Add support for logging

CHANGELOG.md

@@ -40,6 +40,8 @@
 * Support user profile data. ([#570](https://github.com/realm/realm-dart/pull/570))
 * Support flexible synchronization. ([#496](https://github.com/realm/realm-dart/pull/496))
 * Added support for DateTime properties. ([#569](https://github.com/realm/realm-dart/pull/569))
+* Support setting logger on AppConfiguration. ([#583](https://github.com/realm/realm-dart/pull/583))
+* Support setting logger on Realm class. Default is to print info message or worse to the console. ([#583](https://github.com/realm/realm-dart/pull/583))
 
 ### Fixed
 * Fixed an issue that would result in the wrong transaction being rolled back if you start a write transaction inside a write transaction. ([#442](https://github.com/realm/realm-dart/issues/442))

ffigen/config.yaml

@@ -10,13 +10,15 @@ headers:
     - 'realm_android_platform.h'
     - 'subscription_set.h'
     - 'sync_session.h'
+    - 'sync_client_config.h'
   include-directives: #generate only for these headers
     - 'realm.h'
     - 'realm_dart.h'
     - 'realm_dart_scheduler.h'
     - 'realm_android_platform.h'
     - 'subscription_set.h'
     - 'sync_session.h'
+    - 'sync_client_config.h'
 compiler-opts:
   - '-DRLM_NO_ANON_UNIONS'
   - '-DFFI_GEN'

ffigen/sync_client_config.h

@@ -0,0 +1 @@
+../src/sync_client_config.h

lib/src/app.dart

@@ -15,49 +15,16 @@
 // limitations under the License.
 //
 ////////////////////////////////////////////////////////////////////////////////
-
 import 'dart:io';
+
+import 'package:logging/logging.dart';
 import 'package:meta/meta.dart';
-import 'native/realm_core.dart';
+
+import '../realm.dart';
+import 'configuration.dart';
 import 'credentials.dart';
+import 'native/realm_core.dart';
 import 'user.dart';
-import 'configuration.dart';
-
-/// Specifies the criticality level above which messages will be logged
-/// by the default sync client logger.
-/// {@category Application}
-enum LogLevel {
-  /// Log everything. This will seriously harm the performance of the
-  /// sync client and should never be used in production scenarios.
-  all,
-
-  /// A version of 'debug' that allows for very high volume output.
-  /// This may seriously affect the performance of the sync client.
-  trace,
-
-  /// Reveal information that can aid debugging, no longer paying
-  /// attention to efficiency.
-  debug,
-
-  /// Same as 'Info', but prioritize completeness over minimalism.
-  detail,
-
-  /// Log operational sync client messages, but in a minimalistic fashion to
-  /// avoid general overhead from logging and to keep volume down.
-  info,
-
-  /// Log errors and warnings.
-  warn,
-
-  /// Log errors only.
-  error,
-
-  /// Log only fatal errors.
-  fatal,
-
-  /// Log nothing.
-  off,
-}
 
 /// A class exposing configuration options for an [App]
 /// {@category Application}
@@ -111,9 +78,6 @@ class AppConfiguration {
   /// Setting this will not change the encryption key for individual Realms, which is set in the [Configuration].
   final List<int>? metadataEncryptionKey;
 
-  /// The [LogLevel] for sync operations.
-  final LogLevel logLevel;
-
   /// The [HttpClient] that will be used for HTTP requests during authentication.
   ///
   /// You can use this to override the default http client handler and configure settings like proxies,
@@ -132,7 +96,6 @@ class AppConfiguration {
     this.localAppVersion,
     this.metadataEncryptionKey,
     this.metadataPersistenceMode = MetadataPersistenceMode.plaintext,
-    this.logLevel = LogLevel.error,
     this.maxConnectionTimeout = const Duration(minutes: 2),
     HttpClient? httpClient,
   })  : baseUrl = baseUrl ?? Uri.parse('https://realm.mongodb.com'),

lib/src/native/realm_bindings.dart

@@ -3134,6 +3134,40 @@ class RealmLibrary {
   late final _realm_dart_scheduler_invoke = _realm_dart_scheduler_invokePtr
       .asFunction<void Function(int, ffi.Pointer<ffi.Void>)>();
 
