# Unified Logging System

The TCP Dashboard project uses a unified logging system that provides consistent, centralized logging across all components with advanced conditional logging capabilities.

## Features

- **Component-specific directories**: Each component gets its own log directory
- **Date-based file rotation**: New log files created daily automatically
- **Unified format**: Consistent timestamp and message format across all logs
- **Thread-safe**: Safe for use in multi-threaded applications
- **Verbose console logging**: Configurable console output with proper log level handling
- **Automatic log cleanup**: Built-in functionality to remove old log files automatically
- **Error handling**: Graceful fallback to console logging if file logging fails
- **Conditional logging**: Components can operate with or without loggers
- **Error-only logging**: Option to log only error-level messages
- **Hierarchical logging**: Parent components can pass loggers to children
- **Logger inheritance**: Consistent logging across component hierarchies

## Conditional Logging System

The TCP Dashboard implements a sophisticated conditional logging system that allows components to work with or without loggers, providing maximum flexibility for different deployment scenarios.

### Key Concepts

1. **Optional Logging**: Components accept `logger=None` and function normally without logging
2. **Error-Only Mode**: Components can log only error-level messages with `log_errors_only=True`
3. **Logger Inheritance**: Parent components pass their logger to child components
4. **Hierarchical Structure**: Log files are organized by component hierarchy

### Usage Patterns

#### 1. No Logging
```python
from data.collector_manager import CollectorManager
from data.exchanges.okx.collector import OKXCollector

# Components work without any logging
manager = CollectorManager(logger=None)
collector = OKXCollector("BTC-USDT", logger=None)

# No log files created, no console output
# Components function normally without exceptions
```

#### 2. Normal Logging
```python
from utils.logger import get_logger
from data.collector_manager import CollectorManager

# Create logger for the manager
logger = get_logger('production_manager')

# Manager logs all activities
manager = CollectorManager(logger=logger)

# Child components inherit the logger
collector = manager.add_okx_collector("BTC-USDT")  # Uses manager's logger
```

#### 3. Error-Only Logging
```python
from utils.logger import get_logger
from data.exchanges.okx.collector import OKXCollector

# Create logger but only log errors
logger = get_logger('critical_only')

# Only error and critical messages are logged
collector = OKXCollector(
    "BTC-USDT", 
    logger=logger, 
    log_errors_only=True
)

# Debug, info, warning messages are suppressed
# Error and critical messages are always logged
```

#### 4. Hierarchical Logging
```python
from utils.logger import get_logger
from data.collector_manager import CollectorManager

# Top-level application logger
app_logger = get_logger('tcp_dashboard')

# Production manager with its own logger
prod_logger = get_logger('production_manager')
manager = CollectorManager(logger=prod_logger)

# Individual collectors with specific loggers
btc_logger = get_logger('btc_collector')
btc_collector = OKXCollector("BTC-USDT", logger=btc_logger)

eth_collector = OKXCollector("ETH-USDT", logger=None)  # No logging

# Results in organized log structure:
# logs/tcp_dashboard/
# logs/production_manager/
# logs/btc_collector/
# (no logs for ETH collector)
```

#### 5. Mixed Configuration
```python
from utils.logger import get_logger
from data.collector_manager import CollectorManager

# System logger for normal operations
system_logger = get_logger('system')

# Critical logger for error-only components
critical_logger = get_logger('critical_only')

manager = CollectorManager(logger=system_logger)

# Different logging strategies for different collectors
btc_collector = OKXCollector("BTC-USDT", logger=system_logger)  # Full logging
eth_collector = OKXCollector("ETH-USDT", logger=critical_logger, log_errors_only=True)  # Errors only
ada_collector = OKXCollector("ADA-USDT", logger=None)  # No logging

manager.add_collector(btc_collector)
manager.add_collector(eth_collector)
manager.add_collector(ada_collector)
```

### Implementation Details

#### Component Constructor Pattern
All major components follow this pattern:
```python
class ComponentExample:
    def __init__(self, logger=None, log_errors_only=False):
        self.logger = logger
        self.log_errors_only = log_errors_only
        
        # Conditional logging helpers
        self._log_debug = self._create_conditional_logger('debug')
        self._log_info = self._create_conditional_logger('info')
        self._log_warning = self._create_conditional_logger('warning')
        self._log_error = self._create_conditional_logger('error')
        self._log_critical = self._create_conditional_logger('critical')
    
    def _create_conditional_logger(self, level):
        """Create conditional logging function based on configuration."""
        if not self.logger:
            return lambda msg: None  # No-op if no logger
        
        log_func = getattr(self.logger, level)
        
        if level in ['debug', 'info', 'warning'] and self.log_errors_only:
            return lambda msg: None  # Suppress non-error messages
        
        return log_func  # Normal logging
```

