MongoDB Document Trigger

A comprehensive audit logging system for MongoDB that automatically tracks and logs every document change in real-time using MongoDB Change Streams and Database Triggers.

How It Works?

Step-by-Step Process

1. Change Detection: When any document in your MongoDB database is modified (insert, update, delete, replace), MongoDB's Change Stream automatically detects the change
2. Trigger Activation: The database trigger (Trigger.js) is instantly activated with the change event details
3. Field Analysis: The trigger analyzes the change at the field level, comparing old vs new values
4. Audit Log Creation: For each changed field, a separate audit log entry is created with complete metadata
5. Storage: Audit logs are stored in dedicated collections (e.g., users_logs for users collection)
6. Web Interface: The Next.js dashboard provides real-time access to view, search, and analyze all audit data

What Gets Logged?

For Each Changed Field:

• Document ID of the affected record
• Operation Type (INSERT, UPDATE, DELETE, REPLACE)
• Changed Filed (including nested fields)
• Old value (before change)
• New value (after change)
• Updated By (User who made the change)
• Exact timestamp of the change

Example: When a user updates their email from old@email.com to new@email.com, the system creates:

{
  "documentId": "507f1f77bcf86cd799439011",
  "operationType": "update",
  "changedFields": "email",
  "oldValue": "old@email.com",
  "newValue": "new@email.com",
  "updatedBy": "admin@email.com",
  "timestamp": "2025-06-12T10:30:00.000Z"
}

User Interface Guide

Home Page (http://localhost:3000/)

What You'll See:

• Create User Tab: Form to add new users with name, email, role, and complete address
• Manage Users Tab: Table showing all users with edit/delete buttons
• Real-time Updates: User list automatically refreshes after any operation

What Gets Audited:

• Every user creation, update, and deletion
• Field-level changes (name, email, role, address components)

Audit Logs Page (http://localhost:3000/logs)

What You'll See:

• Collection Selector: Dropdown to choose which collection's logs to view
• Search & Filters:
  • Global search across all fields
  • Document ID filter
  • Changed field filter
• Document Summary Table: Shows documents that have been modified with:
  • Document ID (clickable for detailed history)
  • Last operation performed
  • Last modification timestamp

How to Use:

1. Select a Collection from the dropdown
2. Use filters to narrow down results
3. Click any document ID to see detailed change history

Document History Page (http://localhost:3000/document/[id])

What You'll See:

• Document Information: Document ID
• Complete Change Timeline: Chronological table showing:
  • Operation Type (INSERT/UPDATE/DELETE)
  • Changed Field
  • Previous Value
  • New Value
  • Updated By
  • Timestamp

How to Access:

• Click any document ID in the logs page
• Or navigate directly: /document/[documentId]?collection=[collectionName]

Setup Guide

Step 1: Project Setup

# Clone the repository
git clone https://github.com/sujeethshingade/mongodb-document-trigger.git
cd mongodb-document-trigger

# Install dependencies
npm install

# Create environment file
touch .env.local

Step 2: MongoDB Atlas Configuration

# Edit .env.local with your credentials
MONGODB_URI=your_mongodb_connection_string

# MongoDB Atlas API Configuration for Triggers Setup
ATLAS_PUBLIC_KEY=your_atlas_public_key_here
ATLAS_PRIVATE_KEY=your_atlas_private_key_here
ATLAS_PROJECT_ID=your_atlas_project_id_here
ATLAS_APP_ID=your_atlas_app_id_here

How to Get Atlas Credentials?

1. API Keys: Atlas → Access Manager → Project Access → Applications → API Keys → Create a new key
2. Project ID: Atlas → Project Settings
3. App ID: Atlas → App Services → Create App Service → App Settings

Step 3: Deploy Database Triggers

Option A: Automated Deployment (Recommended)

# Deploy the audit function to Atlas App Services
npm run deploy-functions

# Create triggers automatically from triggers.json
npm run setup-triggers

Configure Triggers for Your Collections:

Edit triggers/triggers.json to match your collections:

[
  {
    "name": "trigger_name",    // Adjust trigger name as requried
    "type": "DATABASE",
    "disabled": false,
    "function_name": "auditLogFunction",
    "config": {
      "operation_types": ["INSERT", "UPDATE", "DELETE", "REPLACE"],
      "database": "your_database_name",    // Adjust database name as requried
      "collection": "collection_name",                 // Adjust collection name as requried for trigger to be setup on
      "service_name": "mongodb-document-trigger",
      "match": {},
      "full_document": true,
      "full_document_before_change": true
    }
  }      // Add more trigger objects for additional collections
]

Option B: Manual Setup via Atlas Dashboard

1. Create App Service:

   • Atlas → App Services → Create App Service
   • Choose your cluster and database
   • Note the App ID for your .env.local

2. Deploy Function:

   • App Services → Functions → Create New Function
   • Function Name: auditLogFunction
   • Copy contents from triggers/auditLogFunction.js
   • Save and Deploy

3. Create Triggers:

   • App Services → Triggers → Add Trigger
   • Trigger Details:
     • Trigger Type: Database
     • Watch Against: Collection
     • Cluster Name: Select your cluster
     • Database Name: Select your database
     • Collection Name: Select the collection to monitor
     • Operation Type: Select all (Insert, Update, Delete, Replace)
     • Full Document: ✅ Yes
     • Document Preimage: ✅ Yes (REQUIRED)

4. Function Configuration:

   • Auto-Resume: ✅ Yes
   • Event Ordering: ✅ Yes
   • Event Type: Function
   • Function: Select auditLogFunction or Copy and paste the entire contents of Trigger.js from this project and run
   • Trigger Name: Name the trigger
   • Save the trigger

5. Export Trigger App in App Services (Not Requried for Setup):

   • App Services → Select Created App → Deployment → Export App → Download as a .zip file

Step 4: Run the Application

# Start development server
npm run dev

# Or build for production
npm run build
npm start

Access the application at: http://localhost:3000

Bulk Trigger Management

The triggers/ directory contains:

• auditLogFunction.js - Main audit logging function
• triggers.json - Trigger definitions for bulk creation
• setup-triggers.js - Automated trigger creation script
• deploy-functions.js - Function deployment script

Important Notes

M0 (Free Cluster) Limitations:

• Auto-Resume: Not supported for bulk creation of triggers on M0 clusters (works on individual creation). Database triggers cannot automatically resume after failures.
• Change Stream Options: Implement Change Stream options not available on M0 clusters. Cannot set the retention time for pre- and post-images in change streams for requried time.