[Agent] Replace dockerapi container with Redis-based control bus

data/Dockerfiles/agent/internal/services/host.go

@@ -0,0 +1,236 @@
+package services
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/mailcow/mailcow-dockerized/agent/internal/commands"
+	"github.com/mailcow/mailcow-dockerized/agent/internal/proc"
+)
+
+func init() { Register("host", buildHost) }
+
+// hostProcRoot is where the host-agent container mounts /proc. If we're not
+// running as host-agent, falling back to /proc still produces sensible numbers
+// (the container's own view) so dashboards don't blank out in unit tests.
+var hostProcRoot = "/host/proc"
+
+func resolveProc(p string) string {
+	if _, err := os.Stat(hostProcRoot); err == nil {
+		return hostProcRoot + p
+	}
+	return "/proc" + p
+}
+
+func buildHost(_ *proc.Supervisor) *commands.Table {
+	t := commands.New("host")
+	// No lifecycle — the host-agent container has no main process to manage.
+
+	t.Register("exec.df", func(ctx context.Context, args map[string]any) (any, error) {
+		path := commands.ArgStringOpt(args, "path", "/")
+		var stat syscall.Statfs_t
+		if err := syscall.Statfs(path, &stat); err != nil {
+			return nil, fmt.Errorf("statfs %s: %w", path, err)
+		}
+		size := int64(stat.Blocks) * int64(stat.Bsize)
+		free := int64(stat.Bavail) * int64(stat.Bsize)
+		used := size - free
+		return map[string]any{
+			"path":      path,
+			"size":      size,
+			"used":      used,
+			"available": free,
+		}, nil
+	})
+
+	t.Register("exec.host-stats", func(ctx context.Context, _ map[string]any) (any, error) {
+		return readHostStats()
+	})
+
+	return t
+}
+
+func readHostStats() (map[string]any, error) {
+	out := map[string]any{
+		"system_time":  time.Now().Format("2006-01-02 15:04:05"),
+		"architecture": readArchitecture(),
+	}
+
+	if uptime, err := readUptime(); err == nil {
+		out["uptime"] = int64(uptime)
+	} else {
+		out["uptime"] = int64(0)
+	}
+
+	cores := readCPUCores()
+	cpuUsage, _ := sampleHostCPU(500 * time.Millisecond)
+	out["cpu"] = map[string]any{
+		"cores": cores,
+		"usage": cpuUsage,
+	}
+
+	memTotal, memUsage := readMemoryTotalAndUsagePct()
+	out["memory"] = map[string]any{
+		"total": memTotal, // bytes
+		"usage": memUsage, // percent 0..100
+	}
+
+	return out, nil
+}
+
+// readArchitecture returns the host's machine architecture (e.g. "x86_64",
+// "aarch64"). Falls back to a single dash if syscall.Uname fails.
+func readArchitecture() string {
+	var u syscall.Utsname
+	if err := syscall.Uname(&u); err != nil {
+		return "-"
+	}
+	return charsToString(u.Machine[:])
+}
+
+func charsToString(b []int8) string {
+	out := make([]byte, 0, len(b))
+	for _, c := range b {
+		if c == 0 {
+			break
+		}
+		out = append(out, byte(c))
+	}
+	return string(out)
+}
+
+// readCPUCores counts `^processor` lines in /proc/cpuinfo. On a container
+// with /host/proc bind-mounted this gives the host's logical CPU count,
+// not the container's cgroup limits.
+func readCPUCores() int {
+	f, err := os.Open(resolveProc("/cpuinfo"))
+	if err != nil {
+		return 0
+	}
+	defer f.Close()
+	n := 0
+	sc := bufio.NewScanner(f)
+	for sc.Scan() {
+		if strings.HasPrefix(sc.Text(), "processor") {
+			n++
+		}
+	}
+	return n
+}
+
+// readMemoryTotalAndUsagePct reads /proc/meminfo and returns (total_bytes,
+// usage_pct_0_100). "Usage" is computed as (Total - Available)/Total which
+// matches what tools like `free` show as "used".
+func readMemoryTotalAndUsagePct() (int64, int) {
+	f, err := os.Open(resolveProc("/meminfo"))
+	if err != nil {
+		return 0, 0
+	}
+	defer f.Close()
+
+	var total, available int64
+	sc := bufio.NewScanner(f)
+	for sc.Scan() {
+		fields := strings.Fields(sc.Text())
+		if len(fields) < 2 {
+			continue
+		}
+		switch fields[0] {
+		case "MemTotal:":
+			total = parseInt64(fields[1]) * 1024
+		case "MemAvailable:":
+			available = parseInt64(fields[1]) * 1024
+		}
+	}
+	if total <= 0 {
+		return 0, 0
+	}
+	used := total - available
+	if available <= 0 {
+		used = total
+	}
+	pct := int(float64(used) / float64(total) * 100.0)
+	if pct < 0 {
+		pct = 0
+	}
+	if pct > 100 {
+		pct = 100
+	}
+	return total, pct
+}
+
+func readUptime() (float64, error) {
+	b, err := os.ReadFile(resolveProc("/uptime"))
+	if err != nil {
+		return 0, err
+	}
+	fields := strings.Fields(string(b))
+	if len(fields) < 1 {
+		return 0, fmt.Errorf("malformed uptime")
+	}
+	return strconv.ParseFloat(fields[0], 64)
+}
+
+// sampleHostCPU returns CPU utilization (0..100) sampled over `window`.
+func sampleHostCPU(window time.Duration) (float64, error) {
+	a, err := readCPULine()
+	if err != nil {
+		return 0, err
+	}
+	time.Sleep(window)
+	b, err := readCPULine()
+	if err != nil {
+		return 0, err
+	}
+	totalA, totalB := sum(a), sum(b)
+	idleA, idleB := a[3], b[3]
+	dTotal, dIdle := totalB-totalA, idleB-idleA
+	if dTotal == 0 {
+		return 0, nil
+	}
+	return 100.0 * float64(dTotal-dIdle) / float64(dTotal), nil
+}
+
+func readCPULine() ([]int64, error) {
+	f, err := os.Open(resolveProc("/stat"))
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	sc := bufio.NewScanner(f)
+	if !sc.Scan() {
+		return nil, fmt.Errorf("empty /proc/stat")
+	}
+	fields := strings.Fields(sc.Text())
+	if len(fields) < 5 || fields[0] != "cpu" {
+		return nil, fmt.Errorf("unexpected /proc/stat first line")
+	}
+	out := make([]int64, 0, len(fields)-1)
+	for _, f := range fields[1:] {
+		n, err := strconv.ParseInt(f, 10, 64)
+		if err != nil {
+			return nil, err
+		}
+		out = append(out, n)
+	}
+	return out, nil
+}
+
+func sum(xs []int64) int64 {
+	var s int64
+	for _, x := range xs {
+		s += x
+	}
+	return s
+}
+
+func parseInt64(s string) int64 {
+	n, _ := strconv.ParseInt(s, 10, 64)
+	return n
+}