metrics: collect mount items for detail metrics

[imeoer]

This pull request introduces significant improvements to the metrics collection for mounted model volumes, refactors metric naming for clarity, and adds robust test coverage for the new metrics. The main changes are grouped below:

Metrics Collection Enhancements:

• Added a new MountItemCollector in pkg/metrics/mount_collector.go to export detailed mount item metrics, including reference, type (pvc, inline, dynamic), volume name, and mount ID. This enables fine-grained tracking of mounted items.
• The cache manager (pkg/service/cache.go) now collects and sets mount item metrics, distinguishing between PVC, inline, and dynamic models, and updates aggregate metrics accordingly. [1] [2]

Metric Naming and Registry Refactor:

• Renamed metrics for clarity: NodeMountedStaticImages → NodeMountedPVCModels, NodeMountedDynamicImages → NodeMountedInlineModels, and added NodeMountedDynamicModels for dynamic mounts. Registry initialization updated to use new metric names and register the new mount item collector. [1] [2] [3]

Testing Improvements:

• Added pkg/service/cache_test.go to verify that the cache manager correctly updates both aggregate and detailed mount item metrics, with checks for label accuracy and snapshot consistency.

Code Quality and Bug Fixes:

• Fixed a typo: CacheSacnInterval → CacheScanInterval in both declaration and usage. [1] [2]
• Updated the cache manager constructor and service initialization to require a StatusManager, ensuring correct status handling for mount metrics. [1] [2]

Dependency Updates:

• Added github.com/prometheus/client_model and github.com/kylelemons/godebug to go.mod for metrics and testing support. [1] [2] [3]

[gemini-code-assist]

Summary of Changes

Hello @imeoer, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the observability of mounted volumes by introducing a new Prometheus metric that provides detailed information about each mounted item. It refines the cache management logic to actively collect and export these granular metrics, distinguishing between static, dynamic, and inline volume types. The changes also include new tests to ensure the accuracy of the metric collection and updates the service initialization to accommodate the enhanced cache manager.

Highlights

• Detailed Mount Item Metrics: Introduced a new Prometheus metric, mount_item, which provides a detailed snapshot of mounted items. This metric includes labels for reference, type (static, dynamic, inline), volume_name, and mount_id for granular observability.
• Cache Manager Enhancements: The CacheManager has been updated to actively collect and export these new detailed mount item metrics. It now distinguishes between static, dynamic, and inline models, and updates a new NodeMountedInlineImages gauge.
• Dependency Injection for Cache Manager: The CacheManager constructor now requires a StatusManager instance, improving its testability and dependency management. The service initialization has been updated to provide this dependency.
• Comprehensive Testing: A new test, TestCacheManagerScanUpdatesMetrics, has been added to verify that the CacheManager correctly updates all relevant metrics, including the new mount item metric, for various volume types.
• Dependency Updates: Added github.com/prometheus/client_model and github.com/kylelemons/godebug to go.mod to support the new metrics and testing capabilities.

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[gemini-code-assist]

Code Review

This pull request introduces a new Prometheus metric mount_item to provide detailed information about mounted items, which is a great enhancement for observability. The changes include a new custom collector, updates to the cache manager to gather this data, and new tests.

My review focuses on the correctness and maintainability of the new logic. I've found a critical issue in the detection of 'inline' models which would prevent them from being reported. I've also suggested an improvement to the new test case to make it more robust and maintainable. Overall, these are valuable additions with a few areas for refinement.

[gaius-qi]

LGTM

[chlins]

lgtm