feat(watch): add localized system stats to watch dashboard

[utkarsh232005]

Closes #117

Description

This PR introduces system resource stats (CPU and Memory) directly into the kdm watch dashboard:

• Docker Section: Aggregates CPU % and Memory usage dynamically across running containers, complying with cgroups v1 & v2.
• Kubernetes Section: Queries metrics-server nodes/pods dynamically, with a fallback to native resource requests sum.
• Includes thorough JSDoc documentation and unit testing coverage.

Summary by CodeRabbit

• New Features

  • Dashboard now displays Kubernetes cluster-level CPU and memory statistics with source attribution (metrics-server, requests, or N/A).
  • Added Docker system resource stats including total CPU percentage and memory usage/limits visible on the dashboard.
  • Stats automatically refresh every 3 seconds for real-time updates.

• Tests

  • Comprehensive test suite for stats utilities covering CPU/memory parsing, formatting, and aggregation scenarios.

[coderabbitai]

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ℹ️ Review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 3a8ad70 and aa2a9eb.

📒 Files selected for processing (5)

• src/__tests__/stats.test.ts
• src/__tests__/watch-dashboard.test.tsx
• src/docker/containers.ts
• src/kubernetes/pods.ts
• src/server/server.ts

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📝 Walkthrough

Walkthrough

This PR adds system-level resource monitoring to kdm watch, collecting Docker aggregate stats via the Docker API and Kubernetes cluster stats via metrics-server (with native requests fallback), then displaying both in separate dashboard panels with 3-second polling intervals.

Changes

System Stats Dashboard Integration

Layer / File(s)	Summary
Docker system stats aggregation src/docker/containers.ts	DockerSystemStats interface and getDockerSystemStats() export aggregate CPU percentage and memory usage/limit across running containers, with byte formatter and per-container helpers to compute CPU deltas and memory net of cache.
Kubernetes cluster stats module src/kubernetes/pods.ts	K8sClusterStats interface and getK8sClusterStats() export with parsing utilities for Kubernetes CPU/memory quantities. Aggregation prioritizes metrics-server node stats, falls back to pod stats, then native pod resource requests, and returns N/A when all sources fail.
Dashboard UI integration src/ui/WatchDashboard.tsx	Component adds k8sStats and dockerStats state, imports both fetcher functions, extends polling loop to refresh stats every 3 seconds, and renders CPU/memory values in separate Kubernetes and Docker panels with null fallback.
Test suite src/__tests__/stats.test.ts	Comprehensive Vitest suite mocks Docker and Kubernetes APIs and validates quantity parsing, byte formatting across binary and decimal units, Docker stats aggregation, and Kubernetes multi-source fallback behavior.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Poem

🐰 Stats now bloom in kdm's display,
Docker and Kubernetes at play,
CPU, memory—watch them dance,
Three-second heartbeat; metrics prance,
No more jumping out to see the load!

🚥 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 summarizes the main change: adding system stats display to the watch dashboard, which is the central objective across all file modifications.
Linked Issues check	✅ Passed	The PR implements all core requirements from issue #117: Docker stats (CPU %, memory), Kubernetes stats (metrics-server with fallback to requests), graceful degradation, and reasonable update intervals (3 seconds).
Out of Scope Changes check	✅ Passed	All changes are directly related to implementing system stats for Docker and Kubernetes sections as specified in issue #117; no unrelated modifications detected.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[codecov]

Codecov Report

❌ Patch coverage is 88.64865% with 21 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/docker/containers.ts	82.69%	1 Missing and 8 partials ⚠️
src/kubernetes/pods.ts	91.66%	0 Missing and 9 partials ⚠️
src/ui/WatchDashboard.tsx	85.71%	0 Missing and 3 partials ⚠️

📢 Thoughts on this report? Let us know!

[coderabbitai]

Actionable comments posted: 4

🧹 Nitpick comments (1)

src/docker/containers.ts (1)

125-137: ⚡ Quick win

Consider logging errors for debugging visibility.

