v3.0.0-beta

The MongoDB Rust driver team is pleased to announce the v3.0.0-beta release of the mongodb crate, now available for download from crates.io.

Highlighted Changes

Breaking Changes

3.0 introduces a wide variety of improvements that required backwards-incompatible API changes; in most cases these changes should require only minor updates in application code.

Most notably:

• Fluent API: Async methods that accepted options have been updated to allow the individual options to be given directly in line with the call to reduce required boilerplate.
• Events: 3.0 introduces the EventHandler type, which can be constructed from a callback, async callback, or an async channel sender.
• Async Runtime: 3.0 only supports tokio; support for async-std has been discontinued.

For detailed information on breaking changes and examples of migrating from 2.x to 3.0, please see the migration guide.

Bulk Write

The Rust driver now implements the new Bulk Write specification, which supports performing mixed write operations against multiple namespaces in a minimized number of round-trips to the server. This feature is only available for early testing using MongoDB 8.0 release candidate binaries. This feature is not recommended for use in production until the stable release of MongoDB 8.0.

OIDC Authentication

The Rust driver can now authenticate using an OpenID Connect access token, including support for both the machine and human authentication flows, and automatic token acquisition for Azure and GCP.

Included Changes

Below are a selected list of other changes with user impact; for a full list of changes see this GitHub query.

Breaking Changes

• RUST-1810 Clean up concern helpers (#1011)
• RUST-1603 Support the authorized_collections option (#1033)
• RUST-1876 Require T: Send + Sync for Collection (#1043)
• RUST-1306 Move Compression enum behind compression feature flags (#1055)
• RUST-1563 Make ReadPreferenceOptions optional (#1059)
• RUST-1208 Future-proof features (#1062)
• RUST-1764 Drop human_readable options in favor of HumanReadable (#1064)
• RUST-1695 Use consistent defaults for TypedBuilder (#1072)
• RUST-1364 Collapse comment and comment_bson (#1070)

New Features

• RUST-1652 Add a find_one method to GridFsBucket (#1015)
• RUST-1856 expose Database::client (#1035) (thanks @dgrijalva!)
• RUST-1830 Support KMIP delegated protocol (#1115)

Improvements

• chore: bump socket2 to 0.5 (#1020) (thanks @attila-lin!)
• chore: move lazy_static to once_cell (#1022) (thanks @attila-lin!)
• RUST-1631 Always use polling monitoring when running in a FaaS environment (#1030)

Bugfixes

• RUST-1881 Check integer conversions (#1045)