feat(influxdb): proper support for group by tags

pkg/tsdb/influxdb/query_builder.go

@@ -88,14 +88,20 @@ func renderWhereClause(query *Query) string {
 }
 
 func renderGroupBy(query *Query) string {
-	var groupBy []string
-	for _, group := range query.GroupBy {
-		groupBy = append(groupBy, group.Render(""))
-	}
+	groupBy := ""
+	for i, group := range query.GroupBy {
+		if i == 0 {
+			groupBy += " GROUP BY"
+		}
+
+		if i > 0 && group.Type != "fill" {
+			groupBy += ", " //fill is special. fill is a creep
+		} else {
+			groupBy += " "
+		}
 
-	if len(groupBy) > 0 {
-		return " GROUP BY " + strings.Join(groupBy, " ")
+		groupBy += group.Render("")
 	}
 
-	return ""
+	return groupBy
 }

pkg/tsdb/influxdb/query_builder_test.go

@@ -16,7 +16,8 @@ func TestInfluxdbQueryBuilder(t *testing.T) {
 		qp2, _ := NewQueryPart("mean", []string{})
 
 		groupBy1, _ := NewQueryPart("time", []string{"$interval"})
-		groupBy2, _ := NewQueryPart("fill", []string{"null"})
+		groupBy2, _ := NewQueryPart("tag", []string{"datacenter"})
+		groupBy3, _ := NewQueryPart("fill", []string{"null"})
 
 		tag1 := &Tag{Key: "hostname", Value: "server1", Operator: "="}
 		tag2 := &Tag{Key: "hostname", Value: "server2", Operator: "=", Condition: "OR"}
@@ -30,7 +31,7 @@ func TestInfluxdbQueryBuilder(t *testing.T) {
 				Selects:     []*Select{{*qp1, *qp2}},
 				Measurement: "cpu",
 				Policy:      "policy",
-				GroupBy:     []*QueryPart{groupBy1, groupBy2},
+				GroupBy:     []*QueryPart{groupBy1, groupBy3},
 				Interval:    "10s",
 			}
 
@@ -43,14 +44,14 @@ func TestInfluxdbQueryBuilder(t *testing.T) {
 			query := &Query{
 				Selects:     []*Select{{*qp1, *qp2}},
 				Measurement: "cpu",
-				GroupBy:     []*QueryPart{groupBy1},
+				GroupBy:     []*QueryPart{groupBy1, groupBy2, groupBy3},
 				Tags:        []*Tag{tag1, tag2},
 				Interval:    "5s",
 			}
 
 			rawQuery, err := builder.Build(query, queryContext)
 			So(err, ShouldBeNil)
-			So(rawQuery, ShouldEqual, `SELECT mean("value") FROM "cpu" WHERE "hostname" = 'server1' OR "hostname" = 'server2' AND time > now() - 5m GROUP BY time(10s)`)
+			So(rawQuery, ShouldEqual, `SELECT mean("value") FROM "cpu" WHERE "hostname" = 'server1' OR "hostname" = 'server2' AND time > now() - 5m GROUP BY time(10s), "datacenter" fill(null)`)
 		})
 
 		Convey("can render time range", func() {