#### Supported Components

The following components support conditional logging:

1. **BaseDataCollector** (`data/base_collector.py`)
   - Parameters: `logger=None, log_errors_only=False`
   - Conditional logging for all collector operations

2. **CollectorManager** (`data/collector_manager.py`)
   - Parameters: `logger=None, log_errors_only=False`
   - Manages multiple collectors with consistent logging

3. **OKXCollector** (`data/exchanges/okx/collector.py`)
   - Parameters: `logger=None, log_errors_only=False`
   - Exchange-specific data collection with conditional logging

4. **BaseDataValidator** (`data/common/validation.py`)
   - Parameters: `logger=None`
   - Data validation with optional logging

5. **OKXDataTransformer** (`data/exchanges/okx/data_processor.py`)
   - Parameters: `logger=None`
   - Data processing with conditional logging

### Best Practices for Conditional Logging

#### 1. Logger Inheritance
```python
# Parent component creates logger
parent_logger = get_logger('parent_system')
parent = ParentComponent(logger=parent_logger)

# Pass logger to children for consistent hierarchy
child1 = ChildComponent(logger=parent_logger)
child2 = ChildComponent(logger=parent_logger, log_errors_only=True)
child3 = ChildComponent(logger=None)  # No logging
```

#### 2. Environment-Based Configuration
```python
import os
from utils.logger import get_logger

def create_system_logger():
    """Create logger based on environment."""
    env = os.getenv('ENVIRONMENT', 'development')
    
    if env == 'production':
        return get_logger('production_system', log_level='INFO', verbose=False)
    elif env == 'testing':
        return None  # No logging during tests
    else:
        return get_logger('dev_system', log_level='DEBUG', verbose=True)

# Use in components
system_logger = create_system_logger()
manager = CollectorManager(logger=system_logger)
```

#### 3. Conditional Error-Only Mode
```python
def create_collector_with_logging_strategy(symbol, strategy='normal'):
    """Create collector with different logging strategies."""
    base_logger = get_logger(f'collector_{symbol.lower().replace("-", "_")}')
    
    if strategy == 'silent':
        return OKXCollector(symbol, logger=None)
    elif strategy == 'errors_only':
        return OKXCollector(symbol, logger=base_logger, log_errors_only=True)
    else:
        return OKXCollector(symbol, logger=base_logger)

# Usage
btc_collector = create_collector_with_logging_strategy('BTC-USDT', 'normal')
eth_collector = create_collector_with_logging_strategy('ETH-USDT', 'errors_only')
ada_collector = create_collector_with_logging_strategy('ADA-USDT', 'silent')
```

#### 4. Performance Optimization
```python
class OptimizedComponent:
    def __init__(self, logger=None, log_errors_only=False):
        self.logger = logger
        self.log_errors_only = log_errors_only
        
        # Pre-compute logging capabilities for performance
        self.can_log_debug = logger and not log_errors_only
        self.can_log_info = logger and not log_errors_only
        self.can_log_warning = logger and not log_errors_only
        self.can_log_error = logger is not None
        self.can_log_critical = logger is not None
    
    def process_data(self, data):
        if self.can_log_debug:
            self.logger.debug(f"Processing {len(data)} records")
        
        # ... processing logic ...
        
        if self.can_log_info:
            self.logger.info("Data processing completed")
```

### Migration Guide

#### From Standard Logging
```python
# Old approach
import logging
logger = logging.getLogger(__name__)

class OldComponent:
    def __init__(self):
        self.logger = logger

# New conditional approach
from utils.logger import get_logger

class NewComponent:
    def __init__(self, logger=None, log_errors_only=False):
        self.logger = logger
        self.log_errors_only = log_errors_only
        
        # Add conditional logging helpers
        self._setup_conditional_logging()
```

#### Gradual Adoption
1. **Phase 1**: Add optional logger parameters to new components
2. **Phase 2**: Update existing components to support conditional logging
3. **Phase 3**: Implement hierarchical logging structure
4. **Phase 4**: Add error-only logging mode

