Mining/AUDIT-ERROR-HANDLING.md

Error Handling and Logging Audit

1. Error Handling

Exception Handling & Error Recovery

• Graceful Degradation: The application demonstrates graceful degradation in pkg/mining/service.go, where the NewService function continues to operate with a minimal in-memory profile manager if the primary one fails to initialize. This ensures core functionality remains available.
• Inconsistent Top-Level Handling: Error handling at the application's entry points is inconsistent.
  • In cmd/desktop/mining-desktop/main.go, errors from fs.Sub and app.Run are handled with log.Fatal, which abruptly terminates the application without using the project's structured logger.
  • In cmd/mining/main.go, errors from cmd.Execute are printed to stderr with fmt.Fprintf, and the application exits with a status code of 1. This is a standard CLI pattern but bypasses the custom logging framework.
• No Retry or Circuit Breaker Patterns: The codebase does not currently implement explicit retry logic with backoff or circuit breaker patterns for handling failures in external dependencies or services. However, the API error response includes a Retryable field, which correctly signals to clients when a retry is appropriate (e.g., for 503 Service Unavailable).

User-Facing & API Errors

• Standard API Error Response: The API service (pkg/mining/service.go) excels at providing consistent, user-friendly error responses.
  • It uses a well-defined APIError struct that includes a machine-readable code, a human-readable message, and an optional suggestion to guide the user.
  • The respondWithError and respondWithMiningError functions centralize error response logic, ensuring all API errors follow a consistent format.
• Appropriate HTTP Status Codes: The API correctly maps application errors to standard HTTP status codes (e.g., 404 Not Found for missing miners, 400 Bad Request for invalid input, 500 Internal Server Error for server-side issues).
• Controlled Information Leakage: The sanitizeErrorDetails function prevents the leakage of sensitive internal error details in production environments (GIN_MODE=release), enhancing security. Debug information is only exposed when DEBUG_ERRors is enabled.

2. Logging

Log Content and Quality

• Custom Structured Logger: The project includes a custom logger in pkg/logging/logger.go that supports standard log levels (Debug, Info, Warn, Error) and allows for structured logging by attaching key-value fields.
• No JSON Output: The logger's output is a custom string format (timestamp [LEVEL] [component] message | key=value), not structured JSON. This makes logs less machine-readable and harder to parse, filter, and analyze with modern log management tools.
• Good Context in Error Logs: The existing usage of logging.Error throughout the pkg/mining module is effective, consistently including relevant context (e.g., miner, panic, error) as structured fields.
• Request Correlation: The API service (pkg/mining/service.go) implements a requestIDMiddleware that assigns a unique X-Request-ID to each request, which is then included in logs. This is excellent practice for tracing and debugging.

What is Not Logged

• No Sensitive Data: Based on a review of logging.Error usage, the application appears to correctly avoid logging sensitive information such as passwords, tokens, or personally identifiable information (PII).

Inconsistencies

• Inconsistent Adoption: The custom logger is not used consistently across the project. The main packages for both the desktop and CLI applications (cmd/desktop/mining-desktop/main.go and cmd/mining/main.go) use the standard log and fmt packages for error handling, bypassing the structured logger.
• No Centralized Configuration: There is no centralized logger initialization in main or root.go. The global logger is used with its default configuration (Info level, stderr output), and there is no clear mechanism for configuring the log level or output via command-line flags or a configuration file.

3. Recommendations

1. Adopt Structured JSON Logging: Modify the logger in pkg/logging/logger.go to output logs in JSON format. This will significantly improve the logs' utility by making them machine-readable and compatible with log analysis platforms like Splunk, Datadog, or the ELK stack.

2. Centralize Logger Configuration:

   • In cmd/mining/cmd/root.go, add persistent flags for --log-level and --log-format (e.g., text, json).
   • In an init function, parse these flags and configure the global logging.Logger instance accordingly.
   • Do the same for the desktop application in cmd/desktop/mining-desktop/main.go, potentially reading from a configuration file or environment variables.

3. Standardize on the Global Logger:

   • Replace all instances of log.Fatal in cmd/desktop/mining-desktop/main.go with logging.Error followed by os.Exit(1).
   • Replace fmt.Fprintf(os.Stderr, ...) in cmd/mining/main.go with a call to logging.Error.

4. Enrich API Error Logs: In pkg/mining/service.go, enhance the respondWithError function to log every API error it handles using the structured logger. This will ensure that all error conditions, including client-side errors like bad requests, are recorded for monitoring and analysis. Include the request_id in every log entry.

5. Review Log Levels: Conduct a codebase-wide review of log levels. Ensure that Debug is used for verbose, development-time information, Info for significant operational events, Warn for recoverable issues, and Error for critical, action-required failures.