DevContainer User
60 lines
2.6 KiB
Markdown
60 lines
2.6 KiB
Markdown
# ADR 002: Dual Data Fetching Strategy (Hooks + ApiProxy)
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**Status**: Accepted
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**Date**: 2026-03-05
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**Deciders**: Development Team
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---
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## Context
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The plugin needs data from two categories of Kubernetes resources:
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- **Standard resources**: Nodes and Pods, for which Headlamp provides reactive `useList()` hooks via built-in resource classes.
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- **Custom resources**: GpuDevicePlugin CRD (under `deviceplugin.intel.com/v1`) and DaemonSet pods with specific labels, for which Headlamp does not have built-in support.
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Headlamp provides reactive `useList()` hooks for standard resource classes but does not have built-in support for custom CRDs. The plugin uses three possible label selectors for DaemonSet pod discovery to handle different deployment configurations.
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---
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## Decision
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Implement a two-track data fetching strategy within the context provider:
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1. **Track 1 (Reactive)**: Use `K8s.ResourceClasses.Node.useList()` and `K8s.ResourceClasses.Pod.useList({namespace:''})` for standard resources. These are reactive to cluster changes and automatically update when resources are created, modified, or deleted.
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2. **Track 2 (Imperative)**: Use `ApiProxy.request()` inside a `useEffect` keyed on `refreshKey` for GpuDevicePlugin CRDs and DaemonSet pods. The `refreshKey` is incremented by the `refresh()` function exposed through the context.
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---
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## Consequences
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- ✅ Leverages Headlamp's reactive hooks for standard resources with automatic updates
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- ✅ Flexible `ApiProxy` for custom CRDs without needing to register custom resource classes
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- ✅ Refresh mechanism provides manual control over imperative fetches
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- ✅ Clean separation of reactive vs imperative data sources
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- ⚠️ Two different update mechanisms (hooks auto-update vs manual refresh for CRDs)
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- ⚠️ CRD data may lag behind hook data between refreshes
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The negative consequences are mitigated by providing a manual refresh button in the UI, allowing users to force an update of imperative data when needed.
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---
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## Alternatives Considered
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1. **All ApiProxy (no hooks)** — Rejected. Loses reactivity for standard resources, meaning Node and Pod changes would not be reflected until a manual refresh.
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2. **All hooks (register CRD as custom resource class)** — Rejected. Headlamp's `KubeObject` registration is complex for read-only CRD access and would add unnecessary coupling to Headlamp internals.
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3. **Single useEffect for everything** — Rejected. Loses the reactivity benefit for Nodes and Pods, and would require manual refresh for all data instead of just CRDs.
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---
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## Changelog
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| Date | Change |
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|------|--------|
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| 2026-03-05 | Initial decision accepted |
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