fix: use legacy metrics exporter images

[brendan-kellam]

Summary

• override the bundled PostgreSQL metrics exporter repository to use Bitnami Legacy
• override the bundled Redis metrics exporter repository to use Bitnami Legacy
• document both values and add dependency-level rendering tests

Context

The primary PostgreSQL and Valkey images already use the bitnamilegacy namespace, but their optional metrics sidecars still inherited bitnami/postgres-exporter and bitnami/redis-exporter from the pinned subcharts. Those versioned tags are no longer available in the original namespace, causing ImagePullBackOff whenever metrics are enabled and a node must pull the image again.

Test plan

• helm lint ./charts/sourcebot -f ./charts/sourcebot/values.lint.yaml
• helm unittest charts/sourcebot --color
• helm template with postgresql.metrics.enabled=true and redis.metrics.enabled=true

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Note

Low Risk
Default image repository overrides for optional metrics sidecars only; no auth, data, or Sourcebot app behavior changes.

Overview
Fixes ImagePullBackOff when bundled PostgreSQL or Redis metrics are enabled: optional exporter sidecars were still pulling from the default bitnami/* repos while the main database images already use bitnamilegacy.

The chart now defaults postgresql.metrics.image.repository to bitnamilegacy/postgres-exporter and redis.metrics.image.repository to bitnamilegacy/redis-exporter, with README values table updates and helm-unittest coverage that asserts the rendered sidecar images when metrics are turned on. The unreleased changelog records the fix.

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Summary by CodeRabbit

• Bug Fixes

  • Updated PostgreSQL and Redis metrics exporters to use Bitnami Legacy images when enabled.
  • Prevents metrics exporter image configuration from relying on unavailable or paid repositories.

• Documentation

  • Added configuration guidance for selecting the PostgreSQL and Redis/Valkey metrics exporter images.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Team

Run ID: 8e6d02d6-044d-4274-b2ad-797c86f68730

📥 Commits

Reviewing files that changed from the base of the PR and between 4b89b96 and 796181c.

📒 Files selected for processing (5)

• CHANGELOG.md
• charts/sourcebot/README.md
• charts/sourcebot/tests/postgresql_metrics_image_test.yaml
• charts/sourcebot/tests/redis_metrics_image_test.yaml
• charts/sourcebot/values.yaml

Included review availability: Your plan provides up to 1 included review per hour; 0 remain after this review.

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Walkthrough

The Helm chart configures Bitnami Legacy repositories for PostgreSQL and Redis metrics exporters. New Helm tests verify the rendered exporter images. The changelog and chart README document the change.

Changes

Metrics exporter images

Layer / File(s)	Summary
Exporter image configuration charts/sourcebot/values.yaml, charts/sourcebot/README.md, CHANGELOG.md	The chart sets Bitnami Legacy repositories for PostgreSQL and Redis metrics exporters. The README and changelog document the defaults.
Exporter image validation charts/sourcebot/tests/*metrics_image_test.yaml	Helm tests enable metrics and verify the rendered PostgreSQL and Redis exporter image references.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Merge Risk: ⚪ Minimal · up to 79618

This updates the bundled PostgreSQL and Redis metrics exporters to available Bitnami Legacy images and verifies the rendered image references when metrics are enabled. The documented defaults and tests are aligned, with no current merge-readiness risk identified.

Suggested reviewers: msukkari

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely summarizes the main change: using Bitnami Legacy images for the PostgreSQL and Redis metrics exporters.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…
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.

Full details: Docstring Coverage

Explanation

No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0 files. (5 skipped: 5 unsupported.)

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/legacy-metrics-exporter-images

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[github-actions]

Helm Unit Test Results

20 tests  +2   20 ✅ +2   0s ⏱️ ±0s
 3 suites +2    0 💤 ±0 
 1 files   ±0    0 ❌ ±0 

Results for commit 796181c. ± Comparison against base commit 4b89b96.