### Testing Conditional Logging

#### Test Script Example
```python
# test_conditional_logging.py
from utils.logger import get_logger
from data.collector_manager import CollectorManager
from data.exchanges.okx.collector import OKXCollector

def test_no_logging():
    """Test components work without loggers."""
    manager = CollectorManager(logger=None)
    collector = OKXCollector("BTC-USDT", logger=None)
    print("✓ No logging test passed")

def test_with_logging():
    """Test components work with loggers."""
    logger = get_logger('test_system')
    manager = CollectorManager(logger=logger)
    collector = OKXCollector("BTC-USDT", logger=logger)
    print("✓ With logging test passed")

def test_error_only():
    """Test error-only logging mode."""
    logger = get_logger('test_errors')
    collector = OKXCollector("BTC-USDT", logger=logger, log_errors_only=True)
    print("✓ Error-only logging test passed")

if __name__ == "__main__":
    test_no_logging()
    test_with_logging()
    test_error_only()
    print("✅ All conditional logging tests passed!")
```

## Log Format

All log messages follow this unified format:
```
[YYYY-MM-DD HH:MM:SS - LEVEL - message]
```

Example:
```
[2024-01-15 14:30:25 - INFO - Bot started successfully]
[2024-01-15 14:30:26 - ERROR - Connection failed: timeout]
```

## File Organization

Logs are organized in a hierarchical structure:
```
logs/
├── app/
│   ├── 2024-01-15.txt
│   └── 2024-01-16.txt
├── bot_manager/
│   ├── 2024-01-15.txt
│   └── 2024-01-16.txt
├── data_collector/
│   └── 2024-01-15.txt
└── strategies/
    └── 2024-01-15.txt
```

## Basic Usage

### Import and Initialize

```python
from utils.logger import get_logger

# Basic usage - gets logger with default settings
logger = get_logger('bot_manager')

# With verbose console output
logger = get_logger('bot_manager', verbose=True)

# With custom cleanup settings
logger = get_logger('bot_manager', clean_old_logs=True, max_log_files=7)

# All parameters
logger = get_logger(
    component_name='bot_manager',
    log_level='DEBUG',
    verbose=True,
    clean_old_logs=True,
    max_log_files=14
)
```

### Log Messages

```python
# Different log levels
logger.debug("Detailed debugging information")
logger.info("General information about program execution")
logger.warning("Something unexpected happened")
logger.error("An error occurred", exc_info=True)  # Include stack trace
logger.critical("A critical error occurred")
```

### Complete Example

```python
from utils.logger import get_logger

class BotManager:
    def __init__(self):
        # Initialize with verbose output and keep only 7 days of logs
        self.logger = get_logger('bot_manager', verbose=True, max_log_files=7)
        self.logger.info("BotManager initialized")
    
    def start_bot(self, bot_id: str):
        try:
            self.logger.info(f"Starting bot {bot_id}")
            # Bot startup logic here
            self.logger.info(f"Bot {bot_id} started successfully")
        except Exception as e:
            self.logger.error(f"Failed to start bot {bot_id}: {e}", exc_info=True)
            raise
    
    def stop_bot(self, bot_id: str):
        self.logger.info(f"Stopping bot {bot_id}")
        # Bot shutdown logic here
        self.logger.info(f"Bot {bot_id} stopped")
```

## Configuration

### Logger Parameters

The `get_logger()` function accepts several parameters for customization:

```python
get_logger(
    component_name: str,           # Required: component name
    log_level: str = "INFO",       # Log level: DEBUG, INFO, WARNING, ERROR, CRITICAL
    verbose: Optional[bool] = None, # Console logging: True, False, or None (use env)
    clean_old_logs: bool = True,   # Auto-cleanup old logs
    max_log_files: int = 30        # Max number of log files to keep
)
```

### Log Levels

Set the log level when getting a logger:
```python
# Available levels: DEBUG, INFO, WARNING, ERROR, CRITICAL
logger = get_logger('component_name', 'DEBUG')  # Show all messages
logger = get_logger('component_name', 'ERROR')  # Show only errors and critical
```

### Verbose Console Logging

Control console output with the `verbose` parameter:

```python
# Explicit verbose settings
logger = get_logger('bot_manager', verbose=True)   # Always show console logs
logger = get_logger('bot_manager', verbose=False)  # Never show console logs

# Use environment variable (default behavior)
logger = get_logger('bot_manager', verbose=None)   # Uses VERBOSE_LOGGING from .env
```

Environment variables for console logging:
```bash
# In .env file or environment
VERBOSE_LOGGING=true     # Enable verbose console logging
LOG_TO_CONSOLE=true      # Alternative environment variable (backward compatibility)
```

