docs/archived/PROCESS_DETECTION_FIX.md

Process Detection Bug Fix

Problem

The scripts couldn't find running Gradio processes because:

Original Pattern: grep "[p]ython.*app_gradio.py"

Actual Process:

/Library/Frameworks/Python.framework/Versions/3.12/Resources/Python.app/Contents/MacOS/Python web/app_gradio.py

The full path is Python (capital P) in .app/Contents/MacOS/, not python (lowercase).

Root Cause

macOS Python.app wraps the interpreter in:

Python.app/Contents/MacOS/Python

So the process name is Python not python.

Solution

1. Better grep Pattern

# Before (failed):
grep "[p]ython.*app_gradio.py"

# After (works):
grep -E "[P]ython.*app_gradio|[p]ython.*app_gradio"

Matches both:

• Python (macOS .app wrapper)
• python (direct interpreter)
• python3 (version-specific)

2. Port-Based Fallback

If grep fails, check port 7860 directly:

# Find processes using port 7860
PORT_PIDS=$(lsof -ti:7860 2>/dev/null)

if [ -n "$PORT_PIDS" ]; then
    echo "⚠️  Found process(es) using port 7860"
    # Kill them
    for PID in $PORT_PIDS; do
        kill -9 $PID
    done
fi

Updated Scripts

stop_gradio.sh

# Find processes
PIDS=$(ps aux | grep -E "[P]ython.*app_gradio|[p]ython.*app_gradio" | awk '{print $2}')

# If none found, check port as fallback
if [ -z "$PIDS" ]; then
    PORT_PIDS=$(lsof -ti:7860 2>/dev/null)
    if [ -n "$PORT_PIDS" ]; then
        # Kill processes on port
    fi
fi

restart_gradio.sh

# Same grep pattern
PIDS=$(ps aux | grep -E "[P]ython.*app_gradio|[p]ython.*app_gradio" | awk '{print $2}')

# Port fallback after killing
PORT_PIDS=$(lsof -ti:7860 2>/dev/null)
if [ -n "$PORT_PIDS" ]; then
    kill -9 $PORT_PIDS
fi

Testing

Before Fix

$ ./stop_gradio.sh
✓ No running Gradio server found

$ lsof -i:7860
# Shows process still running!

After Fix

$ ./stop_gradio.sh
Found running Gradio server(s):
alexchilton 68650 ... Python web/app_gradio.py

🔪 Killing process 68650...
✓ All Gradio processes stopped

$ lsof -i:7860
# Port is free ✅

Why This Matters

Scenario 1: Port Already in Use

Before:

./start_gradio.sh
# Error: Address already in use
# Manual: ps aux | grep gradio, find PID, kill, retry

After:

./start_gradio.sh
# ✓ Finds and kills old process
# ✓ Frees port 7860
# ✓ Starts new server

Scenario 2: Invisible Processes

Before: Script says "no server found" but port is blocked
After: Fallback checks port and kills blocking process

Platform Compatibility

macOS

• ✅ Matches Python.app/Contents/MacOS/Python
• ✅ Fallback with lsof -ti:7860

Linux

• ✅ Matches /usr/bin/python3
• ✅ Fallback with lsof -ti:7860

Both

• ✅ Pattern matches case-insensitive Python variants
• ✅ Port-based detection as safety net

Edge Cases Handled

1. Multiple Python installations: Matches any Python variant
2. Zombie processes: Port fallback catches them
3. Process with different path: Regex allows flexibility
4. Port blocked by other process: lsof reports and kills it

Code Diff

- PIDS=$(ps aux | grep "[p]ython.*app_gradio.py" | awk '{print $2}')
+ PIDS=$(ps aux | grep -E "[P]ython.*app_gradio|[p]ython.*app_gradio" | awk '{print $2}')

  if [ -z "$PIDS" ]; then
-     echo "✓ No running Gradio server found"
-     exit 0
+     echo "✓ No running Gradio server found"
+     echo ""
+     echo "💡 Checking for processes using port 7860..."
+     PORT_PIDS=$(lsof -ti:7860 2>/dev/null)
+     if [ -n "$PORT_PIDS" ]; then
+         echo "⚠️  Found process(es) using port 7860"
+         # Kill them
+     fi
+     exit 0
  fi

User Experience

Before

User: "Port is in use but script says no server found"
Dev: "Try ps aux | grep gradio and kill manually"

After

User: ./stop_gradio.sh
Script: ✓ Found and killed Gradio on port 7860
User: ✓ Works!

Files Fixed

• ✅ stop_gradio.sh - Enhanced grep + port fallback
• ✅ restart_gradio.sh - Enhanced grep + port cleanup
• ✅ start_gradio.sh - Calls fixed stop_gradio.sh