Project: Python Resource Monitor

In this project, you will build a production-grade server watchdog script. This tool monitors CPU and RAM usage and sends an automated email alert if any resource exceeds a defined threshold.

Prerequisites

• Python 3.x installed.
• psutil: A library for retrieving information on running processes and system utilization.
• smtplib: Python's built-in library for sending emails via SMTP.
• App Password: Required if you're using Gmail or similar providers for security.

Step 1: Install Dependencies

Open your terminal and install the psutil library.

pip install psutil

Step 2: Create the Watchdog Script

Create a file named resource_monitor.py and add the following logic.

import psutil
import smtplib
import time
import logging
 
# --- CONFIGURATION ---
CPU_THRESHOLD = 80    # Trigger alert if > 80%
RAM_THRESHOLD = 75    # Trigger alert if > 75%
CHECK_INTERVAL = 60   # Seconds between checks
 
# Email Settings (Use Environment Variables for Production!)
EMAIL_FROM = "your-email@gmail.com"
EMAIL_TO = "admin@example.com"
EMAIL_PW = "your-app-password" # App-specific password
SMTP_SERVER = "smtp.gmail.com"
SMTP_PORT = 587
 
def send_alert(message):
    try:
        with smtplib.SMTP(SMTP_SERVER, SMTP_PORT) as server:
            server.starttls()
            server.login(EMAIL_FROM, EMAIL_PW)
            server.sendmail(EMAIL_FROM, EMAIL_TO, f"Subject: SERVER ALERT!\n\n{message}")
        print("✅ Alert email sent successfully.")
    except Exception as e:
        print(f"❌ Failed to send email: {e}")
 
while True:
    cpu_usage = psutil.cpu_percent(interval=1)
    ram_usage = psutil.virtual_memory().percent
    
    print(f"[{time.ctime()}] CPU: {cpu_usage}% | RAM: {ram_usage}%")
    
    if cpu_usage > CPU_THRESHOLD or ram_usage > RAM_THRESHOLD:
        alert_msg = f"Warning: Resource usage exceeded threshold. CPU: {cpu_usage}%, RAM: {ram_usage}%"
        send_alert(alert_msg)
        
    time.sleep(CHECK_INTERVAL)

Step 3: Security Basics (App Passwords)

Modern email providers (like Gmail) do not allow basic login for scripts. You must create an App Password:

1. Go to your Google Account settings.
2. Search for App Passwords.
3. Select "Other" and name it "Python Monitor".
4. Use the generated 16-character code in your EMAIL_PW variable.

Step 4: Run and Test

Execute your script in the background or a terminal session:

python3 resource_monitor.py

How to Verify

To test the alert logic, you can temporarily lower your thresholds to 10% inside the script. This will trigger an alert based on your normal background activity.

Summary of Logic

[!CAUTION] Hardcoded Passwords Never commit your email passwords to Git. For production systems, use environment variables (os.environ.get('EMAIL_PW')) or a secrets manager.