Summary

Prevent mongo-orchestration setup-and-run failure when a new PyMongo release drops support for an old MongoDB Server version by locking the package dependencies of Python scripts in Drivers Evergreen Tools (DET), in particular for scripts related to mongo-orchestration.

Motivation

Who is the affected end user?

Users depending on Drivers Evergreen Tools to setup-and-run mongo-orchestration.

How does this affect the end user?

When a new PyMongo release drops support for an MongoDB Server version, EVG tasks for downstream projects depending on mongo-orchestration via DET may unexpectedly fail with an error similar to:

pymongo.errors.ConfigurationError: Server at localhost:27017 reports wire version 7, but this version of PyMongo requires at least 8 (MongoDB 4.2).

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

Whenever a new PyMongo release drops support for an old MongoDB Server version. This is due to the absence of minor version constraints on the pymongo package dependency, which is required by the mongo-orchestration project, thereby obtaining the latest release (at the time of script execution) by default.

Note: DET currently obtains mongo-orchestration as a Git dependency source.

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

Unexpected EVG task failures within downstream projects using mongo-orchestration via DET scripts, which may disrupt regular development workflows.

Is this issue urgent?

No. The manual workaround is straightforward: a new constraint must be added to install-cli.sh as done for 3.6 and 4.0. However, the resolution to this ticket would prevent the unexpected EVG task failures in downstream projects in advance of applying the appropriate workarounds for a new PyMongo release.

Is this ticket required by a downstream team?

No.

Is this ticket only for tests?

Yes.

Acceptance Criteria

The DET-provided mongo-orchestration setup-and-run routines should not be affected by a new PyMongo release that drops support for an old MongoDB Server version.