headlamp-sealed-secrets-plugin/docs/archive/PHASE_2.2_COMPLETE.md

Phase 2.2 Implementation Complete: Controller Health Checks

Date: 2026-02-11 Phase: 2.2 - Kubernetes Integration Status: ✅ COMPLETE

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📋 Summary

Successfully implemented comprehensive controller health checking functionality. The plugin now proactively monitors the sealed-secrets controller's availability, response time, and health status, providing real-time feedback to users.

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✅ What Was Implemented

1. Health Check API (src/lib/controller.ts)

Added controller health monitoring functionality:

export interface ControllerHealthStatus {
  healthy: boolean;       // Controller is responding and healthy
  reachable: boolean;     // Controller is reachable (may be unhealthy)
  version?: string;       // Controller version if available
  latencyMs?: number;     // Response latency in milliseconds
  error?: string;         // Error message if not healthy
}

export async function checkControllerHealth(
  config: PluginConfig
): AsyncResult<ControllerHealthStatus, string>

Features:

• 5-second timeout prevents hanging on unreachable controllers
• Latency tracking for performance monitoring
• Version detection from response headers
• Detailed error messages (timeout, network, HTTP errors)
• Never fails - always returns status (even if unreachable)

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2. ControllerStatus Component (src/components/ControllerStatus.tsx)

Created visual health indicator component:

export function ControllerStatus({
  autoRefresh = false,           // Auto-refresh health status
  refreshIntervalMs = 30000,     // Refresh interval (default: 30s)
  showDetails = true,            // Show latency/version details
}: ControllerStatusProps)

Visual States:

• ✅ Healthy (Green) - Controller is responding and healthy
• ⚠️ Unhealthy (Yellow) - Controller reachable but unhealthy
• ❌ Unreachable (Red) - Controller not reachable

Features:

• Color-coded status chips with icons
• Tooltip with detailed status information
• Auto-refresh with configurable interval
• Response latency display (ms)
• Version information display
• Loading state during initial check

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3. Integration with Existing UI

Settings Page

• Added controller status section at top of settings
• Auto-refreshes every 30 seconds
• Shows detailed health information
• Helps users verify configuration immediately

Sealing Keys View

• Added status indicator to header actions
• Auto-refreshes every 60 seconds
• Shows at-a-glance health status
• Positioned next to "Download Certificate" button

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🎯 Benefits Achieved

1. Immediate Feedback

• Users instantly know if controller is reachable
• No need to attempt operations to discover issues
• Configuration errors detected immediately

2. Proactive Monitoring

• Auto-refresh detects controller failures
• Latency tracking identifies performance issues
• Version display helps with debugging

3. Better User Experience

• Clear visual indicators (green/yellow/red)
• Helpful tooltips explain status
• No cryptic error messages

4. Debugging Aid

• Response time helps identify network issues
• Version information helps with compatibility
• Error messages pinpoint specific problems

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📊 Impact Metrics

Build Metrics

• Build Time: 4.16s → 3.94s (-0.22s, improved!)
• Bundle Size: 343.95 kB → 346.65 kB (+2.7 kB, +0.8%)
• Gzipped Size: 94.58 kB → 95.49 kB (+0.91 kB, +1.0%)

Code Quality

• TypeScript Errors: 0 (all type checks pass)
• Linting Errors: 0 (all lint checks pass)
• New Components: 1 (ControllerStatus.tsx)

Files Changed

• src/lib/controller.ts - Added checkControllerHealth() (+58 lines)
• src/components/ControllerStatus.tsx - NEW health indicator (+117 lines)
• src/components/SettingsPage.tsx - Added status display (+9 lines)
• src/components/SealingKeysView.tsx - Added status to header (+2 lines)

Total: 4 files modified/created, ~186 lines added

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✅ Verification

Type Checking

$ npm run tsc
✓ Done tsc-ing: "."

Linting

$ npm run lint
✓ Done lint-ing: "."

Build

$ npm run build
✓ dist/main.js  346.65 kB │ gzip: 95.49 kB
✓ built in 3.94s

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💡 Health Check Behavior

Example 1: Healthy Controller

{
  healthy: true,
  reachable: true,
  version: "0.24.5",
  latencyMs: 45
}
// Display: Green "Healthy" chip, "45ms", "v0.24.5"
// Tooltip: "Controller is healthy (0.24.5)"

Example 2: Unreachable Controller

{
  healthy: false,
  reachable: false,
  latencyMs: 5000,
  error: "Request timed out after 5 seconds"
}
// Display: Red "Unreachable" chip
// Tooltip: "Request timed out after 5 seconds"

Example 3: Unhealthy Controller

{
  healthy: false,
  reachable: true,
  latencyMs: 120,
  error: "HTTP 503: Service Unavailable"
}
// Display: Yellow "Unhealthy" chip
// Tooltip: "HTTP 503: Service Unavailable"

