Make RacksDB dependency optional

[faganihajizada]

Summary

RacksDB is marked as an optional dependency in pyproject.toml under the [agent] extra, but the code has unconditional imports at the module level:

from racksdb.errors import RacksDBSchemaError, RacksDBFormatError
from racksdb.web.app import RacksDBWebBlueprint

This causes ModuleNotFoundError when running the agent without RacksDB installed.

Solution

This PR makes RacksDB imports conditional using the existing werkzeug optional import pattern found in the codebase (slurmweb/apps/agent.py):

• Module-level try/except: Wrap RacksDB imports in try/except ModuleNotFoundError block
• Stub exception classes: Provide stub classes to satisfy Python's exception handling requirements
• Configuration validation: Fail early with clear error message if RacksDB is enabled but not installed
• Graceful fallbacks: Version display shows "N/A (not installed)" when RacksDB is unavailable

Testing

• All tests pass with RacksDB mocked as available
• Agent starts successfully without RacksDB when racksdb.enabled=false
• Clear error message when racksdb.enabled=true but RacksDB not installed
• Deployed and tested

[faganihajizada]

@rezib this one is ready for review. thank you!

[rezib]

Thank you @faganihajizada for this PR! I have a few comments and a question: how do you manage to install Slurm-web without RacksDB in your case? You're not making RacksDB an optional dependency in pyproject.toml. RPM and deb packages have a strong dependency on RacksDB. What's your plan?

[faganihajizada]

Thank you @faganihajizada for this PR! I have a few comments and a question: how do you manage to install Slurm-web without RacksDB in your case? You're not making RacksDB an optional dependency in pyproject.toml. RPM and deb packages have a strong dependency on RacksDB. What's your plan?

Thanks for review @rezib

In our case, we're building Docker containers for Kubernetes deployments. In our Dockerfile, instead of pip install .[agent] we do pip install ClusterShell prometheus-client redis requests ....

This allows us to install the agent dependencies individually while excluding RacksDB from our container images. My goal here is to keep traditional installations with pip install .[agent] continue to work exactly as before, including RPM/deb packages.

I am planning to contribute and help you with container images and helm charts for k8s deployments if you are interested.

[rezib]

In our case, we're building Docker containers for Kubernetes deployments. In our Dockerfile, instead of pip install .[agent] we do pip install ClusterShell prometheus-client redis requests ....

This allows us to install the agent dependencies individually while excluding RacksDB from our container images. My goal here is to keep traditional installations with pip install .[agent] continue to work exactly as before, including RPM/deb packages.

OK thanks for these explanations!

I am planning to contribute and help you with container images and helm charts for k8s deployments if you are interested.

Oh yes, of course!

[rezib]

Thank you @faganihajizada for this contribution!