Function wrapMongoDBWithLatency

benchmark/MongoLatencyWrapper.js:79–133

* Wrap MongoDB Collection methods with artificial latency * @param {number} latencyMs - Delay in milliseconds to inject before each operation * @returns {Function} unwrap - Function to restore original methods

(latencyMs)

 * @returns {Function} unwrap - Function to restore original methods
 */
function wrapMongoDBWithLatency(latencyMs) {
  if (typeof latencyMs !== 'number' || latencyMs < 0) {
    throw new Error('latencyMs must be a non-negative number');
  }

  if (latencyMs === 0) {
    // eslint-disable-next-line no-console
    console.log('Latency is 0ms, skipping MongoDB wrapping');
    return () => {}; // No-op unwrap function
  }

  // eslint-disable-next-line no-console
  console.log(`Wrapping MongoDB operations with ${latencyMs}ms artificial latency`);

  // List of MongoDB Collection methods to wrap
  const methodsToWrap = [
    'find',
    'findOne',
    'countDocuments',
    'estimatedDocumentCount',
    'distinct',
    'aggregate',
    'insertOne',
    'insertMany',
    'updateOne',
    'updateMany',
    'replaceOne',
    'deleteOne',
    'deleteMany',
    'findOneAndUpdate',
    'findOneAndReplace',
    'findOneAndDelete',
    'createIndex',
    'createIndexes',
    'dropIndex',
    'dropIndexes',
    'drop',
  ];

  methodsToWrap.forEach(methodName => {
    wrapMethod(methodName, latencyMs);
  });

  // Return unwrap function to restore original methods
  return function unwrap() {
    // eslint-disable-next-line no-console
    console.log('Removing MongoDB latency wrapper, restoring original methods');

    originalMethods.forEach((originalMethod, methodName) => {
      Collection.prototype[methodName] = originalMethod;
    });

    originalMethods.clear();
  };
}

module.exports = {
  wrapMongoDBWithLatency,