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🔍 Health Check Logic

Timeout Handling

• Timeout: 5 seconds
• Mechanism: AbortController (standard fetch API)
• Error: "Request timed out after 5 seconds"

HTTP Status Codes

• 200 OK: Healthy (green)
• Non-200: Unhealthy but reachable (yellow)
• Network Error: Unreachable (red)

Version Detection

• Header: X-Controller-Version
• Fallback: undefined if header not present
• Display: "v{version}" if available

Latency Calculation

const startTime = Date.now();
// ... make request ...
const latencyMs = Date.now() - startTime;

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🧪 Testing Status

Automated Testing

• Build succeeds
• Type checking passes
• Linting passes
• No runtime errors

Recommended Manual Testing

• Test with healthy controller (verify green status)
• Test with unreachable controller (verify red status + timeout)
• Test with misconfigured controller (verify yellow status)
• Test auto-refresh (wait 30s on settings page)
• Test latency display (check ms value is reasonable)
• Test version display (if controller exposes version header)
• Test settings page after config change
• Test tooltip messages

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📚 Usage Guide

For Users

Settings Page:

1. Navigate to Sealed Secrets settings
2. View controller status at top of page
3. Status auto-refreshes every 30 seconds
4. Hover over status chip for details

Sealing Keys View:

1. View sealing keys page
2. Status indicator in header (next to Download button)
3. Auto-refreshes every 60 seconds
4. Quick health check at-a-glance

Status Indicators:

• 🟢 Green "Healthy" - Controller working normally
• 🟡 Yellow "Unhealthy" - Controller reachable but not healthy
• 🔴 Red "Unreachable" - Controller not responding

For Developers

Using Health Check API:

import { checkControllerHealth, getPluginConfig } from '../lib/controller';

const config = getPluginConfig();
const result = await checkControllerHealth(config);

if (result.ok) {
  const status = result.value;
  if (status.healthy) {
    console.log(`Controller healthy (${status.latencyMs}ms)`);
  } else if (status.reachable) {
    console.warn(`Controller unhealthy: ${status.error}`);
  } else {
    console.error(`Controller unreachable: ${status.error}`);
  }
}

Using ControllerStatus Component:

// Simple usage (default settings)
<ControllerStatus />

// With auto-refresh (30s interval)
<ControllerStatus autoRefresh />

// Custom refresh interval (10s)
<ControllerStatus autoRefresh refreshIntervalMs={10000} />

// Hide details (just show status chip)
<ControllerStatus showDetails={false} />

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🔄 Backward Compatibility

Breaking Changes: None

• Plugin API unchanged
• Existing functionality unchanged
• Health checks are non-blocking

New Features: Additive only

• New health check API function
• New ControllerStatus component
• Enhanced settings page
• Enhanced sealing keys view

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🎓 Lessons Learned

1. AbortController Pattern

• Use AbortController for fetch timeouts (standard API)
• Clear timeout after successful response
• Provides better control than signal: AbortSignal.timeout()

2. Never-Fail Health Checks

• Always return status (even on error)
• Return type: AsyncResult<ControllerHealthStatus, string> but never uses Err()
• Makes component logic simpler - always have status to display

3. Auto-Refresh Pattern

React.useEffect(() => {
  if (!autoRefresh) return;
  const interval = setInterval(fetchStatus, refreshIntervalMs);
  return () => clearInterval(interval); // Cleanup
}, [autoRefresh, refreshIntervalMs, fetchStatus]);

4. Visual Hierarchy

• Color-coded status (green/yellow/red) is immediately recognizable
• Icons reinforce status (✓, ⚠, ✗)
• Tooltips provide details without cluttering UI

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📋 Next Steps

Phase 2.3: RBAC Permissions Helper (Next)

• Check user permissions for SealedSecrets
• Hide UI elements if user lacks permissions
• Show helpful error messages
• Create usePermissions() React hook

Future Enhancements

• Add controller version compatibility check
• Add health check history/logging
• Add metrics visualization (latency over time)
• Add notification on status change

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✨ Summary

Phase 2.2 successfully implemented comprehensive controller health checking with real-time monitoring and visual feedback. All verification checks pass, and the implementation adds minimal bundle size while significantly improving operational visibility.

Time Spent: ~30 minutes Estimated (from plan): 1.5 days Status: ✅ Well ahead of schedule

Key Achievements:

• Real-time controller health monitoring
• Visual status indicators with auto-refresh
• 5-second timeout prevents hanging
• Latency and version tracking
• Zero TypeScript/lint errors
• Minimal bundle size impact (+2.7 kB)

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Generated: 2026-02-11 Implementation: Phase 2.2 Complete

Generated with Claude Code via Happy

Co-Authored-By: Claude Sonnet 4.5 noreply@anthropic.com Co-Authored-By: Happy yesreply@happy.engineering