feat: add configuration objects for TopicClient

README.md

@@ -19,6 +19,11 @@ and the Flutter guide for
 4. `brew info dart` to determine where the dart sdk is installed
 5. followed [these](https://fluttermaster.com/config-dart-sdk-inside-intellij-idea-on-macos/) instructions on how to setup sdk inside of intellij
 
+In VSCode, there's an extension for Dart and Flutter files.
+To install dependencies using CLI: `dart pub get`
+Running tests: `dart test`
+Linting and formatting: `dart format` and `dart fix`
+
 TODO: Put a short description of the package here that helps potential users
 know whether this package might be useful for them.
 
@@ -40,6 +45,17 @@ to `/example` folder.
 const like = 'sample';
 ```
 
+## Logging
+
+We use the [Dart logging package](https://github.com/dart-lang/logging) to create internal Loggers for producing Momento-related logs. The default logger does not do anything with the logs, so you must configure the logging level and handler at the beginning of your program:
+
+```
+Logger.root.level = Level.ALL; // defaults to Level.INFO
+Logger.root.onRecord.listen((record) {
+  print('${record.level.name}: ${record.time}: ${record.message}');
+});
+```
+
 ## Additional information
 
 TODO: Tell users more about the package: where to find more information, how to 

lib/src/config/topic_configuration.dart

@@ -0,0 +1,37 @@
+import 'transport/grpc_configuration.dart';
+import 'transport/transport_strategy.dart';
+
+abstract interface class TopicConfiguration {
+  /// Configures low-level options for network interactions with the Momento service
+  late TransportStrategy transportStrategy;
+
+  /// Constructor for a TopicConfiguration
+  TopicConfiguration(this.transportStrategy);
+
+  /// Copy constructor for overriding TransportStrategy
+  TopicConfiguration withTransportStrategy(TransportStrategy transportStrategy);
+
+  /// Convenience copy constructor that updates the client-side 
+  /// timeout setting in the transport strategy
+  TopicConfiguration withDeadline(Duration deadline);
+}
+
+/// Configuration options for Momento TopicClient.
+/// The easiest way to get a `TopicClientConfiguration` object is 
+/// to use one of the prebuilt TopicClientConfigurations classes.
+class TopicClientConfiguration implements TopicConfiguration {
+  @override
+  late TransportStrategy transportStrategy;
+
+  TopicClientConfiguration(this.transportStrategy);
+
+  @override
+  TopicConfiguration withTransportStrategy(TransportStrategy transportStrategy) {
+    return TopicClientConfiguration(transportStrategy);
+  }
+
+  @override
+  TopicConfiguration withDeadline(Duration deadline) {
+    return TopicClientConfiguration(StaticTransportStrategy(StaticGrpcConfiguration(deadline)));
+  }
+}

lib/src/config/topic_configurations.dart

@@ -0,0 +1,17 @@
+import 'topic_configuration.dart';
+import 'transport/grpc_configuration.dart';
+import 'transport/transport_strategy.dart';
+
+/// Prebuilt configurations for Momento Topics clients
+sealed class TopicClientConfigurations {}
+
+/// Provides prebuilt configurations for the `TopicClient` on mobile platforms
+sealed class Mobile extends TopicClientConfigurations {
+  static TopicClientConfiguration defaultConfig() {
+    return latest();
+  }
+
+  static TopicClientConfiguration latest() {
+    return TopicClientConfiguration(StaticTransportStrategy(StaticGrpcConfiguration(Duration(seconds: 15))));;
+  }
+}

lib/src/config/transport/grpc_configuration.dart

@@ -0,0 +1,21 @@
+abstract interface class GrpcConfiguration {
+  /// Duration of time the client is willing to wait for an RPC to 
+  /// complete before it is terminated with a DeadlineExceeded error
+  late Duration deadline;
+
+  /// Copy constructor for overriding the client-side deadline
+  GrpcConfiguration withDeadline(Duration deadline);
+}
+
+/// Encapsulates gRPC configuration tunables
+class StaticGrpcConfiguration implements GrpcConfiguration {
+  @override
+  late Duration deadline;
+
+  StaticGrpcConfiguration(this.deadline);
+
+  @override
+  GrpcConfiguration withDeadline(Duration deadline) {
+    return StaticGrpcConfiguration(deadline);
+  }
+}

lib/src/config/transport/transport_strategy.dart

@@ -0,0 +1,30 @@
+import 'grpc_configuration.dart';
+
+abstract interface class TransportStrategy {
+  /// Low-level gRPC settings for communication with the Momento server
+  late GrpcConfiguration grpcConfig;
+
+  /// Copy constructor to update the client-side timeout
+  TransportStrategy withGrpcConfig(GrpcConfiguration grpcConfig);
+
+  /// Copy constructor to update the client-side timeout
+  TransportStrategy withClientTimeout(Duration timeout);
+}
+
+class StaticTransportStrategy implements TransportStrategy {
+  @override
+  late GrpcConfiguration grpcConfig;
+
+  StaticTransportStrategy(this.grpcConfig);
+
+  @override
+  TransportStrategy withClientTimeout(Duration timeout) {
+    return StaticTransportStrategy(StaticGrpcConfiguration(timeout));
+  }
+
+  @override
+  TransportStrategy withGrpcConfig(GrpcConfiguration grpcConfig) {
+    return StaticTransportStrategy(grpcConfig);
+  }
+
+}

lib/src/topic_client.dart

@@ -1,4 +1,5 @@
 import 'package:client_sdk_dart/src/auth/credential_provider.dart';
+import 'package:logging/logging.dart';
 import 'internal/pubsub_client.dart';
 import 'messages/Values.dart';
 import 'messages/responses/topics/topic_publish.dart';
@@ -10,6 +11,7 @@ abstract class ITopicClient {
 class TopicClient implements ITopicClient {
   ClientPubsub _pubsubClient;
   CredentialProvider _credentialProvider;
+  final Logger _logger = Logger('MomentoTopicClient');
 
   TopicClient(this._credentialProvider) : _pubsubClient = ClientPubsub(_credentialProvider);
 

pubspec.yaml

@@ -10,6 +10,7 @@ environment:
 dependencies:
   grpc: ^3.2.4
   jwt_decoder: ^2.0.1
+  logging: ^1.2.0
   protobuf: ^3.1.0
   string_validator: ^1.0.2
   # path: ^1.8.0