Initial Beach: homelab control panel

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

internal/beach/smart.go

@@ -0,0 +1,85 @@
+package beach
+
+import (
+	"context"
+	"encoding/json"
+	"os/exec"
+	"sort"
+	"time"
+)
+
+// parseSmartctl reads `smartctl -j -H -i -A` output for one device.
+func parseSmartctl(b []byte) (Disk, error) {
+	var r struct {
+		Device struct {
+			Name string `json:"name"`
+		} `json:"device"`
+		ModelName    string `json:"model_name"`
+		SerialNumber string `json:"serial_number"`
+		UserCapacity struct {
+			Bytes int64 `json:"bytes"`
+		} `json:"user_capacity"`
+		SmartStatus struct {
+			Passed *bool `json:"passed"`
+		} `json:"smart_status"`
+		Temperature struct {
+			Current float64 `json:"current"`
+		} `json:"temperature"`
+	}
+	if err := json.Unmarshal(b, &r); err != nil {
+		return Disk{}, err
+	}
+	d := Disk{Name: r.Device.Name, Model: r.ModelName, Serial: r.SerialNumber, Size: r.UserCapacity.Bytes, TempC: r.Temperature.Current, Source: "smartctl"}
+	if r.SmartStatus.Passed != nil {
+		d.Health = "FAILED"
+		if *r.SmartStatus.Passed {
+			d.Health = "PASSED"
+		}
+	}
+	return d, nil
+}
+
+// runner lets tests replace the smartctl binary.
+type runner func(ctx context.Context, args ...string) ([]byte, error)
+
+func execSmartctl(ctx context.Context, args ...string) ([]byte, error) {
+	// smartctl uses non-zero exit bits to report problems; the JSON is still valid
+	out, err := exec.CommandContext(ctx, "smartctl", args...).Output()
+	if len(out) > 0 {
+		return out, nil
+	}
+	return out, err
+}
+
+// LocalSmart scans for devices and reads each one.
+func LocalSmart(ctx context.Context, run runner) ([]Disk, error) {
+	ctx, cancel := context.WithTimeout(ctx, 20*time.Second)
+	defer cancel()
+	b, err := run(ctx, "--scan", "-j")
+	if err != nil {
+		return nil, err
+	}
+	var scan struct {
+		Devices []struct {
+			Name string `json:"name"`
+		} `json:"devices"`
+	}
+	if err := json.Unmarshal(b, &scan); err != nil {
+		return nil, err
+	}
+	out := []Disk{}
+	for _, dev := range scan.Devices {
+		b, err := run(ctx, "-j", "-H", "-i", "-A", dev.Name)
+		if err != nil {
+			continue
+		}
+		if d, err := parseSmartctl(b); err == nil {
+			if d.Name == "" {
+				d.Name = dev.Name
+			}
+			out = append(out, d)
+		}
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].Name < out[j].Name })
+	return out, nil
+}