feat: search exact tag match avoiding pagination

[raelga]

Summary

Adds two improvements to the image-updater:

1. Direct tag lookup - Fetch specific tags without pagination (performance)
2. Version label extraction - Show commit hashes/versions instead of generic tag names (usability)

Changes

1. Direct Tag Lookup (Avoid Pagination)

Added tag field as an alternative to tagPattern for fetching specific tags directly:

# Before: Paginate through all tags (slow)
tagPattern: "^v1\\.18\\.3$"

# After: Direct lookup (fast, single API call)
tag: "v1.18.3"

Benefits:

• No pagination required
• Single API call vs multiple pages
• Faster execution for pinned versions and generic tags like "latest"

Use cases:

• Pinning during rollbacks: tag: "v1.18.3"
• Using generic tags efficiently: tag: "latest"
• Testing specific releases: tag: "rc-2.0.0"

2. Version Label Extraction

Added versionLabel field to extract version info from container labels:

source:
  tag: "latest"
  versionLabel: "org.opencontainers.image.revision"  # Default when using 'tag'

Output:

# Before
digest: sha256:abc123... # latest (2025-11-24 14:30)

# After  
digest: sha256:abc123... # a1b2c3d4e5f6 (2025-11-24 14:30)

Defaults:

• tag field: extracts org.opencontainers.image.revision by default
• tagPattern field: uses tag name (no label extraction)

Code optimizations:

• Created helper functions, reduced ~150 lines of duplicated code
• No extra network calls for Generic/Quay clients
• Graceful fallback to tag name if label not found

Configuration

Field	Description	Default
tag	Exact tag (no pagination)	-
tagPattern	Regex pattern (requires pagination)	-
versionLabel	Container label to extract	org.opencontainers.image.revision (with tag), empty (with tagPattern)

Note: tag and tagPattern are mutually exclusive

Example

images:
  hypershift:
    source:
      tag: "latest"  # Direct lookup + version label extraction
      versionLabel: "org.opencontainers.image.revision"

  pko-manager:
    source:
      tag: "v1.18.3"  # Direct lookup for pinned version

  pko-package:
    source:
      tagPattern: "^v\\d+\\.\\d+\\.\\d+$"  # Auto-update latest matching

[sclarkso]

/lgtm

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: raelga, sclarkso

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Details

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• tooling/image-updater/OWNERS [raelga]

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[raelga]

/test e2e-parallel

[raelga]

/test e2e-parallel

[raelga]

/test e2e-parallel

[openshift-ci-robot]

/retest-required

Remaining retests: 0 against base HEAD 4db1389 and 2 for PR HEAD 77b7338 in total