MongoDB Node.js Driver 3.6.0 Released

The MongoDB Node.js team is pleased to announce version 3.6.0 of the driver, supporting the MongoDB 4.4 release.

Release Highlights

Streaming topology changes

MongoDB drivers maintain a local view of the topology they are connected to, and ensure the accuracy of that view by polling connected nodes on average every ~10s. In MongoDB 4.4, drivers are now able to receive push notifications about topology updates, effectively reducing the time for client recovery in failover scenarios to the time it takes for the server to make the election and report the outcome.

This feature is enabled by default when connecting to MongoDB 4.4, no changes are needed for user code.

Authentication

MONGODB-AWS authentication mechanism

The MONGODB-AWS authentication mechanism uses your Amazon Web Services Identity and Access Management (AWS IAM) credentials to authenticate users on MongoDB 4.4+. Please read more about this new authentication mechanism in our documentation.

Performance improvements

There were two projects to transparently improve performance of authentication in MongoDB 4.4:

  • A driver can now include the first saslStart command in its initial handshake with server. This so-called “speculative authentication” allows us to reduce one roundtrip to the server for authentication a connection. This feature is only support for X.509, SCRAM-SHA-1 and SCRAM-SHA-256 (default) authentication mechanisms.

  • The SCRAM conversation between driver and server can now skip one of it’s empty exchanges which also serves to reduce the roundtrips during a SCRAM authentication.

OCSP stapling testing

OCSP stapling greatly improves performance when using LetsEncrypt certificates, removing the need for an external request to LetsEncrypt servers for each authentication attempt. No additional changes were required to support OCSP stapling in the driver, but extensive testing was added to verify that the feature works as expected.

Changes in behavior of Db.prototype.createCollection

The createCollection helper used to internally run a listCollections command in order to see if a collection already existed before running the command. If it determined a collection with the same name existed, it would skip running the command and return an instance of Collection. This behavior was changed in v3.6.0 to avoid potentially serious bugs, specifically that the driver was not considering options passed into createCollection as part of the collection equality check. Imagine the following scenario:

const client = new MongoClient('...');
await client.connect();
 
await client.db('foo').collection('bar').insert({ importantField: 'llamas' });
await client.db('foo').createCollection('bar', {
  validator: { $jsonSchema: {
    bsonType: 'object',
    required: ['importantField'],
    properties: { name: { bsonType: 'boolean' } }
  }
});

The createCollection call which defines a JSON schema validator would be completely bypassed because of the existence of bar, which was implicitly created in the first command. Our policy is strictly adhere to semver, but in rare cases like this where we feel there is potential for a data corrupting bug, we make breaking behavioral changes to protect the user.

Documentation

Reference: http://mongodb.github.io/node-mongodb-native/3.6/
API: http://mongodb.github.io/node-mongodb-native/3.6/api/
Changelog: https://github.com/mongodb/node-mongodb-native/blob/3.6/HISTORY.md
Release Notes: https://jira.mongodb.org/secure/ReleaseNote.jspa?projectId=10880&version=25030

We invite you to try the driver immediately, and report any issues to the NODE project.

Thanks very much to all the community members who contributed to this release!

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