Make aliasByTags to work correctly with other functions

Fixes #422

cmd/mockbackend/aliasByTags2.yaml

@@ -0,0 +1,10 @@
+listeners:
+        - address: ":9070"
+          expressions:
+              "seriesByTag('hostname=gateway1', 'ifName=~GigabitEthernet0/0/0', 'name=~interface_(in|out)_octets')":
+                  pathExpression: "seriesByTag('hostname=gateway1', 'ifName=~GigabitEthernet0/0/0', 'name=~interface_(in|out)_octets')"
+                  data:
+                      - metricName: "metric.interface_in_octets;ifName=GigabitEthernet0/0/0;hostname=gateway1"
+                        values: [1.0, .NaN, 2.0, 3.0, 4.0, 5.0]
+                      - metricName: "metric.interface_out_octets;ifName=GigabitEthernet0/0/0;hostname=gateway1"
+                        values: [2.0, .NaN, 3.0, .NaN, 5.0, 6.0]

cmd/mockbackend/main.go

@@ -44,6 +44,24 @@ type Metric struct {
 	Values     []float64 `yaml:"values"`
 }
 
+type metricForJson struct {
+	MetricName string
+	Values []string
+}
+
+func (m *Metric) MarshalJSON() ([]byte, error) {
+	m2 := metricForJson{
+		MetricName: m.MetricName,
+		Values: make([]string, len(m.Values)),
+	}
+
+	for i, v := range m.Values {
+		m2.Values[i] = fmt.Sprintf("%v", v)
+	}
+
+	return json.Marshal(m2)
+}
+
 type Response struct {
 	PathExpression string   `yaml:"pathExpression"`
 	Data           []Metric `yaml:"data"`

expr/functions/aliasByTags/function.go

@@ -1,7 +1,6 @@
 package aliasByTags
 
 import (
-	"fmt"
 	"github.com/go-graphite/carbonapi/expr/helper"
 	"github.com/go-graphite/carbonapi/expr/interfaces"
 	"github.com/go-graphite/carbonapi/expr/types"
@@ -10,8 +9,6 @@ import (
 	"strings"
 )
 
-const NAME = "name"
-
 type aliasByTags struct {
 	interfaces.FunctionBase
 }
@@ -29,37 +26,22 @@ func New(configFile string) []interfaces.FunctionMetadata {
 	return res
 }
 
-func metricToTagMap(s string) map[string]string {
-	r := make(map[string]string)
-	for _, p := range strings.Split(s, ";") {
-		if strings.Contains(p, "=") {
-			tagValue := strings.SplitN(p, "=", 2)
-			r[tagValue[0]] = tagValue[1]
-		} else {
-			r[NAME] = p
-		}
-	}
-	return r
-}
-
 func (f *aliasByTags) Do(e parser.Expr, from, until int64, values map[parser.MetricRequest][]*types.MetricData) ([]*types.MetricData, error) {
 	args, err := helper.GetSeriesArg(e.Args()[0], from, until, values)
 	if err != nil {
-		fmt.Println("getSeriesArg missing argument")
 		return nil, err
 	}
 
 	tags, err := e.GetNodeOrTagArgs(1)
 	if err != nil {
-		fmt.Println("GetNodeOrTagArgs missing argument")
 		return nil, err
 	}
 
 	var results []*types.MetricData
 
 	for _, a := range args {
 		var matched []string
-		metricTags := metricToTagMap(a.Name)
+		metricTags := a.Tags
 		nodes := strings.Split(metricTags["name"], ".")
 		for _, tag := range tags {
 			if tag.IsTag {

expr/functions/aliasByTags/function_test.go

@@ -1,6 +1,7 @@
 package aliasByTags
 
 import (
+	"math"
 	"testing"
 	"time"
 
@@ -9,16 +10,23 @@ import (
 	"github.com/go-graphite/carbonapi/expr/types"
 	"github.com/go-graphite/carbonapi/pkg/parser"
 	th "github.com/go-graphite/carbonapi/tests"
+
+	"github.com/go-graphite/carbonapi/expr/functions/perSecond"
 )
 
 func init() {
 	md := New("")
-	evaluator := th.EvaluatorFromFunc(md[0].F)
-	metadata.SetEvaluator(evaluator)
-	helper.SetEvaluator(evaluator)
 	for _, m := range md {
 		metadata.RegisterFunction(m.Name, m.F)
 	}
+	psFunc := perSecond.New("")
+	for _, m := range psFunc {
+		metadata.RegisterFunction(m.Name, m.F)
+	}
+
+	evaluator := th.EvaluatorFromFuncWithMetadata(metadata.FunctionMD.Functions)
+	metadata.SetEvaluator(evaluator)
+	helper.SetEvaluator(evaluator)
 }
 
 func TestAliasByTags(t *testing.T) {
@@ -53,6 +61,13 @@ func TestAliasByTags(t *testing.T) {
 			},
 			[]*types.MetricData{types.MakeMetricData("bam.bar.metric1", []float64{1, 2, 3, 4, 5}, 1, now32)},
 		},
+		{
+			`aliasByTags(perSecond(*), 'name')`,
+			map[parser.MetricRequest][]*types.MetricData{
+				{"*", 0, 1}: {types.MakeMetricData("base.metric1;foo=bar;baz=bam", []float64{1, 2, 3, 4, 5}, 1, now32)},
+			},
+			[]*types.MetricData{types.MakeMetricData("base.metric1", []float64{math.NaN(), 1, 1, 1, 1}, 1, now32)},
+		},
 	}
 
 	for _, tt := range tests {