fix(container-cache): honor pod disruption budget values

[rohancmr]

TL;DR

Make the container-cache PodDisruptionBudget honor its documented Helm values. The chart now gates the resource on enabled, supports either availability field, and retains the existing 50% fallback.

Additional Details

The existing template created a PodDisruptionBudget whenever replicaCount was greater than one. It ignored podDisruptionBudget.enabled, minAvailable, and maxUnavailable.

This change:

• Gates the resource on podDisruptionBudget.enabled.
• Renders the configured minAvailable or maxUnavailable value.
• Retains minAvailable: 50% when neither field is configured.
• Rejects configurations that set both availability fields.
• Preserves integer values such as minAvailable: 0.
• Adds focused render regression coverage.

Existing installations that relied on the implicit PDB for multiple replicas must set podDisruptionBudget.enabled: true.

For the Reviewer

Review the PDB value selection and validation in templates/poddisruptionbudget.yaml and the render cases in tests/render-pdb-test.sh.

For QA

Validated with:

• bash deploy/helm/container-cache/tests/render-pdb-test.sh
• helm lint deploy/helm/container-cache/deploy
• bash deploy/helm/container-cache/tests/render-apiversion-test.sh
• Existing container-cache render tests
• Structural Helm comparisons against origin/main
• bash -n deploy/helm/container-cache/tests/render-pdb-test.sh
• git diff --check

QA is not needed beyond chart rendering.

Issues

Fixes #1617

Checklist

• I am familiar with the Contributing Guidelines.
• I have signed off my commits for Developer Certificate of Origin (DCO) compliance.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

Summary by CodeRabbit

• New Features

  • Added configurable PodDisruptionBudget support controlled by an enablement setting.
  • Supports either minimum available or maximum unavailable settings.
  • Defaults minimum availability to 50% when no availability value is provided.
  • Preserves configured availability values and safely handles empty or null settings.
  • Validates configurations to prevent both availability settings from being used simultaneously.

• Tests

  • Added coverage for enabled, disabled, default, zero-value, resource-count, null-value, and invalid configurations.

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📥 Commits

Reviewing files that changed from the base of the PR and between 9d7384b and a3afbff.

📒 Files selected for processing (2)

• deploy/helm/container-cache/deploy/templates/poddisruptionbudget.yaml
• deploy/helm/container-cache/tests/render-pdb-test.sh

🚧 Files skipped from review as they are similar to previous changes (2)

• deploy/helm/container-cache/tests/render-pdb-test.sh
• deploy/helm/container-cache/deploy/templates/poddisruptionbudget.yaml

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📝 Walkthrough

Walkthrough

The Helm chart now preserves PodDisruptionBudget availability values, handles null and zero values, rejects simultaneous minAvailable and maxUnavailable, and documents the 50% fallback. A Bash test covers these configurations.

Changes

PodDisruptionBudget configuration

Layer / File(s)	Summary
PodDisruptionBudget value selection deploy/helm/container-cache/deploy/templates/poddisruptionbudget.yaml, deploy/helm/container-cache/deploy/values.yaml	The template uses nil-safe presence checks, preserves configured availability values, rejects both fields, and defaults to minAvailable: 50%. The values documentation describes the mutual exclusion and fallback behavior.
Rendering validation deploy/helm/container-cache/tests/render-pdb-test.sh	The test covers default, disabled, explicit, null, zero, fallback, resource-count, and mutually exclusive configurations.

Priority: ➖ Normal

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

Change: Bug fix · Severity of issue fixed: Medium

Merge Risk: ⚪ Minimal · up to a3afb

The configurable PDB rendering behavior is covered for the documented settings, including disabled, fallback, null, zero, and conflicting values. No actionable merge risk remains.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 5 functions across 1 files. (1 skipped: 1 …	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title uses the required Conventional Commits format with the customer-impact type "fix" and scope "container-cache". It accurately describes the PodDisruptionBudget behavior change.
Linked Issues check	✅ Passed	Issue #1617 requires PDB gating, configurable availability fields, and a 50% fallback. The template renders a PDB only when podDisruptionBudget.enabled is true. It emits the configured `minAvailable…
Out of Scope Changes check	✅ Passed	The changes remain within Issue #1617 scope. The values comment documents the fallback, and the render tests verify the required PDB behavior. No unrelated product behavior is identified.

Full details: Docstring Coverage

Explanation

Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 5 functions across 1 files. (1 skipped: 1 unsupported.)

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[coderabbitai]

Actionable comments posted: 1

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Inline comments:
In `@deploy/helm/container-cache/deploy/templates/poddisruptionbudget.yaml`:
- Around line 16-17: Update the pod disruption budget value handling around
$pdbMinAvailable and $pdbMaxUnavailable to treat nil values as unset before
converting or validating them. Preserve explicit numeric 0 as configured, retain
the documented minAvailable: 50% fallback when minAvailable is null, and avoid
the mutual-exclusion error when both availability values are null.

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Configuration used: Path: .coderabbit.yaml

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📥 Commits

Reviewing files that changed from the base of the PR and between bf4cddf and 9d7384b.

📒 Files selected for processing (3)

• deploy/helm/container-cache/deploy/templates/poddisruptionbudget.yaml
• deploy/helm/container-cache/deploy/values.yaml
• deploy/helm/container-cache/tests/render-pdb-test.sh

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[balajinvda]

🎉 This PR is included in deploy/helm/container-cache/v0.30.5 🎉

The release is available on GitHub release

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