log_warning() Function¶

Silent warning logging system that maintains clean console output while capturing detailed warning information.

Overview¶

Core logging function that writes warnings to transfer_warnings.log file instead of console output. Ensures clean user interface while providing comprehensive warning information for troubleshooting and monitoring.

Function Signature¶

def log_warning(message: str):
    """Log warning message to transfer_warnings.log file"""
    try:
        timestamp = datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")
        with open("transfer_warnings.log", "a", encoding="utf-8") as f:
            f.write(f"[{timestamp}] {message}\n")
    except Exception:
        # Silently ignore logging failures to avoid disrupting transfer
        pass

Parameters¶

Return Value¶

• Type: None
• Description: Function writes to log file or silently ignores failures

Warning Categories¶

File Access Warnings¶

log_warning(f"Permission denied accessing {current_path}")
log_warning(f"Skipping {path} (not a regular file or directory)")

File Operation Warnings¶

log_warning(f"Failed to write to {self.part_file}: {e}")
log_warning(f"Failed to complete file {self.filename}: {e}")
log_warning(f"Could not locate final file for {writer.filename}")

Resource Monitoring Warnings¶

log_warning(f"High FD usage: {current}/{limit} ({percent}%) for {file_count} files")
log_warning(f"Consider transferring fewer files or increasing limits")

Lock File System Warnings¶

log_warning(f"Source file changed: {filename} (will be retransferred)")
log_warning(f"Invalid lock file structure, ignoring: {lock_file_path}")
log_warning(f"Stale lock file found (age: {age}), ignoring")

Log File Format¶

File Location¶

• Filename: transfer_warnings.log
• Location: Current working directory
• Encoding: UTF-8

Entry Format¶

[YYYY-MM-DD HH:MM:SS] Warning message text
[2024-01-01 12:34:56] Permission denied accessing /protected/file.txt
[2024-01-01 12:35:12] Failed to write to document.pdf.part: No space left on device
[2024-01-01 12:35:45] Source file changed: config.json (will be retransferred)

Warning Logging Workflow¶

graph TD
    warning_event(["Warning condition<br/>detected"])

    log_call["log_warning(message)<br/>called"]

    generate_timestamp["Generate timestamp:<br/>YYYY-MM-DD HH:MM:SS"]

    open_file["Open transfer_warnings.log<br/>in append mode"]
    format_entry["Format entry:<br/>[timestamp] message"]
    write_entry["Write entry to file<br/>with newline"]

    file_error{"File write error?"}
    silent_ignore["Silently ignore error<br/>(don't disrupt transfer)"]

    console_clean["Console output<br/>remains clean"]

    continue_transfer(["Transfer continues<br/>normally"])

    warning_event --> log_call
    log_call --> generate_timestamp
    generate_timestamp --> open_file
    open_file --> format_entry
    format_entry --> write_entry
    write_entry --> file_error
    file_error -->|error| silent_ignore
    file_error -->|success| console_clean
    silent_ignore --> continue_transfer
    console_clean --> continue_transfer

Design Principles¶

Silent Operation¶

• No Console Output: Warnings never appear on console
• Clean Interface: User sees only essential transfer information
• Non-Disruptive: Logging failures don't interrupt transfers

Comprehensive Logging¶

• All Warning Types: File, resource, lock, and operation warnings
• Detailed Context: Includes relevant file paths, error details, and system information
• Timestamp Precision: Second-level accuracy for debugging

Robust Error Handling¶

• Graceful Degradation: Logging failures are silently ignored
• Transfer Priority: Never let logging issues affect file transfer
• Exception Safety: Broad exception catching prevents crashes

Integration Points¶

File Operations¶

# Replace console warnings with file logging
# Old: print(f"Warning: Permission denied accessing {path}")
# New: log_warning(f"Permission denied accessing {path}")

FileWriter Class¶

• Write operation failures logged instead of printed
• File completion issues logged for debugging
• Part file management warnings captured

TransferLockManager¶

• Source file change detection warnings
• Lock file validation issues
• Stale lock cleanup notifications

ResourceMonitor¶

• File descriptor usage warnings
• System resource limit approaches
• Performance optimization suggestions

User Experience¶

Console Output Remains Clean¶

# What user sees (clean)
Connecting to sender... Authentication successful
Resuming transfer: 50 completed, 3 partial, 2 fresh files
Receiving 55 file(s) (1234567 bytes total)
Progress: 100.0% (1.5 MB/s)
Transfer complete!

# Warnings are silently logged to file

Warning Log Available for Troubleshooting¶

# User can check warnings if needed
$ cat transfer_warnings.log
[2024-01-01 12:34:56] Permission denied accessing /protected/config
[2024-01-01 12:35:12] Source file changed: data.json (will be retransferred)
[2024-01-01 12:35:45] High FD usage: 3200/4096 (78%) for 28712 files

Monitoring and Analysis¶

Log Analysis¶

• Pattern Detection: Identify recurring permission issues
• Performance Insights: Track resource usage patterns
• Transfer Diagnostics: Debug intermittent transfer issues

Operational Benefits¶

• Clean User Experience: No warning spam on console
• Complete Audit Trail: All warnings preserved for analysis
• System Health Monitoring: Resource and file system insights

Error Recovery Guidance¶

Common Warning Patterns¶

1. Permission Issues: Check file/directory permissions
2. Disk Space: Monitor available storage during transfers
3. Resource Limits: Adjust system limits for large transfers
4. File Changes: Source file modifications during transfer

Log File Management¶

• Rotation: Consider log rotation for long-running systems
• Cleanup: Remove old warning logs periodically
• Monitoring: Include in system monitoring for operational insights