Handles formatting and writing ETS dump data to structured log files.

Overview

SickGrandma.Logger is responsible for taking raw ETS data and metadata from ETSDumper and converting it into human-readable, well-formatted log files. It manages file system operations, directory creation, and output formatting.

File Organization

All log files are created in a standardized directory structure:

~/.sick_grandma/
└── logs/
    ├── ets_dump_2024-01-15T10-30-45-123456Z.log      # Full dumps
    ├── ets_table_my_cache_2024-01-15T10-30-45-123456Z.log  # Single table
    └── ets_table_8207_2024-01-15T10-30-45-123456Z.log      # Table by ID

Log Format

Each log file contains:

• Header: Timestamp, operation type, summary information
• Table Metadata: ID, name, type, size, memory usage, ownership
• Data Section: Formatted table contents (limited to prevent huge files)
• Footer: End markers and additional metadata

Data Formatting Features

• Truncation: Large tables limited to first 100 entries
• Pretty Printing: Elixir terms formatted with proper indentation
• Error Handling: Clear error messages for inaccessible data
• Metadata: Rich context about each table's properties

File Safety

• Atomic Writes: Files written completely or not at all
• Unique Names: Timestamp-based naming prevents conflicts
• Directory Creation: Automatically creates required directories
• Error Recovery: Detailed error reporting for file system issues

Configuration

The module uses compile-time constants for directory structure:

• @log_dir_name - Base directory name (.sick_grandma)
• @logs_subdir - Subdirectory for log files (logs)

Performance Considerations

• Memory Efficient: Streams large data sets when possible
• I/O Optimization: Batches file operations
• Size Limits: Prevents runaway log file sizes
• Concurrent Safe: Multiple processes can write simultaneously

Error Handling

File system errors are wrapped with context:

• {:mkdir_failed, reason} - Directory creation failed
• {:write_failed, reason} - File writing failed

See Also

• SickGrandma.ETSDumper - Data source for logging operations
• SickGrandma - Main API that coordinates dumping and logging