Back up MongoDB (Atlas) to S3 through Lambda

Back up a MongoDB database to AWS S3 through a simple AWS Lambda function by using the mongodump binary. Result is a ZIP archive with .bson and .metadata.json files for each collection.

For a MongoDB Atlas cluster database backup, specify the URI command option like this:

--uri "mongodb+srv://[user]:[pass]@[host]/[name]"

Adapted from alonhar/lambda-mongodb-s3-backup.

mongodump binary is version 100.7.4 (mongodb-database-tools-amazon2-x86_64-100.7.4)

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Setup instructions

1. Clone and install dependencies
2. ZIP contents of the folder (not the folder itself)
3. Create an AWS Lambda function
   • Select 'Author from scratch', enter your function name and select Node.js 18.x
   • Choose an existing role or create a new one and make sure it has a policy with s3:PutObject and s3:ListBucket permissions for the S3 bucket that you want to back up to, as well as the AWSLambdaBasicExecutionRole policy
   • Upload the ZIP file
   • Under the Configuration tab, set the environment variables (see table below) and increase the timeout (e.g. 1min), ephemeral storage (e.g. 1024 MB) and memory (e.g. 512 MB) (depending on the size of your database, you may need to adjust these settings)
   • Configure a trigger. For instance, with EventBridge you can set up a cron schedule

Environment variables

Variable	Description	Required?
MONGODUMP_OPTIONS	Your mongodump command options separated by a space (without mongodump at the beginning), for instance --uri "mongodb+srv://[user]:[pass]@[host]/[name]" Refer to the mongodump docs for a list of available options. Important: do not include the --out or -o option.	Yes
S3_BUCKET	Name of the S3 bucket	Yes
S3_STORAGE_CLASS	S3 storage class for the backup. Refer to the S3 SDK docs for a list of available options.	No. Default is STANDARD
ZIP_FILENAME	Name of the ZIP archive	No. Default is mongodb_backup
FOLDER_PREFIX	Name of the Parent folder	No. Default is mongodb_backups
DATE_FORMAT	Will be appended to ZIP_FILENAME with a _ separator. Refer to the DayJS docs for a list of available formatting options.	No. Default is YYYYMMDD_HHmmss

Changelog

v2.0.0

• Rewritten using async/await
• Use of adm-zip instead of archiver
• Improved error handling and logging
• Updated mongodump to 100.7.4
• Updated dependencies
• Updated docs

v1.2.0

• Updated mongodump from 4.0.5 to 100.1.1
• The Mongo connection string is no longer fixed at a certain format. You now have the flexibility to specify the URI or host in the format you need, as well as other mongodump command options.
• There is a new env variable through which you can specify the ZIP filename (it is no longer the database name)
• The uploaded archive is now automatically AES256 encrypted on S3
• The S3 storage class is now defined on the file level instead of the bucket level
• Replaced 'zip-a-folder' by 'archiver'
• Updated docs