Summary

Create a handshake prose test to ensure that the opcode used for a load balanced handshake is OP_MSG, per the specifications:

https://github.com/mongodb/specifications/blob/master/source/load-balancers/load-balancers.rst#connection-establishment

https://github.com/mongodb/specifications/blob/master/source/mongodb-handshake/handshake.rst#connection-handshake

Motivation

The Go Driver has always incorrectly used OP_QUERY for load-balanced connection handshakes. The Drivers team should test for this case.

Who is the affected end user?

Affected end user is anyone connecting to the Atlas proxy (Serverless)

How does this affect the end user?

Confusing log messages shown

How likely is it that this problem or use case will occur?

Main path? Edge case?

If the problem does occur, what are the consequences and how severe are they?

Minor annoyance at a log message? Performance concern? Outage/unavailability? Failover can't complete?

Is this issue urgent?

Does this ticket have a required timeline? What is it?

Is this ticket required by a downstream team?

Needed by e.g. Atlas, Shell, Compass?

Is this ticket only for tests?

Yes

Acceptance Criteria

Extend the handshake prose test to include:

(1) If the server is load balanced, then ensure that the handshake uses the OP_MSG opcode
(2) If not, ensure the handshake uses OP_QUERY