Fixing Production Issues Not Present in Lovable Local Preview

 
Step One: Create Global Error Handlers
 

• In your main JavaScript file (for example, index.js), add the following code near the top. This code will catch unexpected errors that occur only in production:

  
  function logError(err) {
    // This will log production errors for later review.
    console.error('Production Error Detected:', err);
  }
  
  process.on('uncaughtException', logError);
  process.on('unhandledRejection', logError);
      

  
  


• This code makes sure that any errors are captured and logged, helping you diagnose issues that only appear when running in production.

 
Step Two: Set Up a Production Configuration File
 

• Create a new file named production.json in your project. This file will store production-specific settings.

  
  {
    "env": "production",
    "debug": false,
    "logging": {
      "level": "error"
    }
  }
      

• This file tells your application it’s running in production mode and adjusts settings like debugging and logging levels accordingly.

 
Step Three: Load the Production Configuration
 

• Create or open your configuration loader script (for instance, config.js). Insert the following code so your app can read production.json:

  
  var fs = require('fs');
  
  try {
    var config = JSON.parse(fs.readFileSync('production.json', 'utf8'));
    if (config.env === 'production') {
      // Set environment-specific variables.
      process.env.NODE_ENV = 'production';
      process.env.DEBUG = config.debug;
    }
  } catch (err) {
    console.error('Error reading production configuration:', err);
  }
      

  
  


• This ensures your application loads and applies production settings every time it starts.

 
Step Four: Embed a Logging Dependency Manually
 

• Since Lovable doesn’t have a terminal to install dependencies, you should include the needed logging functionality directly into your project.
• Create a new file named winston.js inside a folder called dependencies (create the folder if it doesn’t exist). Paste the following minimal logging code:

  
  // This is a simplified version of a logging library.
  var winston = {
    log: function(level, msg) {
      if (level === 'error') {
        console.error('Logged Error:', msg);
      }
    }
  };
  
  module.exports = winston;
      

  
  


• Now, in your main application file (for example, index.js), import this logging module with:
  

  
  var winston = require('./dependencies/winston');
      

  
  

 
Step Five: Implement Production-Specific Error Handling Middleware
 

• If your application handles requests (for example, using Express), add production-specific error responses. In your error handling middleware, use the following code:

  
  function handleError(err, req, res, next) {
    if (process.env.NODE\_ENV === 'production') {
      // Respond with a generic message and log the detailed error.
      res.status(500).send('An error occurred. Please try again later.');
      winston.log('error', err.stack);
    } else {
      // In non-production, you might want to see the full error stack.
      res.status(500).send(err.stack);
    }
  }
      

• Place this middleware after all other routes in your main file to catch errors during request processing.

 
Enhancing Logging for Production Stability
 

• In your main project directory for Lovable, create a new file named logger.py. This file will help you record what happens in your application so you can understand issues later.
• Add the following snippet to logger.py. This code sets up a logging system that saves messages to a file, which is very useful when your production code runs without a visible terminal:

• 
  import os
  import datetime
  
  def log_message(message, level="INFO"):
      log_dir = "logs"
      if not os.path.exists(log_dir):
          os.makedirs(log_dir)
      today = datetime.date.today().strftime("%Y-%m-%d")
      log_file = os.path.join(log_dir, f"{today}.log")
      with open(log_file, "a") as f:
          timestamp = datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")
          f.write(f"[{timestamp}] [{level}] {message}\n")
        

  
  




• In your main code file (for example, main.py), import this logger by adding at the very top:




• 
  

  
  from logger import log_message
        

  
  




• Use the function log_message throughout your code wherever you want to record important events or errors.

 
Implementing Robust Error Handling
 

• Navigate to the parts of your code where errors might occur. Wrap these sections with a try/except block to catch exceptions. This practice prevents the application from crashing by handling errors gracefully.
• Insert the following snippet within your functional logic. For instance, in main.py, around any call that might throw an error:

• 
  try:
      # Your normal processing code here, e.g. connecting to a database or processing user input
      process_user_data()
  except Exception as e:
      log\_message(f"Error occurred: {str(e)}", level="ERROR")
      # Optionally, you may add additional error handling or fallback mechanisms here
        

• This method logs the error and allows your program to continue running or to perform a controlled shutdown.

 
Setting Up Production Configurations
 

• Create a new file in your project directory called production\_config.py. This file will hold settings that define how your code runs in production, such as debugging flags or connection parameters.
• Add this snippet to production\_config.py to separate production settings from development ones:

• 
  production\_config.py
  
  DEBUG = False
  DATABASE_URI = "your-production-database-uri"
  LOG_LEVEL = "INFO"
        

  
  




• In your main code file, import this configuration. At the very beginning of main.py, add:




• 
  

  
  from production_config import DEBUG, DATABASE_URI, LOG_LEVEL
        

  
  




• Now your code can adjust its behavior via these configurable parameters to ensure stability in production.

 
Introducing Monitoring and Health Checks
 

• It is important to know if your application is running correctly. Create a new file called health\_check.py in your project directory.
• Insert the following code snippet in health\_check.py to create a basic health check endpoint that can be monitored:

• 
  def health():
      try:
          # Perform simple checks such as file access or database connection here
          status = "OK"
      except Exception:
          status = "FAIL"
      return status
  
  if name == "main":
      # This allows testing the endpoint manually if needed
      result = health()
      print(f"Application Health: {result}")
        

  
  




• In your main code, if you have an HTTP server, consider adding an endpoint (for instance, /health) that calls the health() function. This makes it easier for monitoring tools to check the system’s status.

 
Automating Dependency Management Without a Terminal
 

• Because Lovable does not provide terminal access, you must ensure that required libraries are automatically available. Insert code at the start of your main file (main.py) to check and install missing dependencies.
• Add the following snippet at the very beginning of main.py:

• 
  import importlib
  import subprocess
  import sys
  
  def install_if_missing(package):
      try:
          importlib.import_module(package)
      except ImportError:
          subprocess.check_call([sys.executable, "-m", "pip", "install", package])
  Example: Ensure the 'requests' library is installed
  install_if_missing("requests")
        

  
  




• This code checks for the presence of a library (like requests) and installs it if missing, ensuring your production code has all dependencies it needs.

 
Setting Up Automated Recovery and Alerts
 

• Set up a simple mechanism in your main code to automatically alert you and attempt recovery when a serious error occurs. For example, in main.py, after logging a critical error, send an alert using a basic email function.
• Create a file called alerts.py with the following content:

• 
  import smtplib
  
  def send_alert(message):
      # Set up your email server configuration here
      server = smtplib.SMTP("smtp.example.com", 587)
      server.starttls()
      server.login("your-email@example.com", "your-password")
      subject = "Production Alert"
      body = f"Subject: {subject}\n\n{message}"
      server.sendmail("your-email@example.com", "alert-recipient@example.com", body)
      server.quit()
        

  
  




• Then, in main.py, you can call this alert function when a critical issue is caught:




• 
  

  
  from alerts import send_alert
  
  try:
      critical_task()
  except Exception as e:
      log_message(f"Critical failure: {str(e)}", level="CRITICAL")
      send_alert(f"Critical failure encountered: {str(e)}")
        

  
  




• This ensures that you are informed quickly and can take action, increasing the stability of your production environment.