Console output respects log levels:
- **DEBUG level**: Shows all messages (DEBUG, INFO, WARNING, ERROR, CRITICAL)
- **INFO level**: Shows INFO and above (INFO, WARNING, ERROR, CRITICAL)
- **WARNING level**: Shows WARNING and above (WARNING, ERROR, CRITICAL)
- **ERROR level**: Shows ERROR and above (ERROR, CRITICAL)
- **CRITICAL level**: Shows only CRITICAL messages

### Automatic Log Cleanup

Control automatic cleanup of old log files:

```python
# Enable automatic cleanup (default)
logger = get_logger('bot_manager', clean_old_logs=True, max_log_files=7)

# Disable automatic cleanup
logger = get_logger('bot_manager', clean_old_logs=False)

# Custom retention (keep 14 most recent log files)
logger = get_logger('bot_manager', max_log_files=14)
```

**How automatic cleanup works:**
- Triggered every time a new log file is created (date change)
- Keeps only the most recent `max_log_files` files
- Deletes older files automatically
- Based on file modification time, not filename

## Advanced Features

### Manual Log Cleanup

Remove old log files manually based on age:
```python
from utils.logger import cleanup_old_logs

# Remove logs older than 30 days for a specific component
cleanup_old_logs('bot_manager', days_to_keep=30)

# Or clean up logs for multiple components
for component in ['bot_manager', 'data_collector', 'strategies']:
    cleanup_old_logs(component, days_to_keep=7)
```

### Error Handling with Context

```python
try:
    risky_operation()
except Exception as e:
    logger.error(f"Operation failed: {e}", exc_info=True)
    # exc_info=True includes the full stack trace
```

### Structured Logging

For complex data, use structured messages:
```python
# Good: Structured information
logger.info(f"Trade executed: symbol={symbol}, price={price}, quantity={quantity}")

# Even better: JSON-like structure for parsing
logger.info(f"Trade executed", extra={
    'symbol': symbol,
    'price': price,
    'quantity': quantity,
    'timestamp': datetime.now().isoformat()
})
```

## Configuration Examples

### Development Environment
```python
# Verbose logging with frequent cleanup
logger = get_logger(
    'bot_manager',
    log_level='DEBUG',
    verbose=True,
    max_log_files=3  # Keep only 3 days of logs
)
```

### Production Environment
```python
# Minimal console output with longer retention
logger = get_logger(
    'bot_manager',
    log_level='INFO',
    verbose=False,
    max_log_files=30  # Keep 30 days of logs
)
```

### Testing Environment
```python
# Disable cleanup for testing
logger = get_logger(
    'test_component',
    log_level='DEBUG',
    verbose=True,
    clean_old_logs=False  # Don't delete logs during tests
)
```

## Environment Variables

Create a `.env` file to control default logging behavior:

```bash
# Enable verbose console logging globally
VERBOSE_LOGGING=true

# Alternative (backward compatibility)
LOG_TO_CONSOLE=true
```

## Best Practices

### 1. Component Naming

Use descriptive, consistent component names:
- `bot_manager` - for bot lifecycle management
- `data_collector` - for market data collection
- `strategies` - for trading strategies
- `backtesting` - for backtesting engine
- `dashboard` - for web dashboard

### 2. Log Level Guidelines

- **DEBUG**: Detailed diagnostic information, typically only of interest when diagnosing problems
- **INFO**: General information about program execution
- **WARNING**: Something unexpected happened, but the program is still working
- **ERROR**: A serious problem occurred, the program couldn't perform a function
- **CRITICAL**: A serious error occurred, the program may not be able to continue

### 3. Verbose Logging Guidelines

```python
# Development: Use verbose logging with DEBUG level
dev_logger = get_logger('component', 'DEBUG', verbose=True, max_log_files=3)

# Production: Use INFO level with no console output
prod_logger = get_logger('component', 'INFO', verbose=False, max_log_files=30)

# Testing: Disable cleanup to preserve test logs
test_logger = get_logger('test_component', 'DEBUG', verbose=True, clean_old_logs=False)
```

### 4. Log Retention Guidelines

```python
# High-frequency components (data collectors): shorter retention
data_logger = get_logger('data_collector', max_log_files=7)

# Important components (bot managers): longer retention
bot_logger = get_logger('bot_manager', max_log_files=30)

# Development: very short retention
dev_logger = get_logger('dev_component', max_log_files=3)
```

