Serverless Tools - Mongo

Tools and utilities for working with MongoDB.

MongoClient

To use the MongoClient you can get a shared instance of the MongoClient by calling getMongoClient. This way the MongoClient is kept out of the handler and can be reused on Lambda invocations.

Authentication

The MongoClient options set by default use AWS IAM authentication.

Therefore the MongoClient will use the following environment variables to authenticate with the Lambda execution role.

• AWS_ACCESS_KEY_ID
• AWS_SECRET_ACCESS_KEY
• AWS_SESSION_TOKEN

You need to take care to create a MongoDB User for the AWS IAM role that is assigned to the Lambda function as its execution role.

See https://www.mongodb.com/docs/atlas/security/passwordless-authentication/ for more details.

Example Code

import { getMongoClient } from '@overlap/serverless-tools-mongo';

const { MONGO_URI, MONGO_DB_NAME } = process.env;

const mongoClient = await getMongoClient(MONGO_URI);
const collection = mongoClient.db(MONGO_DB_NAME);

If your handler takes a callback as its last argument, set the callbackWaitsForEmptyEventLoop property on the AWS Lambda Context object to false.

This allows a Lambda function to return its result to the caller without requiring that the MongoDB database connection be closed. Setting this property is not applicable for async handlers .

Deploy Collection

Use the deployCollection function to set up collections automatically on deployments.

A collection can be created or updated with different collection options. This way for example schema validations can be set.