3456),
+            pingKeepAlivePeriod: Duration(milliseconds: 5678),
+            pongKeepAliveTimeout: Duration(milliseconds: 7890),
+            fastReconnectLimit: Duration(milliseconds: 9012)));
+
+    final realm = await getIntegrationRealm(appConfig: customConfig);
+    await realm.syncSession.waitForDownload();
+
+    final log = buffer.toString();
+    expect(log, contains('Config param: connect_timeout = 1234 ms'));
+    expect(log, contains('Config param: connection_linger_time = 3456 ms'));
+    expect(log, contains('Config param: ping_keepalive_period = 5678 ms'));
+    expect(log, contains('Config param: pong_keepalive_timeout = 7890 ms'));
+    expect(log, contains('Config param: fast_reconnect_limit = 9012 ms'));
+
+    await sub.cancel();
+  });
 }
 
 extension PersonExt on Person {

packages/realm_dart/test/baas_helper.dart

@@ -191,7 +191,6 @@ class BaasHelper {
       app.clientAppId,
       baseUrl: Uri.parse(customBaseUrl ?? baseUrl),
       baseFilePath: temporaryPath,
-      maxConnectionTimeout: Duration(minutes: 10),
       defaultRequestTimeout: Duration(minutes: 7),
     );
   }