Add Sentry crash-reporting opt-out (#211)

* Add Sentry opt-out

* [chore] Remove inaccurate comment

* Prevent line-wrap in iOS

lib/main.dart

@@ -2,7 +2,7 @@ import 'dart:async';
 
 import 'package:flutter/cupertino.dart' show CupertinoThemeData, DefaultCupertinoLocalizations;
 import 'package:flutter/material.dart'
-    show BottomSheetThemeData, Colors, DefaultMaterialLocalizations, ThemeData, ThemeMode, MaterialApp, Scaffold;
+    show BottomSheetThemeData, Colors, DefaultMaterialLocalizations, ThemeData, ThemeMode;
 import 'package:flutter/scheduler.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
@@ -15,18 +15,22 @@ import 'package:sentry_flutter/sentry_flutter.dart';
 
 Future<void> main() async {
   usePathUrlStrategy();
-  await SentryFlutter.init(
-    (options) {
-      options.dsn = 'https://96106df405ade3f013187dfc8e4200e7@o920269.ingest.us.sentry.io/4508132321001472';
-      // Capture all traces.  May need to adjust if overwhelming
-      options.tracesSampleRate = 1.0;
-      // For each trace, capture all profiles
-      options.profilesSampleRate = 1.0;
-    },
-    appRunner: () => runApp(Main()),
-  );
 
-  // or define SENTRY_DSN via Dart environment variable (--dart-define)
+  var settings = Settings();
+  if (settings.trackErrors) {
+    await SentryFlutter.init(
+      (options) {
+        options.dsn = 'https://96106df405ade3f013187dfc8e4200e7@o920269.ingest.us.sentry.io/4508132321001472';
+        // Capture all traces.  May need to adjust if overwhelming
+        options.tracesSampleRate = 1.0;
+        // For each trace, capture all profiles
+        options.profilesSampleRate = 1.0;
+      },
+      appRunner: () => runApp(Main()),
+    );
+  } else {
+    runApp(Main());
+  }
 }
 
 //TODO: EventChannel might be better than the stream controller we are using now

lib/screens/SettingsScreen.dart

@@ -85,10 +85,27 @@ class _SettingsScreenState extends State<SettingsScreen> {
           )),
     ));
 
+    items.add(ConfigSection(children: [
+      ConfigItem(
+          label: Text('Report errors automatically'),
+          labelWidth: 250,
+          content: Align(
+              alignment: Alignment.centerRight,
+              child: Switch.adaptive(
+                materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
+                value: settings.trackErrors,
+                onChanged: (value) {
+                  setState(() {
+                    settings.trackErrors = value;
+                  });
+                },
+              ))),
+    ]));
+
     items.add(ConfigSection(children: [
       ConfigPageItem(
           label: Text('Enroll with Managed Nebula'),
-          labelWidth: 200,
+          labelWidth: 250,
           onPressed: () =>
               Utils.openPage(context, (context) => EnrollmentScreen(stream: widget.stream, allowCodeEntry: true)))
     ]));

lib/services/settings.dart

@@ -3,6 +3,10 @@ import 'dart:convert';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/scheduler.dart';
 import 'package:mobile_nebula/services/storage.dart';
+import 'package:sentry_flutter/sentry_flutter.dart';
+
+bool DEFAULT_LOG_WRAP = false;
+bool DEFAULT_TRACK_ERRORS = true;
 
 class Settings {
   final _storage = Storage();
@@ -30,13 +34,26 @@ class Settings {
   }
 
   bool get logWrap {
-    return _getBool('logWrap', false);
+    return _getBool('logWrap', DEFAULT_LOG_WRAP);
   }
 
   set logWrap(bool enabled) {
     _set('logWrap', enabled);
   }
 
+  bool get trackErrors {
+    return _getBool('trackErrors', DEFAULT_TRACK_ERRORS);
+  }
+
+  set trackErrors(bool enabled) {
+    _set('trackErrors', enabled);
+
+    // Side-effect: Disable Sentry immediately
+    if (!enabled) {
+      Sentry.close();
+    }
+  }
+
   String _getString(String key, String defaultValue) {
     final val = _settings[key];
     if (val is String) {

lib/services/storage.dart

@@ -42,7 +42,6 @@ class Storage {
       // Read the file
       return await file.readAsString();
     } catch (e) {
-      // If encountering an error, return 0
       return null;
     }
   }