+  void realm_dart_sync_client_config_set_log_callback(
+    ffi.Pointer<realm_sync_client_config_t> config,
+    realm_log_func_t callback,
+    ffi.Pointer<ffi.Void> userdata,
+    realm_free_userdata_func_t userdata_free,
+    ffi.Pointer<realm_scheduler_t> scheduler,
+  ) {
+    return _realm_dart_sync_client_config_set_log_callback(
+      config,
+      callback,
+      userdata,
+      userdata_free,
+      scheduler,
+    );
+  }
+
+  late final _realm_dart_sync_client_config_set_log_callbackPtr = _lookup<
+          ffi.NativeFunction<
+              ffi.Void Function(
+                  ffi.Pointer<realm_sync_client_config_t>,
+                  realm_log_func_t,
+                  ffi.Pointer<ffi.Void>,
+                  realm_free_userdata_func_t,
+                  ffi.Pointer<realm_scheduler_t>)>>(
+      'realm_dart_sync_client_config_set_log_callback');
+  late final _realm_dart_sync_client_config_set_log_callback =
+      _realm_dart_sync_client_config_set_log_callbackPtr.asFunction<
+          void Function(
+              ffi.Pointer<realm_sync_client_config_t>,
+              realm_log_func_t,
+              ffi.Pointer<ffi.Void>,
+              realm_free_userdata_func_t,
+              ffi.Pointer<realm_scheduler_t>)>();
+
   /// Register a handler in order to be notified when subscription set is equal to the one passed as parameter
   /// This is an asynchronous operation.
   ///
@@ -3145,7 +3179,7 @@ class RealmLibrary {
   bool realm_dart_sync_on_subscription_set_state_change_async(
     ffi.Pointer<realm_flx_sync_subscription_set_t> subscription_set,
     int notify_when,
-    realm_dart_sync_on_subscription_state_changed callback,
+    realm_sync_on_subscription_state_changed_t callback,
     ffi.Pointer<ffi.Void> userdata,
     realm_free_userdata_func_t userdata_free,
     ffi.Pointer<realm_scheduler_t> scheduler,
@@ -3167,7 +3201,7 @@ class RealmLibrary {
                   ffi.Uint8 Function(
                       ffi.Pointer<realm_flx_sync_subscription_set_t>,
                       ffi.Int32,
-                      realm_dart_sync_on_subscription_state_changed,
+                      realm_sync_on_subscription_state_changed_t,
                       ffi.Pointer<ffi.Void>,
                       realm_free_userdata_func_t,
                       ffi.Pointer<realm_scheduler_t>)>>(
@@ -3177,7 +3211,7 @@ class RealmLibrary {
           int Function(
               ffi.Pointer<realm_flx_sync_subscription_set_t>,
               int,
-              realm_dart_sync_on_subscription_state_changed,
+              realm_sync_on_subscription_state_changed_t,
               ffi.Pointer<ffi.Void>,
               realm_free_userdata_func_t,
               ffi.Pointer<realm_scheduler_t>)>();
@@ -9097,12 +9131,22 @@ class _SymbolAddresses {
               ffi.Void Function(ffi.Uint64, ffi.Pointer<ffi.Void>)>>
       get realm_dart_scheduler_invoke =>
           _library._realm_dart_scheduler_invokePtr;
+  ffi.Pointer<
+          ffi.NativeFunction<
+              ffi.Void Function(
+                  ffi.Pointer<realm_sync_client_config_t>,
+                  realm_log_func_t,
+                  ffi.Pointer<ffi.Void>,
+                  realm_free_userdata_func_t,
+                  ffi.Pointer<realm_scheduler_t>)>>
+      get realm_dart_sync_client_config_set_log_callback =>
+          _library._realm_dart_sync_client_config_set_log_callbackPtr;
   ffi.Pointer<
           ffi.NativeFunction<
               ffi.Uint8 Function(
                   ffi.Pointer<realm_flx_sync_subscription_set_t>,
                   ffi.Int32,
-                  realm_dart_sync_on_subscription_state_changed,
+                  realm_sync_on_subscription_state_changed_t,
                   ffi.Pointer<ffi.Void>,
                   realm_free_userdata_func_t,
                   ffi.Pointer<realm_scheduler_t>)>>
@@ -9470,8 +9514,6 @@ abstract class realm_column_attr {
 class realm_config extends ffi.Opaque {}
 
