Mark-VIII/docs/specs/2026-08-24-ram-usage-card-design.md

Dashboard RAM Usage Card — Design Record

• Date: 2026-08-24
• Status: Approved (design review), implementation pending
• Scope: Mark VIII WebUI dashboard — add a RAM Usage status card between Disk Usage and Uptime, showing memory used / total in the same format as the Disk Usage card.

1. Goal

The dashboard (/ → Dashboard) currently shows status cards for Clients Connected, Handshakes Captured, Disk Usage, and Uptime. Add a RAM Usage card positioned after Disk Usage and before Uptime, displaying used / total (e.g. 120 MB / 256 MB) to match the Disk Usage card's presentation. The Pager is a ramips/mt76x8 device with 256 MB RAM.

2. Data source

The device's memory stats come from /proc/meminfo (available locally, since the webui server runs on the Pager):

• MemTotal — total RAM in kB
• MemAvailable — available RAM in kB (falls back to MemFree)

used = MemTotal - MemAvailable, matching how free reports usage on OpenWRT.

The health check already parses this file via _mem_percent() (server.py) but only exposes a percentage. The status endpoint has no memory field today.

3. Changes

Backend — payload/user/remote_access/pager-webui/server.py

• Add mem_data(): parse /proc/meminfo, return {'size': total_bytes, 'used': used_bytes, 'avail': avail_bytes} — the same shape as disk_data() (which returns {size, used, avail} in bytes). Return {} on parse failure, consistent with disk_data().
• Wire into status_data() as 'mem': mem_data().

Frontend — payload/user/remote_access/pager-webui/www/js/views.js

• Add ['mem', 'RAM Usage'] to the card defs array between ['disk', 'Disk Usage'] and ['uptime', 'Uptime'] (dashboard view).
• In the status update() handler, render fmtBytes(s.mem.used) + ' / ' + fmtBytes(s.mem.size); on missing data show Unavailable; in the initial-load catch path set —, mirroring the disk card's error handling.

Tests — tests/test_status.py

• Add mem_data() parse test using a temp fake /proc/meminfo file (the function takes an optional path argument, like battery_data(base)).
• Add mem to the h_status payload-shape key assertion.

4. Non-goals

• No memory graph/history — the Clients chart stays as is.
• No RAM percentage formatting on the card.
• No changes to the /api/health mem_percent metric.