vmalert - add expr to variables, add escape functions (#495)

* vmalert - add expr to variables, add escape functions

Co-authored-by: kreedom

app/vmalert/main.go

@@ -121,7 +121,7 @@ func main() {
 	}()
 
 	rh := &requestHandler{m: manager}
-	go httpserver.Serve(*httpListenAddr, (rh).handler)
+	go httpserver.Serve(*httpListenAddr, rh.handler)
 
 	sig := procutil.WaitForSigterm()
 	logger.Infof("service received signal %s", sig)

app/vmalert/notifier/alert.go

@@ -18,6 +18,7 @@ type Alert struct {
 	Annotations map[string]string
 	State       AlertState
 
+	Expr  string
 	Start time.Time
 	End   time.Time
 	Value float64
@@ -52,14 +53,15 @@ func (as AlertState) String() string {
 type alertTplData struct {
 	Labels map[string]string
 	Value  float64
+	Expr   string
 }
 
-const tplHeader = `{{ $value := .Value }}{{ $labels := .Labels }}`
+const tplHeader = `{{ $value := .Value }}{{ $labels := .Labels }}{{ $expr := .Expr }}`
 
 // ExecTemplate executes the Alert template for give
 // map of annotations.
 func (a *Alert) ExecTemplate(annotations map[string]string) (map[string]string, error) {
-	tplData := alertTplData{Value: a.Value, Labels: a.Labels}
+	tplData := alertTplData{Value: a.Value, Labels: a.Labels, Expr: a.Expr}
 	return templateAnnotations(annotations, tplHeader, tplData)
 }
 

app/vmalert/notifier/alert_test.go

@@ -1,22 +1,27 @@
 package notifier
 
 import (
-	"fmt"
+	"net/url"
 	"testing"
 )
 
 func TestAlert_ExecTemplate(t *testing.T) {
+	u, _ := url.Parse("https://victoriametrics.com/path")
+	InitTemplateFunc(u)
 	testCases := []struct {
+		name string
 		alert       *Alert
 		annotations map[string]string
 		expTpl      map[string]string
 	}{
 		{
+			name: "empty-alert",
 			alert:       &Alert{},
 			annotations: map[string]string{},
 			expTpl:      map[string]string{},
 		},
 		{
+			name: "no-template",
 			alert: &Alert{
 				Value: 1e4,
 				Labels: map[string]string{
@@ -27,6 +32,7 @@ func TestAlert_ExecTemplate(t *testing.T) {
 			expTpl:      map[string]string{},
 		},
 		{
+			name: "label-template",
 			alert: &Alert{
 				Value: 1e4,
 				Labels: map[string]string{
@@ -43,10 +49,24 @@ func TestAlert_ExecTemplate(t *testing.T) {
 				"description": "It is 10000 connections for localhost",
 			},
 		},
+		{
+			name: "expression-template",
+			alert: &Alert{
+				Expr:  "vm_rows>0",
+			},
+			annotations: map[string]string{
+				"exprEscapedQuery": "{{ $expr|queryEscape }}",
+				"exprEscapedPath":  "{{ $expr|pathEscape }}",
+			},
+			expTpl: map[string]string{
+				"exprEscapedQuery": "vm_rows%3E0",
+				"exprEscapedPath":  "vm_rows%3E0",
+			},
+		},
 	}
 
-	for i, tc := range testCases {
-		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
 			tpl, err := tc.alert.ExecTemplate(tc.annotations)
 			if err != nil {
 				t.Fatal(err)

app/vmalert/notifier/template_func.go

@@ -142,6 +142,12 @@ func InitTemplateFunc(externalURL *url.URL) {
 		"externalURL": func() string {
 			return externalURL.String()
 		},
+		"pathEscape": func(u string) string {
+			return url.PathEscape(u)
+		},
+		"queryEscape": func(q string) string {
+			return url.QueryEscape(q)
+		},
 	}
 }
 

app/vmalert/rule.go

@@ -152,6 +152,7 @@ func (r *Rule) newAlert(m datasource.Metric) (*notifier.Alert, error) {
 		Labels:  map[string]string{},
 		Value:   m.Value,
 		Start:   time.Now(),
+		Expr:    r.Expr,
 		// TODO: support End time
 	}
 	for _, l := range m.Labels {

app/vmalert/testdata/dir/rules0-good.rules

@@ -6,6 +6,7 @@ groups:
         expr: vm_rows > 0
         labels:
           label: bar
+          expr: "{{ $expr|queryEscape }}"
         annotations:
           summary: "{{ $value|humanize }}"
           description: "{{$labels}}"