 typedef realm_config_t = realm_config;
-typedef realm_dart_sync_on_subscription_state_changed = ffi.Pointer<
-    ffi.NativeFunction<ffi.Void Function(ffi.Pointer<ffi.Void>, ffi.Int32)>>;
 typedef realm_data_initialization_func_t = ffi.Pointer<
     ffi.NativeFunction<
         ffi.Uint8 Function(ffi.Pointer<ffi.Void>, ffi.Pointer<realm_t>)>>;

lib/src/native/realm_core.dart

@@ -23,6 +23,7 @@ import 'dart:typed_data';
 
 // Hide StringUtf8Pointer.toNativeUtf8 and StringUtf16Pointer since these allows silently allocating memory. Use toUtf8Ptr instead
 import 'package:ffi/ffi.dart' hide StringUtf8Pointer, StringUtf16Pointer;
+import 'package:logging/logging.dart';
 
 import '../app.dart';
 import '../collections.dart';
@@ -1026,13 +1027,36 @@ class _RealmCore {
     });
   }
 
+  static void _logCallback(Pointer<Void> userdata, int levelAsInt, Pointer<Int8> message) {
+    try {
+      final logger = Realm.logger;
+      final level = _LogLevel.values[levelAsInt].loggerLevel;
+
+      // Don't do expensive utf8 to utf16 conversion unless we have to..
+      if (logger.isLoggable(level)) {
+        logger.log(level, message.cast<Utf8>().toDartString());
+      }
+    } finally {
+      _realmLib.realm_free(message.cast()); // .. but always free the message
+    }
+  }
+
   SyncClientConfigHandle _createSyncClientConfig(AppConfiguration configuration) {
     return using((arena) {
       final handle = SyncClientConfigHandle._(_realmLib.realm_sync_client_config_new());
 
       _realmLib.realm_sync_client_config_set_base_file_path(handle._pointer, configuration.baseFilePath.path.toUtf8Ptr(arena));
       _realmLib.realm_sync_client_config_set_metadata_mode(handle._pointer, configuration.metadataPersistenceMode.index);
-      _realmLib.realm_sync_client_config_set_log_level(handle._pointer, configuration.logLevel.index);
+
+      _realmLib.realm_sync_client_config_set_log_level(handle._pointer, _LogLevel.fromLevel(Realm.logger.level).index);
+      _realmLib.realm_dart_sync_client_config_set_log_callback(
+        handle._pointer,
+        Pointer.fromFunction(_logCallback),
+        nullptr,
+        nullptr,
+        scheduler.handle._pointer,
+      );
+
       _realmLib.realm_sync_client_config_set_connect_timeout(handle._pointer, configuration.maxConnectionTimeout.inMicroseconds);
       if (configuration.metadataEncryptionKey != null && configuration.metadataPersistenceMode == MetadataPersistenceMode.encrypted) {
         _realmLib.realm_sync_client_config_set_metadata_encryption_key(handle._pointer, configuration.metadataEncryptionKey!.toUint8Ptr(arena));
@@ -1970,3 +1994,26 @@ extension on realm_object_id {
     return ObjectId.fromBytes(buffer);
   }
 }
+
+// Helper enum for converting Level
+enum _LogLevel {
+  all(RealmLogLevel.all),
+  trace(RealmLogLevel.trace),
+  debug(RealmLogLevel.debug),
+  detail(RealmLogLevel.detail),
+  info(RealmLogLevel.info),
+  warn(RealmLogLevel.warn),
+  error(RealmLogLevel.error),
+  fatal(RealmLogLevel.fatal),
+  off(RealmLogLevel.off);
+
+  final Level loggerLevel;
+  const _LogLevel(this.loggerLevel);
+
+  factory _LogLevel.fromLevel(Level level) {
+    for (final candidate in _LogLevel.values) {
+      if (level.value > candidate.loggerLevel.value) return candidate;
+    }
+    return _LogLevel.off;
+  }
+}

lib/src/realm_class.dart

@@ -21,6 +21,7 @@ import 'dart:ffi';
 import 'dart:io';
 import 'dart:isolate';
 
