Database Infrastructure

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Overview

PyqDeck uses MongoDB Atlas as its production database provider and Mongoose as the Object Data Modeling (ODM) library for Node.js.

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Production Setup (MongoDB Atlas)

• Cluster: We use a multi-region cluster for high availability and low latency.
• Connection: Managed via the MONGODB_URI environment variable.
• Security:
  • IP Whitelisting: Only authorized application servers and CI/CD runners can connect.
  • Authentication: SCRAM-SHA-1 or X.509 certificates.
  • Encryption: Data is encrypted at rest (AES-256) and in transit (TLS/SSL).

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Connection Management

The database connection is initialized in backend/src/database.js.

• Singleton Pattern: We ensure only one connection instance exists throughout the application lifecycle.
• Configuration:
  const options = {
    autoIndex: true, // Enabled in dev, usually disabled in production for performance
    maxPoolSize: 10, // Maintain up to 10 socket connections
    serverSelectionTimeoutMS: 5000, // Keep trying to send operations for 5 seconds
    socketTimeoutMS: 45000, // Close sockets after 45 seconds of inactivity
  };
  

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Indexing Strategy

To ensure high performance as the dataset grows, we define indexes in our Mongoose models:

• Unique Indexes: On slugs and email addresses.
• Compound Indexes: For common query patterns (e.g., universityId + branchId + semesterId).
• TTL Indexes: For temporary data like OTPs (if stored in MongoDB).
• Text Indexes: For basic global search functionality across universities and subjects.

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Testing with mongodb-memory-server

For unit and integration tests, we do not use a live MongoDB instance. Instead, we use mongodb-memory-server.

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Benefits

• Isolation: Each test run starts with a clean, empty database.
• Speed: Operations are performed in memory, making tests significantly faster.
• Reliability: Tests don’t fail due to network issues or shared state in a physical dev database.

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Setup (backend/tests/setup.js)

The test runner automatically:

1. Starts an in-memory MongoDB instance.
2. Sets the MONGODB_URI to the memory server’s address.
3. Clears all collections between test cases to ensure idempotency.
4. Shuts down the server after all tests are complete.