cake-stats

cake-stats

Real-time web UI for monitoring CAKE SQM statistics on Linux and OpenWrt routers.

Built for embedded hardware where every allocation matters: Fiber v3 keeps HTTP overhead minimal, zerolog emits structured logs with near-zero allocations, and easyjson serves pre-generated serializers so the 100 ms poll loop never touches the GC hot path. The result is a single static binary that streams live per-tier CAKE stats to any browser with negligible CPU and memory cost.

Table of Contents

• How it looks like
  • Desktop
  • Mobile
• Status
• Features
• Requirements
• Design Notes
• Build
• Usage
• Limitations & Next Steps
• Contributing
• License

How it looks like

Desktop

UI for desktop screens

Graphs for desktop screens

Mobile

UI for mobile screens

Graphs for mobile screens

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Status

• Stable — all parser unit tests passing, binary builds clean for 14 target platforms. See Releases for the current version.

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Features

• Automatically discovers all CAKE qdiscs via tc -s qdisc
• Parses every CAKE field: thresh, target, interval, pk_delay, av_delay, sp_delay, backlog, pkts, bytes, way_inds, way_miss, way_cols, drops, marks, ack_drop, sp_flows, bk_flows, un_flows, max_len, quantum
• Correctly handles diffserv modes: diffserv3, diffserv4, diffserv8, besteffort, precedence; also parses the separate fwmark MASK tin-override parameter
• Two-word tier names are joined correctly (e.g. "Best Effort")
• Real-time push via Server-Sent Events — no WebSocket, no polling jitter
• Built on Fiber v3 with zerolog for structured logs and easyjson pre-generated serializers
• Default poll interval 100ms for near-instant UI updates (adjustable via -interval)
• Single static binary — no runtime dependencies
• Web UI: dark TUI aesthetic (#2D3C59 bg, JetBrains Mono, zero hover animations)
• Responsive for desktop and mobile (sticky first column, horizontal scroll on small screens)
• Per-interface live sparklines (TX throughput, avg latency, drops/s) with current-value labels
• Tap/click any sparkline bar to open a full-screen history modal with three uPlot time-series charts
• Server-side ring buffer retains history across page reloads (configurable via -history flag)

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Requirements

• Linux kernel with tc + sch_cake module loaded, or OpenWrt with kmod-sched-cake
• Go 1.25+ (build only; not needed at runtime)
• Third-party libraries used during build/services:
  • Fiber v3 – HTTP framework
  • zerolog – structured logging
  • easyjson – JSON code generation
  • rtnetlink – optional netlink client (not currently used; included in go.mod for future event‑based polling)

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Design Notes

• Modular architecture: code is split into pkg/parser, pkg/history, pkg/server, pkg/log, and pkg/types, with the CLI entrypoint under cmd/cake-stats. This keeps the core logic reusable and simplifies testing.
• Zero-allocation philosophy: hot paths avoid heap allocations by using sync.Pool for temporary buffers, easyjson-generated marshalers, and pre‑computed byte slices. Benchmark-driven optimisations ensure the 100 ms poll loop runs with minimal GC pressure.
• Ring buffer history: a thread-safe circular buffer stores past snapshots; clients receive both current data and historical samples after reconnects or page loads.
• Polling strategy: defaults to 100 ms for near-instant updates; interval is command-line configurable. The codebase contains scaffolding and a placeholder comment for an optional rtnetlink-based watcher, but the current release still relies on regular tc invocations.
• Server-Sent Events: statistics are broadcast over SSE. A pool of reusable message buffers reduces allocations when many clients connect.
• Fiber & zerolog: Fiber v3 provides a lightweight HTTP server with built‑in recovery middleware; zerolog supplies compact, structured log output.
• Single static binary: the project builds to one statically-linked executable, suitable for OpenWrt.
• Testing and documentation: parser and history packages include unit tests and benchmarks. Dependencies are kept to a minimum to ease audits.

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Build

git clone https://github.com/galpt/cake-stats
cd cake-stats
go test ./...          # should print PASS
# regenerate any easyjson helpers (optional)
go generate ./...
go build -ldflags "-s -w -X main.Version=1.0.0" -o cake-stats ./cmd/cake-stats

Cross-compile for a MIPS OpenWrt router:

CGO_ENABLED=0 GOOS=linux GOARCH=mips GOMIPS=softfloat \
  go build -ldflags "-s -w -X main.Version=1.0.0" -o cake-stats-linux-mips ./cmd/cake-stats

Pre-built binaries for all common platforms are attached to every GitHub Release.

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Usage

Quick start

./cake-stats                 # serves on http://0.0.0.0:11112
./cake-stats -port 8080      # custom port
./cake-stats -interval 2s    # poll tc every 2 seconds (default 100ms)
./cake-stats -history 3600   # retain 1 hour of history (default 300 = 5 min)
./cake-stats -host 127.0.0.1 # listen only on loopback
./cake-stats -version        # print version and exit

Open http://<router-ip>:11112 in a browser.

Install on OpenWrt

sh install.sh                # auto-detects arch, downloads latest binary
sh install.sh --port 11112 --interval 1s

Install on systemd Linux

sudo sh install.sh

Uninstall

sh uninstall.sh              # prompts for confirmation
sh uninstall.sh --force      # no prompts

API

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Limitations & Next Steps

• Still polls using tc; a kernel‑level rtnetlink watcher is included as an option but not yet the default.
• No built‑in authentication or HTTPS; expose only on trusted networks or pair with a reverse proxy.
• UI is intentionally minimal.
• RAM footprint may vary. Depending on kernel malloc behaviour, architecture and how many clients are connected the value can be anywhere from about 4 MB up to a dozen megabytes.
• Cross‑platform builds are produced, but CAKE itself is Linux‑only; Windows/FreeBSD binaries do not collect real data.

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Contributing

go test ./...    # run unit tests
go vet ./...     # static analysis

PRs welcome. Please keep external dependencies at zero.

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License

MIT

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