### 5. Message Content

```python
# Good: Descriptive and actionable
logger.error("Failed to connect to OKX API: timeout after 30s")

# Bad: Vague and unhelpful
logger.error("Error occurred")

# Good: Include relevant context
logger.info(f"Bot {bot_id} executed trade: {symbol} {side} {quantity}@{price}")

# Good: Include duration for performance monitoring
start_time = time.time()
# ... do work ...
duration = time.time() - start_time
logger.info(f"Data aggregation completed in {duration:.2f}s")
```

### 6. Exception Handling

```python
try:
    execute_trade(symbol, quantity, price)
    logger.info(f"Trade executed successfully: {symbol}")
except APIError as e:
    logger.error(f"API error during trade execution: {e}", exc_info=True)
    raise
except ValidationError as e:
    logger.warning(f"Trade validation failed: {e}")
    return False
except Exception as e:
    logger.critical(f"Unexpected error during trade execution: {e}", exc_info=True)
    raise
```

### 7. Performance Considerations

```python
# Good: Efficient string formatting
logger.debug(f"Processing {len(data)} records")

# Avoid: Expensive operations in log messages unless necessary
# logger.debug(f"Data: {expensive_serialization(data)}")  # Only if needed

# Better: Check log level first for expensive operations
if logger.isEnabledFor(logging.DEBUG):
    logger.debug(f"Data: {expensive_serialization(data)}")
```

## Integration with Existing Code

The logging system is designed to be gradually adopted:

1. **Start with new modules**: Use the unified logger in new code
2. **Replace existing logging**: Gradually migrate existing logging to the unified system
3. **No breaking changes**: Existing code continues to work

### Migration Example

```python
# Old logging (if any existed)
import logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# New unified logging
from utils.logger import get_logger
logger = get_logger('component_name', verbose=True)
```

## Testing

Run a simple test to verify the logging system:
```bash
python -c "from utils.logger import get_logger; logger = get_logger('test', verbose=True); logger.info('Test message'); print('Check logs/test/ directory')"
```

## Maintenance

### Automatic Cleanup Benefits

The automatic cleanup feature provides several benefits:
- **Disk space management**: Prevents log directories from growing indefinitely
- **Performance**: Fewer files to scan in log directories
- **Maintenance-free**: No need for external cron jobs or scripts
- **Component-specific**: Each component can have different retention policies

### Manual Cleanup for Special Cases

For cases requiring age-based cleanup instead of count-based:
```python
# cleanup_logs.py
from utils.logger import cleanup_old_logs

components = ['bot_manager', 'data_collector', 'strategies', 'dashboard']
for component in components:
    cleanup_old_logs(component, days_to_keep=30)
```

### Monitoring Disk Usage

Monitor the `logs/` directory size and adjust retention policies as needed:
```bash
# Check log directory size
du -sh logs/

# Find large log files
find logs/ -name "*.txt" -size +10M

# Count log files per component
find logs/ -name "*.txt" | cut -d'/' -f2 | sort | uniq -c
```

## Troubleshooting

### Common Issues

1. **Permission errors**: Ensure the application has write permissions to the project directory
2. **Disk space**: Monitor disk usage and adjust log retention with `max_log_files`
3. **Threading issues**: The logger is thread-safe, but check for application-level concurrency issues
4. **Too many console messages**: Adjust `verbose` parameter or log levels

### Debug Mode

Enable debug logging to troubleshoot issues:
```python
logger = get_logger('component_name', 'DEBUG', verbose=True)
```

### Console Output Issues

```python
# Force console output regardless of environment
logger = get_logger('component_name', verbose=True)

# Check environment variables
import os
print(f"VERBOSE_LOGGING: {os.getenv('VERBOSE_LOGGING')}")
print(f"LOG_TO_CONSOLE: {os.getenv('LOG_TO_CONSOLE')}")
```

### Fallback Logging

If file logging fails, the system automatically falls back to console logging with a warning message.

## New Features Summary

### Verbose Parameter
- Controls console logging output
- Respects log levels (DEBUG shows all, ERROR shows only errors)
- Uses environment variables as default (`VERBOSE_LOGGING` or `LOG_TO_CONSOLE`)
- Can be explicitly set to `True`/`False` to override environment

### Automatic Cleanup
- Enabled by default (`clean_old_logs=True`)
- Triggered when new log files are created (date changes)
- Keeps most recent `max_log_files` files (default: 30)
- Component-specific retention policies
- Non-blocking operation with error handling