The catch block silently swallows errors when fetching container stats. While returning zero values is appropriate for graceful degradation, logging the error (at least at debug level) would help diagnose issues when containers fail to report stats.

🔍 Proposed enhancement

   } catch {
+    logger.debug(`Failed to fetch stats for container ${containerId}`);
     return { cpuPercent: 0, memoryUsage: 0, limit: 0 };
   }

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@src/docker/containers.ts` around lines 125 - 137, The fetchContainerStats
function swallows errors silently; update the catch to capture the error (catch
(err)) and log it for visibility before returning zeros—use the module logger if
available (e.g., processLogger.debug or logger.debug), otherwise fall back to
console.debug/console.error; keep the existing return { cpuPercent: 0,
memoryUsage: 0, limit: 0 } for graceful degradation.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@src/docker/containers.ts`:
- Around line 143-180: getDockerSystemStats currently uses the maximum
per-container limit (computed from results of fetchContainerStats) as
memoryLimit which misrepresents aggregate host capacity; change it to always
call docker.info() to obtain MemTotal and use that as memoryLimit (with a safe
fallback like 0) regardless of container limits, remove the maxLimit logic that
picks the largest container limit, and ensure the docker.info() call is awaited
and error-handled before returning the final { cpu, memoryUsage, memoryLimit }
in getDockerSystemStats.

In `@src/kubernetes/pods.ts`:
- Around line 78-97: The function parseK8sCpuQuantity currently treats any
unknown non-empty suffix as cores; update it so only the known suffixes
('n','u','m','' for cores) map to conversions and all other suffixes return 0.
In practice, modify the switch in parseK8sCpuQuantity to keep cases
'n','u','m','' as-is and change the default branch to return 0 (i.e., do not
multiply unknown suffixes by 1000), so malformed inputs like '100x' yield 0
instead of being treated as cores.
- Around line 211-223: The sumPodRequests function incorrectly adds init
container requests to app container requests; change it to only sum requests
from pod.spec?.containers (exclude pod.spec?.initContainers) so
sumPodRequests(pod) uses getContainerRequests only for app containers, leaving
init containers out of the native-fallback estimate (this keeps Running pods
correct and is conservative for Pending pods).
- Around line 104-135: In parseK8sMemoryQuantity, currently unknown suffixes
fall through to being treated as raw bytes; change the logic to return 0 when a
non-empty, unrecognized suffix is present. Specifically, inside function
parseK8sMemoryQuantity after extracting suffix, allow empty suffixes to be
treated as bytes (return val), handle known binaryPower (Ki/Mi/...) and
decimalPower (k/M/...) as before, and if suffix is non-empty and not found in
either map return 0; update references to suffix and the
binaryPower/decimalPower checks accordingly.

---

Nitpick comments:
In `@src/docker/containers.ts`:
- Around line 125-137: The fetchContainerStats function swallows errors
silently; update the catch to capture the error (catch (err)) and log it for
visibility before returning zeros—use the module logger if available (e.g.,
processLogger.debug or logger.debug), otherwise fall back to
console.debug/console.error; keep the existing return { cpuPercent: 0,
memoryUsage: 0, limit: 0 } for graceful degradation.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 61b8acc2-08e3-42ec-bf00-1fa5ee0f2289

📥 Commits

Reviewing files that changed from the base of the PR and between 48898f3 and 3a8ad70.

📒 Files selected for processing (4)

• src/__tests__/stats.test.ts
• src/docker/containers.ts
• src/kubernetes/pods.ts
• src/ui/WatchDashboard.tsx

[codescene-delta-analysis]

Code Health Improved (1 files improve in Code Health)

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Gates Passed
3 Quality Gates Passed

View Improvements

File	Code Health Impact	Categories Improved
WatchDashboard.tsx	9.55 → 10.00	Complex Method

Quality Gate Profile: The Bare Minimum
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