Add humanizeDuration function.

This attempts to reasonably handle things from weekly cronjobs,
to rpcs taking ns to things that are usually ms but jump to over a second.

For consistency, stop putting spaces before prefixes.

Change-Id: I6407879187b25680b323cd70254e205315b5fc3c

templates/templates.go

@@ -138,7 +138,7 @@ func NewTemplateExpander(text string, name string, data interface{}, timestamp c
 			},
 			"humanize": func(v float64) string {
 				if v == 0 {
-					return fmt.Sprintf("%.4g ", v)
+					return fmt.Sprintf("%.4g", v)
 				}
 				if math.Abs(v) >= 1 {
 					prefix := ""
@@ -149,7 +149,7 @@ func NewTemplateExpander(text string, name string, data interface{}, timestamp c
 						prefix = p
 						v /= 1000
 					}
-					return fmt.Sprintf("%.4g %s", v, prefix)
+					return fmt.Sprintf("%.4g%s", v, prefix)
 				} else {
 					prefix := ""
 					for _, p := range []string{"m", "u", "n", "p", "f", "a", "z", "y"} {
@@ -159,12 +159,12 @@ func NewTemplateExpander(text string, name string, data interface{}, timestamp c
 						prefix = p
 						v *= 1000
 					}
-					return fmt.Sprintf("%.4g %s", v, prefix)
+					return fmt.Sprintf("%.4g%s", v, prefix)
 				}
 			},
 			"humanize1024": func(v float64) string {
 				if math.Abs(v) <= 1 {
-					return fmt.Sprintf("%.4g ", v)
+					return fmt.Sprintf("%.4g", v)
 				}
 				prefix := ""
 				for _, p := range []string{"ki", "Mi", "Gi", "Ti", "Pi", "Ei", "Zi", "Yi"} {
@@ -174,7 +174,45 @@ func NewTemplateExpander(text string, name string, data interface{}, timestamp c
 					prefix = p
 					v /= 1024
 				}
-				return fmt.Sprintf("%.4g %s", v, prefix)
+				return fmt.Sprintf("%.4g%s", v, prefix)
+			},
+			"humanizeDuration": func(v float64) string {
+				if v == 0 {
+					return fmt.Sprintf("%.4gs", v)
+				}
+				if math.Abs(v) >= 1 {
+					sign := ""
+					if v < 0 {
+						sign = "-"
+						v = -v
+					}
+					seconds := math.Mod(v, 60)
+					minutes := (int64(v) / 60) % 60
+					hours := (int64(v) / 60 / 60) % 24
+					days := (int64(v) / 60 / 60 / 24)
+					// For days to minutes, we display seconds as an integer.
+					if days != 0 {
+						return fmt.Sprintf("%s%dd %dh %dm %.0fs", sign, days, hours, minutes, seconds)
+					}
+					if hours != 0 {
+						return fmt.Sprintf("%s%dh %dm %.0fs", sign, hours, minutes, seconds)
+					}
+					if minutes != 0 {
+						return fmt.Sprintf("%s%dm %.0fs", sign, minutes, seconds)
+					}
+					// For seconds, we display 4 significant digts.
+					return fmt.Sprintf("%s%.4gs", sign, math.Floor(seconds*1000+.5)/1000)
+				} else {
+					prefix := ""
+					for _, p := range []string{"m", "u", "n", "p", "f", "a", "z", "y"} {
+						if math.Abs(v) >= 1 {
+							break
+						}
+						prefix = p
+						v *= 1000
+					}
+					return fmt.Sprintf("%.4g%ss", v, prefix)
+				}
 			},
 		},
 	}

templates/templates_test.go

@@ -24,6 +24,7 @@ import (
 type testTemplatesScenario struct {
 	text       string
 	output     string
+	input      interface{}
 	shouldFail bool
 	html       bool
 }
@@ -104,13 +105,27 @@ func TestTemplateExpansion(t *testing.T) {
 		},
 		{
 			// Humanize.
-			text:   "{{ 0.0 | humanize }}:{{ 1.0 | humanize }}:{{ 1234567.0 | humanize }}:{{ .12 | humanize }}",
-			output: "0 :1 :1.235 M:120 m",
+			text:   "{{ range . }}{{ humanize . }}:{{ end }}",
+			input:  []float64{0.0, 1.0, 1234567.0, .12},
+			output: "0:1:1.235M:120m:",
 		},
 		{
 			// Humanize1024.
-			text:   "{{ 0.0 | humanize1024 }}:{{ 1.0 | humanize1024 }}:{{ 1048576.0 | humanize1024 }}:{{ .12 | humanize1024}}",
-			output: "0 :1 :1 Mi:0.12 ",
+			text:   "{{ range . }}{{ humanize1024 . }}:{{ end }}",
+			input:  []float64{0.0, 1.0, 1048576.0, .12},
+			output: "0:1:1Mi:0.12:",
+		},
+		{
+			// HumanizeDuration - seconds.
+			text:   "{{ range . }}{{ humanizeDuration . }}:{{ end }}",
+			input:  []float64{0, 1, 60, 3600, 86400, 86400 + 3600, -(86400*2 + 3600*3 + 60*4 + 5)},
+			output: "0s:1s:1m 0s:1h 0m 0s:1d 0h 0m 0s:1d 1h 0m 0s:-2d 3h 4m 5s:",
+		},
+		{
+			// HumanizeDuration - subsecond and fractional seconds.
+			text:   "{{ range . }}{{ humanizeDuration . }}:{{ end }}",
+			input:  []float64{.1, .0001, .12345, 60.1, 60.5, 1.2345, 12.345},
+			output: "100ms:100us:123.5ms:1m 0s:1m 0s:1.235s:12.35s:",
 		},
 		{
 			// Title.
@@ -145,7 +160,7 @@ func TestTemplateExpansion(t *testing.T) {
 	for _, s := range scenarios {
 		var result string
 		var err error
-		expander := NewTemplateExpander(s.text, "test", nil, time, ts)
+		expander := NewTemplateExpander(s.text, "test", s.input, time, ts)
 		if s.html {
 			result, err = expander.ExpandHTML(nil)
 		} else {