python_automation

```python
import requests
from bs4 import BeautifulSoup
import pandas as pd
import logging
from datetime import datetime

# Configure logging
logging.basicConfig(filename='email_scraper.log', level=logging.INFO, 
                    format='%(asctime)s - %(levelname)s - %(message)s')

# Constants
TARGET_URL = "https://example-forum.com/threads/lead-generation"
OUTPUT_FILE = "forum_emails.csv"
MAX_PAGES = 5

# User-Agent to mimic browser
HEADERS = {'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36'}

# Email regex pattern
import re
EMAIL_REGEX = r'\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b'

def scrape_forum_emails(url, max_pages=5):
    """Scrape emails from forum threads and return as DataFrame"""
    emails = []
    
    for page in range(1, max_pages + 1):
        try:
            response = requests.get(f"{url}?page={page}", headers=HEADERS, timeout=10)
            response.raise_for_status()
            
            soup = BeautifulSoup(response.text, 'html.parser')
            threads = soup.find_all('div', class_='thread')
            
            for thread in threads:
                thread_title = thread.find('h3').text.strip()
                content = thread.find('div', class_='message').text
                
                # Find all emails in thread content
                found_emails = re.findall(EMAIL_REGEX, content)
                emails.extend(found_emails)
                
                logging.info(f"Page {page}: Found {len(found_emails)} emails in '{thread_title}'")
                
        except requests.RequestException as e:
            logging.error(f"Error scraping page {page}: {str(e)}")
            continue
    
    return pd.DataFrame({'email': list(set(emails))})

if __name__ == "__main__":
    logging.info("Starting forum email scraping...")
    
    try:
        df_emails = scrape_forum_emails(TARGET_URL, MAX_PAGES)
        
        if not df_emails.empty:
            df_emails.to_csv(OUTPUT_FILE, index=False)
            logging.info(f"Successfully saved {len(df_emails)} unique emails to {OUTPUT_FILE}")
            print(f"Scraping complete! Found {len(df_emails)} unique emails.")
        else:
            logging.warning("No emails found in the specified pages.")
            print("No emails found. Check the target URL or adjust scraping parameters.")
            
    except Exception as e:
        logging.error(f"Script failed: {str(e)}")
        print(f"Error occurred: {str(e)}")
```

**Output Explanation:**
This script scrapes email addresses from forum threads by:
1. Iterating through 5 pages of a target forum
2. Extracting email patterns from thread content using regex
3. Deduplicating results and saving to a CSV file
4. Logging all actions and errors for debugging

The script handles common issues like:
- Rate limiting by using a browser-like User-Agent
- Network timeouts with a 10-second limit
- Malformed HTML with BeautifulSoup's robust parser
- Duplicate emails by converting to a set before saving

When run, it would typically output something like:
```
Starting forum email scraping...
Page 1: Found 12 emails in 'Best CRM Tools for 2024'
Page 2: Found 8 emails in 'Email Marketing Strategies'
Page 3: Found 5 emails in 'Lead Generation Hacks'
Page 4: Found 0 emails in 'Off-topic discussions'
Page 5: Found 3 emails in 'B2B Sales Techniques'
Successfully saved 28 unique emails to forum_emails.csv
Scraping complete! Found 28 unique emails.
```