Files
Varaverk/Plugin/unraid/api/monitor_fast.php
T
Gmer4Lfe 987313e7dc Document the PHP api layer and fix what documenting it exposed
Writing down what each endpoint actually guarantees made the places it
didn't obvious — shell arguments reaching a crontab or a bash -c
unescaped, master.conf written without tmp+rename, and conf edits that
could be saved without ever being parsed.
2026-08-02 10:11:39 -04:00

120 lines
5.9 KiB
PHP

<?php
// ═══════════════════════════════════════════════════════════════════════════════════════════════
// PURPOSE
// High-frequency monitor poll. CPU, memory and network only, cheap enough to fetch every
// second — the live-updating subset of what monitor.php returns in full.
//
// OPERATIONAL MODEL
// Split from monitor.php on refresh rate. The fields here move second to second and are
// readable from /proc alone. Everything that needs `docker stats`, a GraphQL call, or an
// SSH round trip stays in the full payload, because those cannot be sampled at this rate.
//
// The expensive memory breakdown is borrowed rather than recomputed. Docker and VM memory,
// top processes and swap come from the last full cache — a 600s window, wide enough that
// the card stays populated even when the background writer falls behind. Stale is the right
// trade here: per-container memory does not move meaningfully between seconds, and paying
// for it would defeat the point of this endpoint.
//
// DESIGN PRINCIPLES
// Reads /proc directly, no shell.
// /proc/meminfo and the ZFS arcstats file are parsed inline. At this poll rate a single
// fork per request would dominate the cost of the endpoint.
//
// Shares the CPU baseline with everything else.
// vv_cpu_per_core() keeps its counters in a shared state file, so this endpoint, the
// header snapshot, and the full monitor payload all report the same number rather than
// three independent samples that visibly disagree.
//
// Free means available, not unused.
// MemAvailable, not MemFree — reclaimable page cache is not memory pressure, and
// reporting MemFree would show a healthy machine as nearly full.
//
// ZFS ARC is broken out of system memory.
// On a host with ZFS cache pools the ARC is most of the "used" figure and is fully
// reclaimable. Folding it into system memory would make every reading alarming and
// none of them actionable.
//
// OPERATIONAL SAFEGUARDS
// Read-only.
//
// Every source read has a fallback.
// file() with a ?: [] fallback, @file() for the arcstats path that does not exist on a
// host without ZFS, and ?? 0 on every extracted key. A missing subsystem contributes
// zero rather than a warning or a fatal — and at one request per second, a fatal here
// would be a page that never stops erroring.
//
// The borrowed fields degrade to zero independently.
// Each ?? default is applied per field, so an absent or expired full cache costs those
// four values and leaves CPU, memory and network — the reason to call this endpoint —
// intact.
//
// Swap has its own fallback path.
// When the cached figures are absent, swap is recomputed from /proc/meminfo rather than
// reported as zero, because zero swap used and unknown swap used look identical in the
// UI and mean very different things.
//
// Derived values are clamped.
// max(0, …) on used and system memory, so the subtraction cannot go negative when the
// cached docker and VM figures were sampled against a different total.
//
// REQUEST
// GET, no parameters
//
// RESPONSE
// {"cpu":{…},"mem":{total_kb,free_kb,used_kb,arc_kb,docker_kb,vm_kb,system_kb,
// swap_total_kb,swap_used_kb,top_procs},"net":{…},"ts":epoch}
//
// DEPENDS ON
// include/config.php vv_cache_read()
// include/common.php vv_cpu_per_core(), vv_network_stats()
// /proc/meminfo, /proc/spl/kstat/zfs/arcstats
// monitor cache written by Tools/api_cache_writer.sh — source of the borrowed fields
// ═══════════════════════════════════════════════════════════════════════════════════════════════
header('Content-Type: application/json');
require_once dirname(__DIR__) . '/include/config.php';
require_once dirname(__DIR__) . '/include/common.php';
// Pull slow fields (docker/vm/top_procs/swap) from last full cache — stale is fine,
// these don't change on a per-second basis. 600s window so the card stays populated
// even if the full cache writer is temporarily behind.
$_full = vv_cache_read('monitor', 600);
$_dockerKb = $_full['mem']['docker_kb'] ?? 0;
$_vmKb = $_full['mem']['vm_kb'] ?? 0;
$_topProcs = $_full['mem']['top_procs'] ?? [];
$_swapTotal = $_full['mem']['swap_total_kb'] ?? 0;
$_swapUsed = $_full['mem']['swap_used_kb'] ?? 0;
// Fast memory: /proc/meminfo + ZFS ARC (no docker stats, no GQL)
$_memRaw = [];
foreach (file('/proc/meminfo') ?: [] as $_l) {
if (preg_match('/^(\w+):\s+(\d+)/', $_l, $_m)) $_memRaw[$_m[1]] = (int)$_m[2];
}
$_totalKb = $_memRaw['MemTotal'] ?? 0;
$_freeKb = $_memRaw['MemAvailable'] ?? 0;
$_arcKb = 0;
foreach (@file('/proc/spl/kstat/zfs/arcstats') ?: [] as $_l) {
if (preg_match('/^size\s+\d+\s+(\d+)/', $_l, $_m)) { $_arcKb = (int)($_m[1] / 1024); break; }
}
if (!$_swapTotal) {
$_swapTotal = $_memRaw['SwapTotal'] ?? 0;
$_swapUsed = max(0, ($_memRaw['SwapTotal'] ?? 0) - ($_memRaw['SwapFree'] ?? 0));
}
echo json_encode([
'cpu' => vv_cpu_per_core(),
'mem' => [
'total_kb' => $_totalKb,
'free_kb' => $_freeKb,
'used_kb' => max(0, $_totalKb - $_freeKb),
'arc_kb' => $_arcKb,
'docker_kb' => $_dockerKb,
'vm_kb' => $_vmKb,
'system_kb' => max(0, $_totalKb - $_freeKb - $_arcKb - $_dockerKb - $_vmKb),
'swap_total_kb' => $_swapTotal,
'swap_used_kb' => $_swapUsed,
'top_procs' => $_topProcs,
],
'net' => vv_network_stats(),
'ts' => time(),
]);