Architecture#

Gold Digger's architecture and design decisions.

High-Level Architecture#

Core Components#

CLI Layer (main.rs, cli.rs)#

• Argument parsing with clap
• Environment variable fallback
• Configuration validation

Database Layer (lib.rs)#

• MySQL connection management
• Query execution
• Result set processing
• Delegates value conversion to TypeTransformer

Type Conversion (type_transformer.rs)#

• Canonical hub for safe MySQL value conversion
• Panic-free conversion of mysql::Value to String and serde_json::Value
• Key methods: value_to_string, value_to_json, row_to_strings, row_to_json
• Safety guarantees: NULL handling, invalid UTF-8 hex encoding, special float handling (NaN, Infinity), date/time validation
• Exported as public API via lib.rs

Output Layer (csv.rs, json.rs, tab.rs)#

• Format-specific serialization
• Consistent interface design
• Type-safe conversions

Design Principles#

Security First#

• Automatic credential redaction
• TLS/SSL by default
• Input validation and sanitization

Type Safety#

• Rust's ownership system prevents memory errors
• Explicit NULL handling
• Safe type conversions via TypeTransformer
• Comprehensive snapshot testing for conversion edge cases

Performance#

• Connection pooling
• Efficient serialization
• Minimal memory allocations

Key Design Decisions#

Memory Model#

• Current: Fully materialized results
• Rationale: Simplicity and reliability
• Future: Streaming support for large datasets

Error Handling#

• Pattern: anyhow::Result<T> throughout
• Benefits: Rich error context and propagation
• Trade-offs: Slightly larger binary size

Configuration Precedence#

• Order: CLI flags > Environment variables
• Rationale: Explicit overrides implicit
• Benefits: Predictable behavior in automation

Module Dependencies#

Future Architecture#

Planned Improvements#

• Streaming result processing
• Plugin system for custom formats
• Configuration file support
• Async/await for better concurrency