fix(sidecar): honor worker namespace suffix in shared argument parsing

[tmonty12]

Summary

DYN_NAMESPACE_WORKER_SUFFIX identifies a worker generation during Kubernetes rolling updates. Appending it to the Dynamo namespace isolates worker generations and prevents cross-generation communication.

The Python entrypoint already applies this suffix in the integrated runtime/engine path. Sidecars previously ignored it. This change adds the same behavior to the shared CommonArgs namespace parser used by the vLLM, SGLang, and TensorRT-LLM sidecars:

• Unset or empty suffix: namespace unchanged.
• Non-empty suffix: <namespace>-<suffix>.

This applies to environment-provided, default, and explicit --namespace values.

Validation

• Two unit tests pass, covering unset/empty/populated suffixes, the default namespace, and CLI precedence.
• Formatting, changed-file pre-commit checks, and git diff --check pass.

Summary by CodeRabbit

• New Features

  • Namespace configuration now supports an optional worker suffix from the environment, appending it when provided.

• Bug Fixes

  • Empty or absent suffix values preserve the configured namespace.
  • Explicit namespace settings continue to take precedence as expected.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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📥 Commits

Reviewing files that changed from the base of the PR and between 395fb8e and 37c0fd1.

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• lib/backend-common/src/args.rs

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Walkthrough

The namespace argument parser now reads DYN_NAMESPACE_WORKER_SUFFIX. It appends a non-empty suffix to the namespace and preserves the namespace when the suffix is absent or empty. Tests cover environment, default, and CLI values.

Changes

Worker namespace suffix

Layer / File(s)	Summary
Parse and validate worker namespace lib/backend-common/src/args.rs	The namespace parser appends non-empty DYN_NAMESPACE_WORKER_SUFFIX values. Tests verify unchanged namespaces and suffixed namespaces from environment, default, and CLI inputs.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to 37c0f

The namespace suffix behavior is scoped to the shared parser and no actionable merge risk was identified.

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 66.67% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 3 functions across 1 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Description check	⚠️ Warning	The description explains the change and validation, but it does not follow the required template. It omits the Overview, Details, Where should the reviewer start?, and required Related Issues sections…	Add the required template sections. Include reviewer guidance, and complete the Related Issues section by linking the relevant issue or confirming that no related issue exists.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly identifies the main change: applying the worker namespace suffix in shared sidecar argument parsing.

Full details: Description check

Explanation

The description explains the change and validation, but it does not follow the required template. It omits the Overview, Details, Where should the reviewer start?, and required Related Issues sections.

• Fix all pre-merge checks with AI

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[dynamo-review-agent]

Operator upgrade workloads can supply an already-suffixed DYN_NAMESPACE together with DYN_NAMESPACE_WORKER_SUFFIX (for example, default-qwen-decode-<hash> and <hash> in deploy/operator/internal/controller/upgrade_test.go). Applying this value parser unconditionally turns that into default-qwen-decode-<hash>-<hash>, while the controller's published runtime namespace remains suffixed once. Rust sidecars then register outside the namespace used for the active worker generation. Preserve an already-applied worker suffix, or have the caller provide an unambiguous base namespace before appending.

🤖 AI Fix

Append DYN_NAMESPACE_WORKER_SUFFIX only when the parsed namespace does not already end with the exact hyphen-delimited suffix, and add coverage for an already-suffixed DYN_NAMESPACE.

[tmonty12]

Already implemented in: #14955