Initial Beach: homelab control panel

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

internal/beach/host_linux.go

@@ -0,0 +1,53 @@
+//go:build linux
+
+package beach
+
+import (
+	"os"
+	"runtime"
+	"sync"
+	"syscall"
+	"time"
+)
+
+var (
+	cpuMu   sync.Mutex
+	lastCPU cpuTimes
+	lastAt  time.Time
+	lastPct float64
+)
+
+func readFile(p string) string { b, _ := os.ReadFile(p); return string(b) }
+
+// CollectHost reads /proc. CPU use is the change since the previous call; the
+// first call takes a short sample of its own.
+func CollectHost() Host {
+	h := Host{Supported: true, CPUs: runtime.NumCPU(), Disks: []Filesystem{}}
+	h.Hostname, _ = os.Hostname()
+	h.Uptime = parseUptime(readFile("/proc/uptime"))
+	h.Load = parseLoad(readFile("/proc/loadavg"))
+	h.MemTotal, h.MemUsed, h.SwapTotal, h.SwapUsed = parseMeminfo(readFile("/proc/meminfo"))
+	cpuMu.Lock()
+	if now, err := parseCPU(readFile("/proc/stat")); err == nil {
+		if lastAt.IsZero() {
+			time.Sleep(250 * time.Millisecond)
+			if n2, err := parseCPU(readFile("/proc/stat")); err == nil {
+				lastPct, now = cpuPct(now, n2), n2
+			}
+			lastCPU, lastAt = now, time.Now()
+		} else if time.Since(lastAt) > 500*time.Millisecond {
+			lastPct = cpuPct(lastCPU, now)
+			lastCPU, lastAt = now, time.Now()
+		}
+	}
+	h.CPUPct = lastPct
+	cpuMu.Unlock()
+	for _, m := range realMounts(readFile("/proc/mounts")) {
+		var st syscall.Statfs_t
+		if syscall.Statfs(m, &st) == nil && st.Blocks > 0 {
+			bs := uint64(st.Bsize)
+			h.Disks = append(h.Disks, Filesystem{Mount: m, Total: st.Blocks * bs, Used: (st.Blocks - st.Bfree) * bs})
+		}
+	}
+	return h
+}