Expose container block I/O counters in stats (utilization.disk_io)

[flxmrk]

What

Adds cumulative container block-I/O counters to the stats payload:

"utilization": {
  "network": { "rx_bytes": 27353515, "tx_bytes": 132234063 },
  "disk_io": { "read_bytes": 0, "write_bytes": 81649664 }
}

Why

Docker's stats stream (which pollResources already consumes) carries the cgroup block-I/O counters, but wings currently drops them. Surfacing them lets panels and API consumers show per-server disk throughput exactly the way they already derive network rates — deltas between readings of a cumulative counter. Disk I/O is often the first thing saturating a node packed with game servers (world autosaves, chunk generation, steamcmd updates), and today there's no per-server visibility into it.

How

+24 lines, additive only — mirrors the existing NetworkStats shape:

• environment/stats.go: new DiskIoStats{read_bytes, write_bytes} on Stats as disk_io
• environment/docker/stats.go: sum BlkioStats.IoServiceBytesRecursive into it; ops matched case-insensitively since cgroup v1 reports Read/Write while v2 (io.stat) reports read/write
• server/resources.go: zero the counters in Reset()

Existing consumers are unaffected (unknown JSON fields are ignored by the panel).

Testing

Running in production on a live node (built from v1.0.0-beta26 + this patch, cgroup v2, Docker 28). Counters verified against real workloads: a forced Palworld world save moved write_bytes by ~47 MB in one reading; steamcmd install traffic and zero-read steady state (fully page-cached world) both report as expected. Websocket stats events carry the field as well since they serialize the same struct.

Summary by CodeRabbit

• New Features

  • Added cumulative disk I/O metrics to resource usage data, including read and write byte totals.

• Bug Fixes

  • Disk I/O counters now reset correctly when resource usage is reset, preventing stale values from carrying over.

[coderabbitai]

📝 Walkthrough

Walkthrough

Docker statistics now expose cumulative disk read/write bytes, populate them from Docker block I/O data, and clear them when resource usage resets.

Changes

Disk I/O statistics

Layer / File(s)	Summary
Disk I/O data contract and collection environment/stats.go, environment/docker/stats.go	Adds JSON-serialized disk read/write counters and accumulates Docker block I/O entries using case-insensitive operation matching.
Disk I/O reset handling server/resources.go	Resets disk read and write counters alongside existing resource usage values.

Estimated code review effort: 2 (Simple) | ~10 minutes

Poem

I’m a rabbit counting bytes in a burrow so bright,
Read hops by day and write hops by night.
Docker brings counters, neatly in line,
Reset clears the slate when the server resigns.
Carrots for stats—what a wonderful design!

🚥 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: exposing container block I/O counters in stats under utilization.disk_io.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

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[coderabbitai]

🧹 Nitpick comments (2)

server/resources.go (1)

71-72: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Add a reset regression test for the new counters.

Initialize nonzero disk counters, call ResourceUsage.Reset, and verify both values return to zero.

🤖 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 `@server/resources.go` around lines 71 - 72, Add a regression test for
ResourceUsage.Reset that initializes DiskIo.ReadBytes and DiskIo.WriteBytes to
nonzero values, invokes Reset, and asserts both counters are reset to zero.

environment/docker/stats.go (1)

94-103: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Add regression coverage for operation casing and aggregation.

Test both Read/Write and read/write entries, including multiple device entries, and assert the resulting disk_io.read_bytes and disk_io.write_bytes totals.

🤖 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 `@environment/docker/stats.go` around lines 94 - 103, Add regression coverage
for the Docker block I/O aggregation handled in the stats collection path:
provide both uppercase “Read”/“Write” and lowercase “read”/“write” operations
across multiple device entries, then assert that disk_io.read_bytes and
disk_io.write_bytes contain the summed totals.

🤖 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.

Nitpick comments:
In `@environment/docker/stats.go`:
- Around line 94-103: Add regression coverage for the Docker block I/O
aggregation handled in the stats collection path: provide both uppercase
“Read”/“Write” and lowercase “read”/“write” operations across multiple device
entries, then assert that disk_io.read_bytes and disk_io.write_bytes contain the
summed totals.

In `@server/resources.go`:
- Around line 71-72: Add a regression test for ResourceUsage.Reset that
initializes DiskIo.ReadBytes and DiskIo.WriteBytes to nonzero values, invokes
Reset, and asserts both counters are reset to zero.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 413b4f12-c9ea-47a5-a5d1-6aa57bf8cea0

📥 Commits

Reviewing files that changed from the base of the PR and between 1c2070e and 61352fe.

📒 Files selected for processing (3)

• environment/docker/stats.go
• environment/stats.go
• server/resources.go

📜 Review details

🧰 Additional context used

🧠 Learnings (1)

📚 Learning: 2026-03-02T13:53:08.995Z

Learnt from: parkervcp
Repo: pelican-dev/wings PR: 171
File: server/power.go:190-203
Timestamp: 2026-03-02T13:53:08.995Z
Learning: In the server package, when quotas are enabled via config.Get().System.Quotas.Enabled, the disk space check using used >= s.DiskSpace() does not require a special guard for unlimited-disk scenarios (DiskSpace() <= 0). The filesystem handles such cases, so the existing check is sufficient. Apply this pattern to similar quota-related disk checks in the server package and ensure tests/docs reflect that unlimited-disk behavior is governed by the filesystem, not by an extra guard in code.

Applied to files:

• server/resources.go

🔇 Additional comments (2)

environment/stats.go (1)

23-27: LGTM!

Also applies to: 36-40

environment/docker/stats.go (1)

7-7: LGTM!