Update app.py

app.py

@@ -11,6 +11,7 @@ from email.message import EmailMessage
 import matplotlib.pyplot as plt
 import numpy as np
 from collections import defaultdict
+from string import Template
 
 # Configuration
 CONFIG_FILE = "config.yaml"
@@ -25,10 +26,28 @@ class Monitor:
         self.incidents = defaultdict(list)
         
     def load_config(self):
+        # Load and substitute environment variables in the config
         with open(CONFIG_FILE, "r") as f:
-            config = yaml.safe_load(f)
+            config_content = f.read()
+        
+        # Replace ${VAR} with environment variables
+        config_content = Template(config_content).substitute(os.environ)
+        config = yaml.safe_load(config_content)
+        
+        # Set defaults
         config.setdefault('settings', {})
         config['settings'].setdefault('check_interval_seconds', 300)
+        
+        # Validate required environment variables
+        required_vars = ['SMTP_HOST', 'SMTP_PORT', 'SMTP_USERNAME', 'SMTP_PASSWORD', 'SMTP_FROM']
+        for var in required_vars:
+            if var not in os.environ:
+                raise ValueError(f"Missing required environment variable: {var}")
+        
+        # Add SMTP credentials from environment
+        config['settings']['smtp']['username'] = os.environ['SMTP_USERNAME']
+        config['settings']['smtp']['password'] = os.environ['SMTP_PASSWORD']
+        
         return config
 
     def load_data(self):