Add functions for regex replacement, sorting and humanizing.

Change-Id: I471c7a8087cd5432b51afce811b591b11583a0c3

templates/templates.go

@@ -17,6 +17,9 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
+	"math"
+	"regexp"
+	"sort"
 	"text/template"
 
 	clientmodel "github.com/prometheus/client_golang/model"
@@ -34,6 +37,23 @@ type sample struct {
 }
 type queryResult []*sample
 
+type queryResultByLabelSorter struct {
+	results queryResult
+	by      string
+}
+
+func (q queryResultByLabelSorter) Len() int {
+	return len(q.results)
+}
+
+func (q queryResultByLabelSorter) Less(i, j int) bool {
+	return q.results[i].Labels[q.by] < q.results[j].Labels[q.by]
+}
+
+func (q queryResultByLabelSorter) Swap(i, j int) {
+	q.results[i], q.results[j] = q.results[j], q.results[i]
+}
+
 // Expand a template, using the given data, time and storage.
 func Expand(text string, name string, data interface{}, timestamp clientmodel.Timestamp, storage metric.PreloadingPersistence) (result string, resultErr error) {
 
@@ -68,6 +88,55 @@ func Expand(text string, name string, data interface{}, timestamp clientmodel.Ti
 		"strvalue": func(s *sample) string {
 			return s.Labels["__value__"]
 		},
+		"reReplaceAll": func(pattern, repl, text string) string {
+			re := regexp.MustCompile(pattern)
+			return re.ReplaceAllString(text, repl)
+		},
+		"sortByLabel": func(label string, v queryResult) queryResult {
+			sorter := queryResultByLabelSorter{v[:], label}
+			sort.Stable(sorter)
+			return v
+		},
+		"humanize": func(v float64) string {
+			if v == 0 {
+				return fmt.Sprintf("%.4g ", v)
+			}
+			if math.Abs(v) >= 1 {
+				prefix := ""
+				for _, p := range []string{"k", "M", "G", "T", "P", "E", "Z", "Y"} {
+					if math.Abs(v) < 1000 {
+						break
+					}
+					prefix = p
+					v /= 1000
+				}
+				return fmt.Sprintf("%.4g %s", v, prefix)
+			} 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 %s", v, prefix)
+			}
+		},
+		"humanize1024": func(v float64) string {
+			if math.Abs(v) <= 1 {
+				return fmt.Sprintf("%.4g ", v)
+			}
+			prefix := ""
+			for _, p := range []string{"ki", "Mi", "Gi", "Ti", "Pi", "Ei", "Zi", "Yi"} {
+				if math.Abs(v) < 1024 {
+					break
+				}
+				prefix = p
+				v /= 1024
+			}
+			return fmt.Sprintf("%.4g %s", v, prefix)
+		},
 	}
 
 	var buffer bytes.Buffer

templates/templates_test.go

@@ -69,6 +69,26 @@ func TestTemplateExpansion(t *testing.T) {
 			text:       "{{ (query \"missing\").banana }}",
 			shouldFail: true,
 		},
+		{
+			// Regex replacement.
+			text:   "{{ reReplaceAll \"(a)b\" \"x$1\" \"ab\" }}",
+			output: "xa",
+		},
+		{
+			// Sorting.
+			text:   "{{ range query \"metric\" | sortByLabel \"instance\" }}{{.Labels.instance}} {{end}}",
+			output: "a b ",
+		},
+		{
+			// Humanize.
+			text:   "{{ 0.0 | humanize }}:{{ 1.0 | humanize }}:{{ 1234567.0 | humanize }}:{{ .12 | humanize }}",
+			output: "0 :1 :1.235 M:120 m",
+		},
+		{
+			// Humanize1024.
+			text:   "{{ 0.0 | humanize1024 }}:{{ 1.0 | humanize1024 }}:{{ 1048576.0 | humanize1024 }}:{{ .12 | humanize1024}}",
+			output: "0 :1 :1 Mi:0.12 ",
+		},
 	}
 
 	time := clientmodel.Timestamp(0)