Python Server Logs

Overview

Views logs from Flask servers (local or remote) to monitor activity, debug issues, and check server status. Supports real-time streaming and historical log viewing.

When to Use

Invoke this skill when the user:

• Asks to "see server logs"
• Wants to "check what the server is doing"
• Says "view logs" or "monitor server"
• Mentions debugging server issues
• Wants to see recent server activity

Prerequisites

Local server:

• Server running in background mode (creates server.log)
• In server directory with log file

Remote server:

• SSH access configured
• SSH config alias set up (microserver)
• Remote server running

Instructions

View Local Server Logs

Real-time streaming (follows log as it grows):

cd path/to/server/imp/py
tail -f server.log

Last 20 lines:

tail -20 server.log

Last 50 lines:

tail -50 server.log

All logs:

cat server.log

Search logs:

grep "ERROR" server.log
grep "api/ping" server.log
grep "POST" server.log

View Remote Server Logs

Real-time streaming:

ssh microserver@185.96.221.52 "tail -f ~/firefly-server/server.log"

Last 20 lines:

ssh microserver@185.96.221.52 "tail -20 ~/firefly-server/server.log"

Search remote logs:

ssh microserver@185.96.221.52 "grep 'ERROR' ~/firefly-server/server.log"

What to Tell User

Local logs:

• Show command to view logs
• Mention Ctrl+C to stop streaming
• Indicate log file location
• Suggest useful search patterns

Remote logs:

• Same as local, but via SSH
• Mention network connection required
• Log format is identical

Log Format

Flask logs typically show:

127.0.0.1 - - [05/Oct/2024 18:15:23] "GET /api/ping HTTP/1.1" 200 -
127.0.0.1 - - [05/Oct/2024 18:15:24] "POST /api/posts HTTP/1.1" 200 -

Format:

• IP address: Client making request
• Timestamp: When request occurred
• Method: GET, POST, etc.
• Path: API endpoint
• Status: HTTP response code (200=OK, 500=error, etc.)

Common Log Patterns

Successful requests:

grep "200" server.log

Errors:

grep -E "(ERROR|500|404)" server.log

Specific endpoint:

grep "/api/ping" server.log

Recent activity:

tail -20 server.log

POST requests only:

grep "POST" server.log

Integration with Claude Code

Claude can read logs directly:

# Last 20 lines
tail -20 server.log

# Search for specific issue
grep "ERROR" server.log

This enables Claude to:

• Debug server issues
• Verify requests are reaching server
• Check for errors or warnings
• Monitor API usage patterns

Troubleshooting

"No such file or directory":

• Log file doesn't exist yet
• Server wasn't started in background mode
• Check: ls -la server.log
• Start server with start.sh to create logs

Logs not updating:

• Server may be running in foreground (logs to terminal)
• Check if process is running: lsof -ti:8080
• Verify server.log is the active log file

Too much output:

• Use tail instead of cat for large logs
• Filter with grep for specific patterns
• Consider log rotation for production

Can't access remote logs:

• Check SSH connection: ssh microserver@185.96.221.52 "ls"
• Verify path: ~/firefly-server/server.log
• Check permissions on remote log file

Log Levels

Flask can log at different levels:

• DEBUG: Detailed information for diagnosing problems
• INFO: General informational messages
• WARNING: Warning messages for potential issues
• ERROR: Error messages for serious problems
• CRITICAL: Critical errors causing server failure

Flask development server logs most requests at INFO level.

Clearing Logs

Local:

# Clear log file
> server.log
# Or delete and recreate
rm server.log
touch server.log

Remote:

ssh microserver@185.96.221.52 "> ~/firefly-server/server.log"

This is useful before testing to see only new logs.

Advanced Usage

Follow logs and filter:

tail -f server.log | grep "ERROR"

Count requests per endpoint:

grep -o "/api/[a-z]*" server.log | sort | uniq -c

Show only errors:

grep -E "ERROR|500" server.log

Last hour of logs (if timestamps in log):

# Depends on log format
grep "$(date +%H:)" server.log

Foreground vs Background Logging

Foreground server (python3 app.py):

• Logs to terminal (stdout)
• No server.log file
• See logs in terminal directly
• Use py-server-logs for background servers only

Background server (./start.sh):

• Logs to server.log
• Terminal output redirected
• Use tail/grep to view
• This skill is designed for this mode

Remote Server Path

For Firefly server specifically:

• Path: ~/firefly-server/server.log
• Host: microserver@185.96.221.52
• Via SSH: ssh microserver@185.96.221.52

Stopping Log Stream

When using tail -f:

• Press Ctrl+C to stop streaming
• Terminal returns to prompt
• Log file continues to grow

Log Rotation

For production servers, implement log rotation:

• Prevents log files from growing too large
• Archives old logs
• Can use logrotate utility on Linux/macOS

For development, manual clearing is sufficient.

Notes

• Local and remote logs have identical format
• Logs persist across server restarts
• Log file grows continuously (monitor size)
• Background mode required for log file
• Real-time streaming with tail -f is most useful for active debugging