앱 성공을 위한 필수 요소: 장애 모니터링 (opens in new tab)
Effective mobile app management requires proactive outage monitoring to prevent user churn caused by failures in critical flows like registration or payment. Relying on user reports is often too late, so developers must implement systematic event collection and real-time dashboards to identify issues the moment they arise. By integrating tools like Sentry or Firebase, teams can maintain high quality through immediate response and detailed performance analysis. ### Implementing Sentry in Flutter * **Dependency and Initialization**: Integration begins by adding `sentry_flutter` and `sentry_dio` to the project. The initialization process involves setting the Data Source Name (DSN), environment tags (e.g., production vs. staging), and release versions to ensure logs are correctly categorized. * **Performance and Privacy**: Developers should configure `tracesSampleRate` and `profilesSampleRate` to balance monitoring depth with costs. Additionally, the `beforeSend` callback allows for masking sensitive user data like authorization headers or IP addresses before they are transmitted. * **Contextual Tracking**: To aid debugging, the system captures user IDs via `Sentry.configureScope` and tracks user movement using `SentryNavigatorObserver`. Utilizing `SentryInterceptor` with the Dio library allows for automatic tracking of HTTP request performance and API bottlenecks. ### Strategic Log Level Design * **Debug and Info**: Debug logs remain local to the terminal to save resources. Info logs are reserved for significant user actions that change data, such as successful sign-ups or purchases, while high-frequency read actions like "viewing a product list" are excluded to reduce noise and costs. * **Warning**: This level tracks external system failures, such as failed API calls or push notification losses. To prevent "alert fatigue," client-side network issues (e.g., timeouts or offline status) are ignored, and alerts are triggered only when specific thresholds are met, such as 100 failures within 10 minutes. * **Error**: Error logs represent internal logic failures that bypass defensive coding, such as null object errors, parsing failures, or unreachable code branches. These require immediate notification to the development team to facilitate rapid hotfixes. * **Fatal**: This level is dedicated to application crashes and unhandled exceptions. When configured at the app's entry point, the system automatically captures these critical failures to provide a comprehensive "crash-free users" metric. ### Creating Effective Dashboards * **Naming Conventions**: Logs should follow a strict structure, using tags for modules and event names (e.g., `[API] [postLogin] success`). This consistency allows for granular querying and clearer visualization on monitoring dashboards. * **Data Enrichment**: Using the `extra` field in log events provides vital context for troubleshooting, such as including the specific endpoint, request body, and response status code for a failed transaction. * **Actionable Metrics**: Effective monitoring focuses on key performance indicators like API error rates and the failure percentage of core business events (login, registration, payment) rather than just raw crash counts. A robust monitoring strategy shifts the focus from simple crash reporting to comprehensive service health. By standardizing log levels and automating event collection, development teams can distinguish between transient network blips and critical logic errors, ensuring they spend their time fixing high-impact issues.