Render output as colored tables with pass/fail verdict

render.go

@@ -0,0 +1,231 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+)
+
+const (
+	cReset  = "\x1b[0m"
+	cBold   = "\x1b[1m"
+	cDim    = "\x1b[2m"
+	cRed    = "\x1b[31m"
+	cGreen  = "\x1b[32m"
+	cYellow = "\x1b[33m"
+	cCyan   = "\x1b[36m"
+	cGrey   = "\x1b[90m"
+)
+
+var useColor bool
+
+func initColor(mode string) error {
+	switch mode {
+	case "always":
+		useColor = true
+	case "never":
+		useColor = false
+	case "auto":
+		if os.Getenv("NO_COLOR") != "" || os.Getenv("TERM") == "dumb" {
+			useColor = false
+			return nil
+		}
+		st, err := os.Stdout.Stat()
+		useColor = err == nil && st.Mode()&os.ModeCharDevice != 0
+	default:
+		return fmt.Errorf("unknown color mode %q (want auto, always, never)", mode)
+	}
+	return nil
+}
+
+func paint(s, code string) string {
+	if !useColor || s == "" {
+		return s
+	}
+	return code + s + cReset
+}
+
+func stripANSI(s string) string {
+	var b strings.Builder
+	for i := 0; i < len(s); {
+		if s[i] == 0x1b {
+			for i < len(s) && s[i] != 'm' {
+				i++
+			}
+			if i < len(s) {
+				i++
+			}
+			continue
+		}
+		b.WriteByte(s[i])
+		i++
+	}
+	return b.String()
+}
+
+func visWidth(s string) int {
+	return len([]rune(stripANSI(s)))
+}
+
+func pad(s string, w int, right bool) string {
+	gap := w - visWidth(s)
+	if gap < 0 {
+		gap = 0
+	}
+	if right {
+		return strings.Repeat(" ", gap) + s
+	}
+	return s + strings.Repeat(" ", gap)
+}
+
+func commas(v uint64) string {
+	s := fmt.Sprintf("%d", v)
+	if len(s) <= 3 {
+		return s
+	}
+	var parts []string
+	for len(s) > 3 {
+		parts = append([]string{s[len(s)-3:]}, parts...)
+		s = s[:len(s)-3]
+	}
+	return strings.Join(append([]string{s}, parts...), ",")
+}
+
+func humanBytes(b uint64) string {
+	const unit = 1000.0
+	v := float64(b)
+	for _, suffix := range []string{"B", "kB", "MB", "GB", "TB"} {
+		if v < unit {
+			return fmt.Sprintf("%.1f %s", v, suffix)
+		}
+		v /= unit
+	}
+	return fmt.Sprintf("%.1f PB", v)
+}
+
+type colSpec struct {
+	title string
+	width int
+	right bool
+}
+
+type streamTable struct {
+	cols        []colSpec
+	sinceHeader int
+	headerEvery int
+}
+
+func (t *streamTable) headerLines() []string {
+	var titles, rules []string
+	for _, c := range t.cols {
+		titles = append(titles, pad(c.title, c.width, c.right))
+		rules = append(rules, strings.Repeat("─", c.width))
+	}
+	return []string{
+		paint(strings.Join(titles, " "), cBold),
+		paint(strings.Join(rules, " "), cGrey),
+	}
+}
+
+func (t *streamTable) emit(cells []string) []string {
+	var out []string
+	if t.sinceHeader == 0 || (t.headerEvery > 0 && t.sinceHeader >= t.headerEvery) {
+		out = append(out, t.headerLines()...)
+		t.sinceHeader = 0
+	}
+	var padded []string
+	for i, c := range t.cols {
+		v := ""
+		if i < len(cells) {
+			v = cells[i]
+		}
+		padded = append(padded, pad(v, c.width, c.right))
+	}
+	t.sinceHeader++
+	return append(out, strings.Join(padded, " "))
+}
+
+func renderBox(title string, headers []string, rights []bool, rows [][]string) string {
+	n := len(headers)
+	widths := make([]int, n)
+	for i, h := range headers {
+		widths[i] = visWidth(h)
+	}
+	for _, r := range rows {
+		for i := 0; i < n && i < len(r); i++ {
+			if w := visWidth(r[i]); w > widths[i] {
+				widths[i] = w
+			}
+		}
+	}
+
+	line := func(l, m, r string) string {
+		var parts []string
+		for _, w := range widths {
+			parts = append(parts, strings.Repeat("─", w+2))
+		}
+		return paint(l+strings.Join(parts, m)+r, cGrey)
+	}
+	rowText := func(cells []string, bold bool) string {
+		var parts []string
+		for i := 0; i < n; i++ {
+			v := ""
+			if i < len(cells) {
+				v = cells[i]
+			}
+			if bold {
+				v = paint(v, cBold)
+			}
+			parts = append(parts, " "+pad(v, widths[i], rights[i])+" ")
+		}
+		bar := paint("│", cGrey)
+		return bar + strings.Join(parts, bar) + bar
+	}
+
+	var b strings.Builder
+	if title != "" {
+		b.WriteString(paint(title, cBold+cCyan) + "\n")
+	}
+	b.WriteString(line("┌", "┬", "┐") + "\n")
+	b.WriteString(rowText(headers, true) + "\n")
+	b.WriteString(line("├", "┼", "┤") + "\n")
+	for _, r := range rows {
+		b.WriteString(rowText(r, false) + "\n")
+	}
+	b.WriteString(line("└", "┴", "┘"))
+	return b.String()
+}
+
+func statusCell(v uint64) string {
+	s := commas(v)
+	if v == 0 {
+		return paint(s, cGreen)
+	}
+	return paint(s, cRed)
+}
+
+func gapCell(v int64) string {
+	if v <= 0 {
+		return paint("0", cGreen)
+	}
+	return paint(commas(uint64(v)), cYellow)
+}
+
+func lostCell(v int64) string {
+	if v <= 0 {
+		return paint("0", cGreen)
+	}
+	return paint(commas(uint64(v)), cRed)
+}
+
+func rateCell(gb float64, target float64) string {
+	s := fmt.Sprintf("%.2f", gb)
+	switch {
+	case gb >= target*0.995:
+		return paint(s, cGreen)
+	case gb >= target*0.90:
+		return paint(s, cYellow)
+	default:
+		return paint(s, cRed)
+	}
+}