Cloud Logging in Flutter

Question

I want to use Cloud Logging in Flutter mobile app. Also, I will link the Cloud Logging with Firebase.

Is there any way to help me to use Cloud Logging in Flutter?

Answer 1

My solution looks like this: create a service account that can access only logging. I created a service account named logger, and added "logs writer" permission. It contains only the ability to write logs:

Add the service account key as logger.json in the assets folder.

Then the following to pubspec.yaml:

...
dependencies:
  flutter:
    sdk: flutter
...
  googleapis: ^9.2.0
  googleapis_auth: ^1.3.1
...
flutter:
...
  assets:
    - logger.json
...

Then a minimal working example:

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:googleapis/logging/v2.dart';
import 'package:googleapis_auth/auth_io.dart';

late final LoggingApi logger;

Future<void> logEvent(String descr) async {
  final Map<String, String> params = {'message': descr};
  final logEntry = LogEntry(
      logName: 'projects/<project-id>/logs/test-log',
      jsonPayload: params,
      resource: MonitoredResource(type: 'global'),
      labels: {'isWeb': '0'});
  final req = WriteLogEntriesRequest(entries: [logEntry]);
  logger.entries.write(req);
}

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  final f = await rootBundle.loadString('assets/logger.json');
  AutoRefreshingAuthClient httpClient = await clientViaServiceAccount(
      ServiceAccountCredentials.fromJson(String.fromCharCodes(f.codeUnits)), [
    LoggingApi.loggingWriteScope,
  ]);

  logger = LoggingApi(httpClient);
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});
  @override
  Widget build(BuildContext context) => const MaterialApp(home: MyHomePage());
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key});

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    logEvent('test log no. $_counter');
    setState(() => _counter++);
  }

  @override
  Widget build(BuildContext context) => Scaffold(
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              const Text('You have pushed the button this many times:'),
              Text(
                '$_counter',
                style: Theme.of(context).textTheme.headline4,
              ),
            ],
          ),
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: _incrementCounter,
          tooltip: 'Increment',
          child: const Icon(Icons.add),
        ),
      );
}

In general, adding a service account as an asset is considered unsafe. But since this can only write log entries, it doesn't matter that much I guess. You may consider encoding it, or adding it to storage with the right permission rules.