+import 'package:logging/logging.dart';
 import 'package:realm_common/realm_common.dart';
 
 import 'configuration.dart';
@@ -70,6 +71,72 @@ export 'subscription.dart' show Subscription, SubscriptionSet, SubscriptionSetSt
 export 'user.dart' show User, UserState, UserIdentity;
 export 'session.dart' show Session, SessionState, ConnectionState, ProgressDirection, ProgressMode, SyncProgress;
 
+/// Specifies the criticality level above which messages will be logged
+/// by the default sync client logger.
+/// {@category Realm}
+class RealmLogLevel {
+  /// Log everything. This will seriously harm the performance of the
+  /// sync client and should never be used in production scenarios.
+  ///
+  /// Same as [Level.ALL]
+  static const all = Level.ALL;
+
+  /// A version of [debug] that allows for very high volume output.
+  /// This may seriously affect the performance of the sync client.
+  ///
+  /// Same as [Level.FINEST]
+  static const trace = Level('TRACE', 300);
+
+  /// Reveal information that can aid debugging, no longer paying
+  /// attention to efficiency.
+  ///
+  /// Same as [Level.FINER]
+  static const debug = Level('DEBUG', 400);
+
+  /// Same as [info], but prioritize completeness over minimalism.
+  ///
+  /// Same as [Level.FINE];
+  static const detail = Level('DETAIL', 500);
+
+  /// Log operational sync client messages, but in a minimalist fashion to
+  /// avoid general overhead from logging and to keep volume down.
+  ///
+  /// Same as [Level.INFO];
+  static const info = Level.INFO;
+
+  /// Log errors and warnings.
+  ///
+  /// Same as [Level.WARNING];
+  static const warn = Level.WARNING;
+
+  /// Log errors only.
+  ///
+  /// Same as [Level.SEVERE];
+  static const error = Level('ERROR', 1000);
+
+  /// Log only fatal errors.
+  ///
+  /// Same as [Level.SHOUT];
+  static const fatal = Level('FATAL', 1200);
+
+  /// Log nothing.
+  ///
+  /// Same as [Level.OFF];
+  static const off = Level.OFF;
+
+  static const levels = [
+    all,
+    trace,
+    debug,
+    detail,
+    info,
+    warn,
+    error,
+    fatal,
+    off,
+  ];
+}
+
 /// A [Realm] instance represents a `Realm` database.
 ///
 /// {@category Realm}
@@ -79,6 +146,13 @@ class Realm {
   late final RealmHandle _handle;
   late final Scheduler _scheduler;
 
+  /// The logger to use.
+  ///
+  /// Defaults to printing info or worse to the console
+  static late var logger = Logger.detached('Realm')
+    ..level = RealmLogLevel.info
+    ..onRecord.listen((event) => print(event));
+
   /// The [Configuration] object used to open this [Realm]
   Configuration get config => _config;
 
@@ -342,6 +416,8 @@ class Scheduler {
   }
 }
 
+late final scheduler = Scheduler(() {});
+
 /// @nodoc
 class Transaction {
   Realm? _realm;

src/CMakeLists.txt

@@ -12,6 +12,7 @@ set(SOURCES
     realm_dart_scheduler.cpp
     subscription_set.cpp
     sync_session.cpp
+    sync_client_config.cpp
 )
 
 set(HEADERS
@@ -20,6 +21,7 @@ set(HEADERS
     realm-core/src/realm.h
     subscription_set.h
     sync_session.h
+    sync_client_config.h
 )
 
 add_library(realm_dart SHARED ${SOURCES} ${HEADERS})