Add increase() function, to replace delta(..., 1).

This calculates how much a counter increases over
a given period of time, which is the area under the curve
of it's rate.

increase(x[5m]) is equivilent to rate(x[5m]) * 300.

promql/functions.go

@@ -118,6 +118,13 @@ func funcRate(ev *evaluator, args Expressions) Value {
 	return vector
 }
 
+// === increase(node ExprMatrix) Vector ===
+func funcIncrease(ev *evaluator, args Expressions) Value {
+	args = append(args, &NumberLiteral{1})
+	vector := funcDelta(ev, args).(Vector)
+	return vector
+}
+
 // === sort(node ExprVector) Vector ===
 func funcSort(ev *evaluator, args Expressions) Value {
 	byValueSorter := vectorByValueHeap(ev.evalVector(args[0]))
@@ -572,6 +579,12 @@ var functions = map[string]*Function{
 		ReturnType: ExprVector,
 		Call:       funcAbsent,
 	},
+	"increase": {
+		Name:       "increase",
+		ArgTypes:   []ExprType{ExprMatrix},
+		ReturnType: ExprVector,
+		Call:       funcIncrease,
+	},
 	"avg_over_time": {
 		Name:       "avg_over_time",
 		ArgTypes:   []ExprType{ExprMatrix},

promql/quantile.go

@@ -25,8 +25,8 @@ import (
 // excludedLabels are the labels to exclude from signature calculation for
 // quantiles.
 var excludedLabels = map[clientmodel.LabelName]struct{}{
-	clientmodel.MetricNameLabel: struct{}{},
-	clientmodel.BucketLabel:     struct{}{},
+	clientmodel.MetricNameLabel: {},
+	clientmodel.BucketLabel:     {},
 }
 
 type bucket struct {

promql/testdata/functions.test

@@ -49,3 +49,16 @@ eval instant at 50m changes(http_requests[50m])
 	{path="/biz"} 1
 
 eval instant at 50m changes(nonexistent_metric[50m])
+
+
+clear
+
+# Tests for increase().
+load 5m
+	http_requests{path="/foo"}	0+10x10
+	http_requests{path="/bar"}	0+10x5 0+10x5
+
+# Tests for increase().
+eval instant at 50m increase(http_requests[50m])
+	{path="/foo"} 100
+	{path="/bar"}  90

retrieval/targetmanager.go

@@ -310,7 +310,7 @@ func (tm *TargetManager) targetsFromGroup(tg *config.TargetGroup, cfg *config.Sc
 		// set already. Apply the labelsets in order of decreasing precedence.
 		labelsets := []clientmodel.LabelSet{
 			tg.Labels,
-			clientmodel.LabelSet{
+			{
 				clientmodel.MetricsPathLabel: clientmodel.LabelValue(cfg.MetricsPath),
 				clientmodel.JobLabel:         clientmodel.LabelValue(cfg.JobName),
 			},

retrieval/targetmanager_test.go

@@ -43,7 +43,7 @@ func TestTargetManagerChan(t *testing.T) {
 	targetManager := &TargetManager{
 		sampleAppender: nopAppender{},
 		providers: map[*config.ScrapeConfig][]TargetProvider{
-			testJob1: []TargetProvider{prov1},
+			testJob1: {prov1},
 		},
 		targets: make(map[string][]*Target),
 	}