Mining/AUDIT-MEMORY.md

Memory and Resource Management Audit

This audit examines the application's memory and resource management based on a review of the codebase, with a focus on pkg/mining/manager.go, pkg/mining/service.go, and pkg/database/database.go.

1. Goroutine Leak Analysis

The application uses several long-running goroutines for background tasks. Overall, goroutine lifecycle management is robust, but there are minor areas for improvement.

Findings:

• Stats Collection (manager.go): The startStatsCollection goroutine runs in a for loop with a time.Ticker. It reliably terminates when the stopChan is closed during Manager.Stop().
• Database Cleanup (manager.go): The startDBCleanup goroutine also uses a time.Ticker and correctly listens for the stopChan signal, ensuring it exits cleanly.
• WebSocket Event Hub (service.go): The EventHub.Run method is launched as a goroutine and manages client connections. It terminates when its internal quit channel is closed, which is triggered by the EventHub.Stop() method.

Recommendations:

• No major issues found. The use of stopChan and sync.WaitGroup in Manager provides a solid foundation for graceful shutdowns.

2. Memory Leak Analysis

The primary areas of concern for memory leaks are in-memory data structures that could grow indefinitely.

Findings:

• Manager.miners Map: The miners map in the Manager struct stores active miner processes. Entries are added in StartMiner and removed in StopMiner and UninstallMiner. If a miner process were to crash or become unresponsive without StopMiner being called, its entry would persist in the map, causing a minor memory leak.
• In-Memory Hashrate History: Each miner maintains an in-memory HashrateHistory. The ReduceHashrateHistory method is called periodically to trim this data, preventing unbounded growth. This is a good practice.
• Request Body Size Limit: The service.go file correctly implements a 1MB request body size limit, which helps prevent memory exhaustion from large API requests.

Recommendations:

• Implement a health check for miners. A periodic health check could detect unresponsive miner processes and trigger their removal from the miners map, preventing memory leaks from orphaned entries.

3. Database Resource Management

The application uses an SQLite database for persisting historical data.

Findings:

• Connection Pooling: The database.go file configures the connection pool with SetMaxOpenConns(1). This is appropriate for SQLite's single-writer model and prevents connection-related issues.
• hashrate_history Cleanup: The Cleanup function in database.go correctly removes old records from the hashrate_history table based on the configured retention period.
• miner_sessions Table: The miner_sessions table tracks miner uptime but has no corresponding cleanup mechanism. This table will grow indefinitely, leading to a gradual increase in database size and a potential performance degradation over time.

Recommendations:

• Add a cleanup mechanism for miner_sessions. Extend the Cleanup function to also remove old records from the miner_sessions table based on the retention period.

4. File Handle and Process Management

The application manages external miner processes, which requires careful handling of file descriptors and process handles.

Findings:

• Process Lifecycle: The Stop method on miner implementations (xmrig.go, ttminer.go) is responsible for terminating the exec.Cmd process. This appears to be handled correctly.
• I/O Pipes: The miner's stdout, stderr, and stdin pipes are created and managed. The code does not show any obvious leaks of these file handles.

Recommendations:

• No major issues found. The process management logic appears to be sound.

5. Network Connection Handling

The application's API server and WebSocket endpoint are critical areas for resource management.

Findings:

• HTTP Server Timeouts: The service.go file correctly configures ReadTimeout, WriteTimeout, and IdleTimeout for the HTTP server, which is a best practice for preventing slow client attacks and connection exhaustion.
• WebSocket Connections: The wsUpgrader has a CheckOrigin function that restricts connections to localhost origins, providing a layer of security. The EventHub manages the lifecycle of WebSocket connections.

Recommendations:

• No major issues found. The network connection handling is well-configured.