dashboard: CPU, memory, diskIO and traffic on the footer (#15950)

* dashboard: footer, deep state update

* dashboard: resolve asset path

* dashboard: prevent state update on every reconnection

* dashboard: fix linter issue

* dashboard, cmd: minor UI fix, include commit hash

* dashboard: gitCommit renamed to commit

* dashboard: move the geth version to the right, make commit optional

* dashboard: memory, traffic and CPU on footer

* dashboard: fix merge

* dashboard: CPU, diskIO on footer

* dashboard: rename variables, use group declaration

* dashboard: docs

vendor/github.com/elastic/gosigar/sigar_format.go

@@ -0,0 +1,126 @@
+// Copyright (c) 2012 VMware, Inc.
+
+package gosigar
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"strconv"
+	"time"
+)
+
+// Go version of apr_strfsize
+func FormatSize(size uint64) string {
+	ord := []string{"K", "M", "G", "T", "P", "E"}
+	o := 0
+	buf := new(bytes.Buffer)
+	w := bufio.NewWriter(buf)
+
+	if size < 973 {
+		fmt.Fprintf(w, "%3d ", size)
+		w.Flush()
+		return buf.String()
+	}
+
+	for {
+		remain := size & 1023
+		size >>= 10
+
+		if size >= 973 {
+			o++
+			continue
+		}
+
+		if size < 9 || (size == 9 && remain < 973) {
+			remain = ((remain * 5) + 256) / 512
+			if remain >= 10 {
+				size++
+				remain = 0
+			}
+
+			fmt.Fprintf(w, "%d.%d%s", size, remain, ord[o])
+			break
+		}
+
+		if remain >= 512 {
+			size++
+		}
+
+		fmt.Fprintf(w, "%3d%s", size, ord[o])
+		break
+	}
+
+	w.Flush()
+	return buf.String()
+}
+
+func FormatPercent(percent float64) string {
+	return strconv.FormatFloat(percent, 'f', -1, 64) + "%"
+}
+
+func (self *FileSystemUsage) UsePercent() float64 {
+	b_used := (self.Total - self.Free) / 1024
+	b_avail := self.Avail / 1024
+	utotal := b_used + b_avail
+	used := b_used
+
+	if utotal != 0 {
+		u100 := used * 100
+		pct := u100 / utotal
+		if u100%utotal != 0 {
+			pct += 1
+		}
+		return (float64(pct) / float64(100)) * 100.0
+	}
+
+	return 0.0
+}
+
+func (self *Uptime) Format() string {
+	buf := new(bytes.Buffer)
+	w := bufio.NewWriter(buf)
+	uptime := uint64(self.Length)
+
+	days := uptime / (60 * 60 * 24)
+
+	if days != 0 {
+		s := ""
+		if days > 1 {
+			s = "s"
+		}
+		fmt.Fprintf(w, "%d day%s, ", days, s)
+	}
+
+	minutes := uptime / 60
+	hours := minutes / 60
+	hours %= 24
+	minutes %= 60
+
+	fmt.Fprintf(w, "%2d:%02d", hours, minutes)
+
+	w.Flush()
+	return buf.String()
+}
+
+func (self *ProcTime) FormatStartTime() string {
+	if self.StartTime == 0 {
+		return "00:00"
+	}
+	start := time.Unix(int64(self.StartTime)/1000, 0)
+	format := "Jan02"
+	if time.Since(start).Seconds() < (60 * 60 * 24) {
+		format = "15:04"
+	}
+	return start.Format(format)
+}
+
+func (self *ProcTime) FormatTotal() string {
+	t := self.Total / 1000
+	ss := t % 60
+	t /= 60
+	mm := t % 60
+	t /= 60
+	hh := t % 24
+	return fmt.Sprintf("%02d:%02d:%02d", hh, mm, ss)
+}